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T M 1 1 - 5 8 9 5 - 1 0 1 2 - 1 0 WARNING WARNING DANGEROUS VOLTAGES are present during the preparation of the test circuits 6-20. Turn all power switches off before constructing them test circuits. Failure could result in serious injury or death. TM 11-5895-1012-10 TECHNICAL MANUAL DEPARTMENT OF THE ARMY WASHINGTON, DC, 4 January 1978 No. 11-5895-1012-10 OPERATOR'S MANUAL TECHNICAL CONTROL FACILITY (GENERAL) REPORTING OF ERRORS You can improve this manual by recommending improvements using DA Form 2028-2 (Test) located in the back of the manual. Simply tear out the self-addressed form, fill it out as shown on the sample, fold it where shown,, and drop it in the mail. If there are no blank DA Forms 20-28-2 (Test) forms in the back of the manual, use the standard DA For 20-28 (Recommended Changes to Publications and Blank Forms) and forward to Commander, US Army Electronics Command, ATTN: DRSEL-MA-Q, Fort Monmouth, New Jersey 07703. In either case a reply will be furnished direct to you. TABLE OF CONTENTS CHAPTER CHAPTER Section CHAPTER Section CHAPTER Section Section CHAPTER CHAPTER APPENDIX APPENDIX INDEX Number 2-1, 2-2, 2-3, 2-4, 2-6, 2-6, 2-7, 2-81, 2-82, 2-83, 2-84, 2-85, 2-9, 2-10, 2-11, 1. 2. I. II. III. IV. 3. I. II. III. 4. I. II. III. IV. V. VI. VII. VIII. 5. 6. A. B. .... .. INTRODUCTION DESCRIPTION OF TECHNICAL CONTROL FACILITY General... . . . . . . . . . . . . . . . . . . . . . . System Service Interfaces, and Types of Signals . . . . . The Technical Control Facility . . . . . . . . . . . . . Representative TCF Equipment . . . . . . . . . EXAMPLES OF OPERATIONAL TCF'S Pirmasens . . . . . . . . . . . . . . . . . . . . . Berlin............ ......... . . . ....... . Pentagon . . . . . . . . . . . . TCF OPERATIONS . . Operation Practices and Methods. . . . . ... circuit Rerouting . . . . . . Patching Operations. . . . . . . . . . . . . . . . Failures and Fault Isolation . . . . . . . . . . Performance Standards and Test Measurements . Circuit Performance and Quality Control Testing . Implementation of Communications Services Requirements Acceptability of New Equipment . . . . STATION MAINTENANCE . TEST PROCEDURES... . . . . . . . . . . . REFERENCES.. . : . ABBREVIATIONS.. . . .. ... . . . . .. . . Paragraph Page 1-1. , 1-1 2-1. 2-7. 2-15. 2-30. , , , , 2-1 2-4 2-11 2-34 3-1. , 3-1 3-4. , 3-3 3-7. , 3-6 . . . 4-1. 4-13. 4-17. 4-22. 4-39. 4-46. 4-56. 4-60. 5-1. 6-1. LIST OF ILLUSTRATIONS Title . .. Example of a world-wide common user network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... . . . .. Interconnection of communications facilities, simplified diagram . . . . . . . . . . Subsystem interface with the DCS. . . . . . . . . . . . . . . . . . AUTODIN Interface with the DCS .......... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Technical Control Facility, interface diagram . ................... Technical Control Facility, configuration block diagram . . : . . . .. . . . . . . . . Technical Control Facility, typical floor plan . . . . . . . . .. ..... : .. ... : Typical voice frequency circuits (Sheet 1 of 5)....... . . . . ... .. . Typical voice frequency circuits (Sheet 2 of 5) ..... .. . . . ... . .. . ... Typical voice frequency circuits (sheet 3 of 5) . ...... . . ..... .. -Typical voice frequency circuits (sheet 4 of 5) . . . . . . . . . : . Typical voice frequency circuits (sheet 5 of 5) . . . . . . . . . . . . . . . . ... .. .......... ......... Standard dc/data access circuits.. . . . . . . . . . . . . . . . . .. Double bus arrangement and automatic transfer panel, wiring diagram.:. . . . . .... . . . Uninterruptible power supply in standby condition. . . . . . . . . . . . . . . ......... . . . . . . . . . . . . . . . . . . . , . . . . , , , , , , , , , , 4-1 4-4 4-6 4-12 4-31 4-39 4-46 4-49 5-1 6-1 A-1 B-1 Index 1 Page 2-5 2-7 2-9 2-10 2-13 2-14 2-16 2-17 2-18 2-20 2-21 2-23 2-25 2-29 2-31 i TM 11-5895-1012-10 Number 2-12 2-13 2-14 2-16 2-16 2-17 2-18 2-19 2-20 2-21 2-22 2-23 2-24 2-25 2-26 2-27 3-1 3-2 3-3 3-4 4-1 4-2 4-3 4-4 4-6 4-6 4-71 4-72 4-81 4-82 4-83 4-91 4-92 4-10 4-11 4-12 4-13 4-141 4-142 4-143 6-1 6-2 6-3 6-4 6-5 6-6 6-7 6-8 6-9 6-10 6-11 6-12 6-13 6-14 6-15 6-16 6-17 6-18 6-19 6-20 FO-1 FO-2 FO-3 FO-4 FO-5 FO-6 ii Title Page 2-31 . . . . . . . ............................................... Uninterruptible power supply in on-line condition 2-32 ADMSC uninterruptible power system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-34 Solid state uninterruptible power system, simplified block d&gram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-39 Voice frequency primary or equal level and signaling patch panels front view . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-40 E&M patch panel, interconnection diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-41 Two-wire voice frequency primary patch panel, interconnection diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-43 Dc patch panel, low level receive, interconnection diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-44 Dc patch panel, low level transmit, interconnection diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-46 DC patch panel (transmit or receive) with cut keys and lamps, front view . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-47 Typical miscellaneous patch panel, front view . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-48 Miscellaneous/interbay patch panel, interconnection diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-49 Voice frequency interbay patch panel, interconnection diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-50 Typical series and parallel interbay trunking systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-51 DC interbay patch panel with 48 lamps, front view . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-52 DC interbay patch panel with 48 lamps, interconnection diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-53 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Miscellaneous patch panel with 10 lamps, interconnection diagram 3-8 Red digital patch bay (typical), front view . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-8 Red digital test bay (typical), front view . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-9 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Red vf test bay (typical). front view 3-10 Quality assurance test center (Pentagon) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-8 Transfer of circuit to spare multiplex channel at the equal level patch panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-9 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Transfer of circuit to spare cable circuit at the primary patch panel 4-10 Substitution of line conditioning equipment using the equal level and primary patch panels. . . . . . . . . . . . . . . . . . . . . 4-11 Transfer of a Dc circuit to a spare VFCT channel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-13 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Transfer of a Dc circuit to a spare digital line interface unit (DLIU). 4-14 ........................................................... Transfer of a Dc circuit to a spare cable pair 4-21 Noise burst on multiplexed through circuit, fault isolation flow chart (sheet 1 of 2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-22 Noise burst on multiplexed through circuit, fault isolation flow chart (sheet 2 of 2).. . . . . . . . . . . . . . . . . . . . . . . . . . . 4-23 Noise burst on a local subscriber circuit, fault isolation flow chart (sheet 1 of 3) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-24 Noise burst on local subscriber circuit, fault isolation flow chart (sheet 2 of 3) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-25 ............................... Noise burst on local subscriber circuit, fault isolation flow chart (sheet 3 of 3) 4-26 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Vf subscriber circuit loop-back method, fault isolation flow chart (sheet 1 of 2) 4-27 Vf subscriber circuit loop-back method, fault isolation flow chart (sheet 2 of 2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-38 Relative envelop delay vs frequency limits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-44 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Sample distortion trend analysis chart 4-44 Sample noise level trend analysis chart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-45 Sample number of outages trend analysis chart. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-50 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Sample voice frequency circuit configuration connection diagram (sheet 1 of 3) 4-50 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Sample voice frequency circuit configuration connection diagram (sheet 2 of 3) 4-51 Sample voice frequency circuit configuration connection diagram (sheet 3 of 3) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-3 Idle channel (residual) noise test. 6-4 Frequency response test. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-5 Envelope delay distortion test. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-7 Audio frequency test. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-9 Longitudinal balance input test. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-10 Longitudinal balance output test. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-11 Single tone interface test. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-11 Conversion dBm to dBrnc0. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-13 Impulse noise test. . . . . . . . . . . . . . . . . . . : 6-14 Terminal impedance test for transmit circuit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-15 Terminal impedance test for receive circuit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-18 Harmonic distortion test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-17 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Composite signal transmission level test 6-18 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Phase jitter testing using an oscilloscope 6-19 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Phase jitter testing using a phase jitter meter 6-21 Station to station signaling test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-22 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . In-stations signaling test 6-22 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Net loss variation test 6-23 Station to station total peak and average bias telegraph distortion test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-24 In-station total peak and average bias telegraph distortion test. . . . . . . . . . . . . . . . . . . . . . . . . . . . . Located in back of manual Simplified power distribution system. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Located in back of manual Vf primary or equal level patch panel, interconnection diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Located in back of manual Primary Dc patch panel, interconnection diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Located in back of manual Dc patch panel (receive) with cut keys and lamps, interconnection diagram. . . . . . . . . . . . . . . . . . Located in back of manual Dc path panel (transmit) with cut keys and lamps, interconnection diagram . . . . . . . . . . . . . . . . . . . Located in back of manual TCF Pirmasens, signal diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Located in back of manual TM 11-5895-1012-10 Number FO-7 FO-8 FO-9 FO-10 FO-11 FO-12 FO-13 FO-14 FO-15 FO-16 Page Title Located in back of manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . TCF Pirmasens, floor plan TCF Berlin, signal diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Located in back of manual TCF Berlin, floor plan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Located in back of manual TCF Pentagon, signal diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Located in back of manual TCF Pentagon, floor plan. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Located in back of manual TCF Pentagon, QA test center floor plan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Located in back of manual Typical black digital circuit IDF connection diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Located in back of manual Universal digital patch panel, interconnection diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Located in back of manual Universal digital patch panel black send circuit strapping diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . Located in back of manual Universal digital patch panel black receive circuit strapping diagram . . . . . . . . . . . . . . . . . . . . . . . . . . Located in back of manual iii TM 11-5895-1012-10 CHAPTER 1 INTRODUCTION 1-1. Scope a. This technical manual describes a Technical Control Facility (TCF) in general terms. It addresses the purpose and function of the TCF; provides description as to how a TCF will fit into the overall Defense Communications System (DCS) and the various types of signal which could appear at a TCF’s patch panels. b. Included is a description of a typical Technical Control Facility; the off-site systems and equipment which could interface with it as well as that equipment most usually located within the TCF, and a typical test equipment load which is used for testing and troubleshooting of communications circuits controlled by the c. This technical manual also describes TCF operations which include operational practices and methods, circuit r&oration procedures, implementation of communications services requirements, typical circuit troubleshooting procedures and testing of circuit performance and quality. 1-2. Indexes of Publications a. DA Pam 310-4. Refer to the latest issue of DA Pam 310-4 to determine whether there are new editions, changes or additional publications pertaining to theequipment. b. DA Pam 310-7. Refer to DA Pam 310-7 to determine whether there are modification work orders (MWO's) pertaining to the equipment. 1-3. Forms and Records a Reports of Maintenance and Unsatisfactory Equipment. Maintenance forms, records, and reports 38-750. P4610.19C, and DLAR 4500.15. 1-4. Administrative Storage ment, refer to TM 740-90-1. 1-5. Destruction of Army Material 1-6. Reporting Equipment Improvement Recommendations (EIR) 1-7. Abbreviations 1-1 TM 11-5895-1012-10 CHAPTER 2 DESCRIPTION OF TECHNICAL CONTROL FACILITY Section I. GENERAL 2-1. Purpose f. Exercise technical direction, coordination and supervision over activation, deactivation and rearrangement of transmission facilities in accordance with directions received. g. Activate and deactivate traffic overload circuits. h. Report to DOCC and Operation and Maintenance elements the status of transmission facilities for operational direction and management. i. Substitute equipment or circuits for maintenance purposes or to isolate communications faults. j. Performs required administration and record keeping. t restoration purposes, and from service for mainteone of the tools available 2-2. Functions of a TCf The major functions of personnel assigned to a DCS Station TCF are summarized as follows: a. Coordinate with the DCA Operations Control transmission facilities and interpearing at the TCF, as well as the extension of communications facilities provided by or users of the DCS. priori& and estabdirection, coordinaout-of-service transthe DCS station. 2-3. General TCF Responsibilities Each Technical Control Facility is responsible for maintaining continuity of service through effective operation and maintenance of the DCS facilities within its operational area. This includes Patch and Test Facilities, and attended and unattended facilities. General functional responsibilities of TCF personnel include but are not limited to the following: a. Restore or reroute disrupted circuits over available facilities in accordance with the predetermined restoration priority. The technical control that first becomes aware of the outage is responsible for initiating the restoration and follow through actions concerning the restoration, until such time as service is restored. b. Report all information pertinent to an outage. c. When a disrupted segment of a circuit is on a disrupted multiplexed group, coordinate with the Facility Control Office (FCO) for that segment to determine if that segment of the multiplexed group is being restored. d. Direct localization of troubles found or reported, when necessary refer troubles to the responsible office. e. Provide progress reports, as required, in restoration activities. f. Carry out technical control functions in locating and clearing trouble in outside plant cable and facilities. g. Conduct in-service quality control tests and assist in out-of-service testing and/or circuit realignment. A. When a failure occurs on a multipoint circuit, determine and remove the affected segment. Restore the circuit in accordance with priority assignment. i. Review the temporary path change record regu 2-1 TM 11-5895-1012-10 larly. Take action to restore the circuit to its normal path. j. Notify the Circuit Control Office (CCO) when a circuit has been changed considerably or has been restored after prolonged outage so that the circuit can be retested end-to-end. k. Respond to the operational direction and technical supervision of higher level control offices. l. Consult with the higher level control office before taking action that would disrupt service, except in emergency situations when the action cannot be deferred. m. Prepare and forward reports in accordance with current directives. n. Establish written local operating procedures for coordinating with commercial agencies, users, and other sections within the DCS Station. o. Review circuit performance and initiate action with other stations to correct problems or unsatisfactory conditions. Refer conditions and problems beyond the capability or outside the authority of the TCF to the appropriate control center or operation and maintenance activity with recommendations for resolution. p. Arrange for coverage of partially attended or unattended stations when a need is anticipated or when an emergency or channel shortage arises. q. Activate on-call or overload circuits. r. Coordinate and expedite activation of special circuits called for in special instructions. s. Maintain up-to-date contingency actions to be taken in the event of significant communications failure to ensure continuity of service. t. Exercise extreme care so that service is not inadvertently interrupted. u. Report immediately all instances of negative or untimely response from PTF’s, operation and maintenance activities, other TCF’s, or commercial agencies. v. Make recommendations which would improve the TCF either as a facility or from an equipment standpoint. w. Maintain and properly label equipment and patch bays. x. Assure that all technical controllers are trained in authorized procedures and that these procedures are followed. y. Maintain a current reference library readily accessible to all technical controllers. z. Publish and post notices concerning additions, de= letions, or changes in circuits; special tests on circuits or equipment; changes in frequency assignments, etc. 2-4. TCF Responsibilities to Subscribers or Users or user access to the A TCF which provides DCS has additional responsibilities which must be satisfied. The service TCF personnel are responsible at all 2-2 have a circuit which stored or rerouted over new facilities tested from endto-end. f. Notiy the appropriate control office will not be available at the time and date tenance work, and other sched tions. 2-5. Additional Responsibilities ties at the station as follows: a. Technical Control Facility. TCF sponsible for: (5) Radiated power. (6) Transmission levels. c. Radio Receiver Station. TM 11-5895-1012-10 the identification of harmful inAssistance in the evaluation of jamming sigof incoming signals and making ons concerning frequency changes. 2-6. Special Assignments implementation of the overall control plan requires that certain TCF's be designated as Facility Control Offices, Circuit Control Offices, and Intermediate Control Offices (ICO). Control office designaCommunications based on recomand vary depending upon the length and complexity of the overall transmission facility, types of transmission media involved as well as the communications and testing facilities available. The responsibility for overall service still rests with the DOCC. However, the specially designated TCF's assist in carrying out the mis- exercises technical supervision over specified DCS wideband facilities. The FCO is selected on its accessibility to the systems and stations under its control and orderwire capabilities to each Intermediate Control Office and to other TCF's within the designated area of responsibility. When a TCF is designated as a FCO it will have technical supervision over all links under its control. All TCFs and PTF’s along the route, as well as all connected TCF's and PTF’s. These stations will respond to the FCO’s technical direction. TCF personnel assume the following added responsibilities when the TCF is designated as a Facility Control Office: n operational status of assigned facili(1) ties. (2) Direct remedial action to correct service degradations which affect system performance and user service. (3) Direct restoral and reroute action. (4) Direct special testing to isolate system and cirto determine capability of the system to or uniqueservice requirements. adjacent TCF’s and PTF’s whenever a that may have an effect on the opera- ters within established standards. (7) Establish procedures for subordinate stations to forward to the FCO test and alignment data; analyze that data looking for trends toward adverse system performance; forward performance data to the DOCC and operation and maintenance activities. (8) Implement transmission facility activation, deactivation, and configuration change schedules. Notify appropriate elements when implementation is completed or delayed. (9) Maintain appropriate logs and system performance records. (10) Report assigned facility operation status to higher levels of authority and respond to their direction. b. Circuit Control Office. One TCF through which a circuit passes is designated in the technical service order as the CCO. CCO personnel are responsible for the following actions: (1) Activation of the circuit from end-to-end and ensure that the service order is completed 72 hours before the scheduled service date. (2) Direct overall lineup and subsequent testing to ensure that the circuit meets the parameters established for the grade of service. (3) Advise the appropriate elements of any circuit restrictions which might effect service. (4) Prepare and implement out-of-service quality control test schedules. (5) Record and maintain on file the required test summary. (6) Initiate isolation and correction of any trouble discovered as a result of quality control testing. (7) Coordinate end-to-end testing whenever the circuit routing is substantially changed or it has been restored after a prolonged outage. (8) Make certain that all patches and cross-connects are removed when the circuit is discontinued. (9) Report to high level of authority, uncooperative action on the part of any TCF, PTF, or commercial agency during circuit activation or deactivation. (10) Coordinate restoration of assigned circuits including coordination of reroute action. (11) Direct and coordinate troubleshooting to isolate and clear the trouble which is disrupting service. (12) Restore the circuit to its normal path as soon as possible. This is done through constant review of temporary path changes. (13) Keep all elements advised as to progress of restoration work. (14) Establish procedures for handling and recording service interruptions and bring any conditions beyond the capability of the TCF’s, PTF's and/or CCO to the attention of the appropriate element. d. Intermediate Control office. If the circuit layout is such that the FCO or the CCO is not in the best posi 2-3 TM 11-5895-1012-10 tion to test and coordinate activities of intermediate TCF's, another TCF can be designated as an Intermediate Control Office. The ICO will be designated on the service order at the time of layout and TCF personnel have the general responsibility of the assigned segment as well as the following: (1) Conduct in-service testing and take corrective action in the case of signal degradation, including those signals not alarmed by pilot frequencies. (2) Activate, deactivate, and change the circuit in accordance with TSO's. (3) Initiate chit Section II. SYSTEM SERVICE INTERFACES AND TYPES OF SERVICE 2-7. Introduction In this section and the types technical conof service will troller to make the most efficient use of circuits and systems available, an understanding of the overall DCS and the facilities serviced is necessary. In addition to understanding the make-up of the DCS, the technical controller should be familiar with the transmission media used; communications facilities involved; the facilities which use the DCS mainline trunk routes as a transmission path; and the types of signals which are generated by these facilities. The information covered in this Election is listed below together with appropriate paragraph references: a. DCS common user network (para 2-8). b. Transmission media (para 2-9). c. Communications facilities (para 2-10). d. Relay Centers (para 2-11). e. Automatic Voice Network (AUTOVON) (para 2-12). f. Automatic Digital Network (AUTODIN) (para 2-13). g. Types of signals (para 2-14). 2-8. DCS Common User Network a A common user network is one that provides a set number of channels of voice or data communications for use by an even larger number of users on a shared basis. A user of a communications network can be a person making a telephone call; a communications center originating or receiving many teletype messages, data or facsimile signals; or a solitary teletypewriter maintaining contact with another like machine. The originating user am be linked to another activity within the same geographical area or in another geographical area. The point to remember is that the available channels of communications are shared by all or they are for "common usage”. Within the DCS the majority of the available channels are for common usage. Dedicated circuits, which make up the remaining channels, are established to support the traffic originating at dedicated facilities which provide communications of common interest, high volume, or priority traffic cus2-4 2-9. Transmission Links and Media (1) High Frequency Radio. This media can cover TM 11-5895-1012-10 Figure 2-1. Example of a world-wide common user network. 2 - 5 TM 11-5895-1012-10 distances up to 6,000 miles. The ground distance between stations is dependent upon the equipment selected and station design. A limitation on high frequency radio is the small number of multiplexed channels which can be carried, usually 4 voice frequency (2) Line of sight Radio. These radio links operate in the very high frequency, ultra high frequency or microwave frequency regions. There must be 8 line of sight path between the transmitting and receiving stations, however, this limitation is overshadowed by the capability of such links carrying a high density of multiplexed communications channels. (3) Tropospheric Scatter Radio. This type of media relies on the forward scatter technique or propagation. Tropospheric scatter can cover distances between 100 to 500 miles and carry a large number of multiplexed channels, depending upon system design. This media of transmission is also referred to as overthe-horizon propagation and does not require a line-ofeight path between stations. (4) Satellite Radio. The distances covered by this media depends upon how high above the earth the satellite relay station is positioned. The distance between earth stations usually vary between 2,000 and 6,000 miles. The transmission link is capable of carrying many multiplexed channels. The main limitation is that the channel capacity and position of the satellite relay station cannot be upgraded or changed. (5) Metallic Links. Metallic links can be coaxial cable, paired cable, or open wire. A metallic link can be of all one type or by use of interfacing equipment be a mixture of two or all three of the types. A metallic cable link can be either submarine or landline. Metallic systems can carry a low density or a high density of multiplexed channels depending on the equipment and the type of cable selected and user requirements. The major limitation is in the construction of such systems. Right-of-way must be arranged and cable or wire laid to make the physical connection between the two breakout points. An added factor is the maintenance, and when needed, the repair of the outside plant facilities. b. Transmission links utilizing line of sight paths, tropospheric scatter, and metallic media can cover the required distance between breakout points directly or may require intermediate stations to span the distance between the two stations providing the breakout capability. These intermediate facilities are called relay stations for radio systems and repeater stations for metallic systems. In either case the relay or repeater station performs the same function It will equalize and simplify the incoming signals to permit the retransmission of a signal that, as near as possible, duplicates the original transmitted signal. c. Referring to figure 2-1, the common user net2-6 work depicted can be made up of all the types of tram mission media described above. In addition, any one or all of the transmission links shown could have one or mom intermediate relay or repeater stations as part of the link, or span the distance without the need of these stations. The type of equipment selected and the make up of the transmission link is determined by the distance between breakout points, strategic and economic factors, and the technical parameters required to provide the appropriate type and grade of service to the users. 2-10. Communications Facilities (fig. 2-2) The communications facilities, which when connected together to form the worldwide common user system can be classified as tributary stations, major relay stations, or minor relay stations. a. Tributary Stations. A tributary station provides communications services, telephone, teletype, data etc., to activities located at the same base or installation. It is not a requirement that tributary stations be located on a base or installation. It could be positioned in a civilian community where there is a concentration of DCS users. The equipment installed at the tributary station is compatible to that of the relay station or message switching center that provides access to the DCS. In figure 2-2, the facilities located at Camp P and Camp J, are tributary stations located on the in stallation. From the tributary station, lines extend outward to the user equipment. This equipment can be a single teletypewriter; banks of teletypewriters located in the installation communications center; data terminals; a computer; a facsimile machine; and the installation telephone exchange. The telephone exchange further extends the service of the tributary station to each authorized telephone user on the installation. Stations PDQ and LMN are tributary stations not located on an installation, but in a town or city in which there are a number of authorized users requiring access to the DCS. The transmission link between the tributary station and its associated access station to the DCS can be direct or require the use of repeater or a relay station. b. Major and Minor Relay Station Tributary station access to the DCS is through a relay station, Traffic flows through the access relay station onto the system to the distant tributary station. Relay stations are classified as major or minor depending upon their` position in the DCS. (1) Major Relay Station. In figure 2-2, DCS Station ABC can be classified as a major relay station. It is situated at a nodal (or junction) point of two or more DCS subsystems. In addition to passing traffic originating at or destined for a connected tributary station, it also acts as a circuit switching station. The TM 11-5895-1012-10 Figure 2-2. Interconnection of communications facilities, simplified diagram. 2-7 TM 11-5895-1012-10 station is located at the junction of Government owned Systems #1, #2, and #3 of the world-wide network, and is also an access point to leased circuits carried over a commercial facility, and a Government owned satellite system. Signals entering ABC on System #3, as an example, from tributary station LMN or beyond DCS Station XYZ, and not destined for a connected tributary station, would be switched to leave the nodal point on Government System #1 or #2, the commercial facility, or the Government satellite system. The switching can be accomplished on a channel, group or supergroup level. DCS Station ABC provides many routing capabilities for signals originating at an associated tributary station, including interconnection of users located at any of the serviced tributary stations. (2) Minor Relay Station. DCS Station XYZ (fig. 2-2) can be classified as a minor relay station. The amount of installed equipment would be much less than that of DCS Station ABC since it is not at a nodal point. It services only one tributary station, and provides access only to the East or West on System #3. Message Relay Center Interface (fig. 2-3) It is not feasible (economically or practically) to have each teletypewriter user connected directly to every other users machine. Economic interconnection is established through a complex subsystem network of message relay centers. The worldwide DCS is used as the vehicle to transmit messages from one user to another. Individual teletypewriter signals are multiplexed into composite signals which are then transmitted over the DCS system voice channels. So that every teletypewriter user can transmit to any other user, a system of message relay centers has been established to switch (or relay) the messages from one system to another and move it from the originator to the addressee as quickly as possible. The message relay center may be an activity serviced by a tributary station or a tributary station itself. Message relay centers are classified into three categories: manual, semiautomatic, and automatic. a Manual and Semiautomatic Message Relay Centers. The manual and semiautomatic message relay centers employ the torn tape method of operation. An operator tears the incoming message tape off of a receiving machine, reads the routing indicator, and hand carries it to the transmitting position. This is a relatively slow method since the speed of passing a ge tape through the office is dependent upon the and accuracy of the operator in reading the rout+ ing indicator, carrying it to the transmitting position, and preparing it for retransmission. The semiautomatic message relay center speeds up the retransmission process by having an automatic numbering process and tandem transmitter distributors with auto2-11. 2-8 matic switching between them. b. Automatic Message Relay Centers. There is no need for operator intervention during normal operation of this type of message relay center. Messages am automatically passed, via cross office equipment from the receiving machine to the transmitting position, renumbered and retransmitted to the next relay center or to the addressee. This permits rapid relay of messages through the relay center. Delay is only dependent upon the speed at which the cross-office equipment operates. So that this facility can operate at maximum speed and efficiency, there is a need to maintain precise accuracy in the production of the original message tape, and high quality of the DCS circuits over which the message travels. 2-12. AUTOVON INTERFACE (fig. 2-3) a. The worldwide DCS main-line trunk routes pm vide the transmission path for voice frequency communications over the Automatic Voice Network (AUTOVON) another DCS subsystem. The basic objective of AUTOVON is to establish a common-user automatic switching network that provides worldwide compatibility, reliability, flexibility, and greater survivability of telephone communications. The voice communications capability is provided between Department of Defense users and between Department of Defense users and certain non-DoD users. The system is established primarily for voice communications, but it is capable of handling graphic and data transmissions on a user-to-user basis. It is capable of handling secure communications when the appropriate equipment is installed at user locations. For operational and control purposes, the AUTOVON switch has a built-in TCF which functions as a tributary station to a DCS major or minor relay station. b. The Automatic Voice Network is intended to offer identical services worldwide to its users. Services that are available to users system wide are as follows: (1) Normal Service. It provides the capability for direct dialing from one user to another on a worldwide basis. In instances where limited trunking facilities are available, the user will place the call through a local operator or a Dial Service Assistant. (2) Four-Wire Service. Selected subscribers to AUTOVON are provided with a special I-wire telephone for direct access to the network. Data subscribers are provided access to specially conditioned AUTOVON data circuits. The signalling from a 4wire instrument is dual-tone, multifrequency. The four-wire service subscribers can also be provided with up to three levels of precedence for pre-emption of lower level precedence calls when necessary. (3) Off-Hook Service. The off-hook service sub scriber is immediately connected through the network TM 11-5895-1012-10 Figure 2-3. Subsystem interface with the DCS. to a predesignated subscriber as soon as the handset is lifted from the cradle. (4) Special Networks. These special networks may allow complete privacy to specially designated users or allow them access to the entire AUTOVON network. These special networks fall into two categories: (b) Category 2 provides special treatment to users within a special interest community. This community of special interest can be within one geographical area or worldwide. General purpose subscribers can be prevented from calling into category 2 networks and category 2 subscribers can be denied access to the general purpose network. c. Normally connection through the AUTOVON from user to user will be completed in about 4 seconds. Difficult connections may take up to 10 seconds through unusual or complex routing. This is switching time only and excludes the time required to dial. Offhook service connections are normally established in less than 2 seconds. So that designed speed and quality of service can be realized, AUTOVON designated DCS circuits must be maintained at a high quality. 2-13. AUTODIN Interface (fig. 2-3 and 2-4) a Another communications subsystem interface which a technical controller must be aware of and familiar with is the Automatic Digital Ne (AUTODIN). AUTODIN interstation trunks are sup plied by the worldwide DCS main-line trunk routes. The transmission quality on the AUTODIN trunks is the responsibility of the DCS Station Technical Control Facility. The technical control personnel monitor all incoming dc circuits and breakdown voice frequency telegraph carrier into individual dc circuits. These circuits are then extended to the AUTODIN switch. Like the AUTOVON, the AUTODIN Switching Center has a built-in Technical Control Facility for operational and control purposes. b. AUTODIN Is a store and forward switching network for the transmission of digital data. The AUTODIN is a high speed, flexible, computer controlled network which provides the Department of Defense and other Government agencies with digital communications. The flexibility of AUTODIN is illustrated by the following capabilities: (1) Processes traffic on a store and forward basis between two widely separated users. (2) Sends and receives traffic to and from users at transmission rates between 75 and 2400 baud and between AUTODIN switching centers at rates up to baud. (3) Accepts traffic from teletypewriter, punched card terminals, magnetic tape terminals, and computers. 2-9 TM 11-5895-1012-10 Figure 2-4. AUTODIN interface with the DCS. 2-10 TM 11-5895-1012-10 (4) Exchanges traffic between users whose equip ment operates at different speeds and use different codes and formats. c. The AUTODIN interface with a DCS Station is illustrated in figure 2-4. AUTODIN tributary stations are connected to the AUTODIN Switching Center (ASC) directly or via AUTODIN conditioned trunks of the Automatic Voice Network (AUTOVON). The ASC is connected for transmission to another ASC via the DCS Station which acts as the gateway to the DCS. The traffic is cleared through the station and routed out on predetermined and preconditioned circuits over cable, radio, or satellite systems. These circuits can be over Government owned facilities or over leased facilities. d. The AUTODIN Switching Center can be connected to another ASC over the AUTOVON as a primary route or, in the event of a failure of a primary route, as a backup circuit through the establishment of on-call patches. In addition, users of AUTODIN who do not require full time access to the ASC can be connected to the switching center over AUTOVON on a call-up basis. In cases where AUTODIN is routed over AUTOVON for restoral or for non-full period users of the AUTODIN to gain access to the ASC, it is the responsibility of the technical controller at the ASC to establish the path. The controller dials up the distant ASC or user, establishes voice contact, makes the required equipment connections to the circuit, and then turns the circuit over for digital communications. After restoral of normal routing or at the end of the user real-time schedule, the originating technical controller coordinates the release of the called-up circuit. 2-14. Types of Signals A technical controller can expect to find signals from any type of terminal equipment passing through the TCF. The signals from these equipments include but are not limited to dc teletype loops, speech, data, facsimile and voice frequency carrier telegraph (VFCT). The signals may be broken down to a channel level or pass through the Technical Control Facility at the group or supergroup level. The terminal equip ment generating the data, facsimile and VFCT signals, produce a composite tone in the voice frequency range and the tones are then normally transmitted over a voice frequency channel that has a range from 300-2800 Hertz (Hz) (2500 Hz bandwidth, (nominal 3 kHz channel)) or 300-3400 Hz (3106 Hz bandwidth (nominal 4 kHz channel)). There are some instances, such as with television or other wideband signals, where the composite tones require a wider bandwidth. In these cases two or more adjacent channels are specially prepared for transmission of the wideband signal. a. The voice frequency speech signals can originate from 2-wire or 4-wire instruments with almost any type of signaling, The power for this circuit is generated as the user speaks into the telephone and the frequency complexity of the signal is that of ordinary speech. b. DC teletype signals originate at the teletype machine and consists of a series of coded pulses, (each one unique to a keyboard character) where a direct current is either flowing or not flowing. The teletype signal can be passed through the station as dc to another teletypewriter, but most usually it is inputed to voice frequency carrier telegraph equipment where the pulses generate tone signals for one channel of the VFCT composite output tone. c. Voice frequency carrier telegraph systems accept from 2 to 16 or more teletypewriter signals and multiplexes the tones generated by each teletype signal into a composite “tone package”. Each teletypewriter signal occupies a different portion of the frequency spectrum of the tone package, which is then transmitted over a single voice frequency channel. d. Data and facsimile terminal equipment functions in the same manner as a VFCT terminal. In converts the intelligence from mechanical linkage or light intensity into a unique data stream or series of tones which can then be transmitted over a single voice frequency channel. Data signals can originate at a single data terminal or from an AUTODIN Switching Center. e. At the Technical Control Facility the controller monitors and tests these signals at the voice frequency level, except in those instances where a dc teletype loop appears at a dc patch panel. Various types of test equipment, which will be discussed later, are available for the technical controller to check the quality and level of the signals passing through the station. Section III. THE TECHNICAL CONTROL FACILITY 2-15. General a. The Technical Control Facility (fig. 2-5) is that element of a communications network that provides the technical control, interfaces transmission elements of the DCS, and interfaces the user with the System. The management of the communications paths is done at the TCF and subordinate Batch and Test Facilities. As noted in the previous section, the communications paths can be over any of the following transmission media singly or in serial combinations: (1) Submarine cable. (2) Land-line cable or wire circuits. (3) High frequency radio circuits. (4) Tropospheric scatter radio circuits. 2-11 TM 11-5895-1012-10 (5) Line-of-sight radio circuits. (6) Earth satellite radio circuits. b. The Technical Control Facility functions to provide technical direction, coordination, technical supervision of transmission media and equipment, quality control, communications restoral and status reporting. These functions are accomplished with the following five basic operations: (1) Patching (r&oral, test, monitor). (2) Coordination (to far-end, to user, to maintename). (3) Testing (insertion of a known signal with measurement for frequency, level, distortion, etc. on an out-of-service basis). (4) Monitoring (measurement of existing circuit conditions or traffic, without insertion of a test signal, on an in-service basis). (5) Reporting (circuit and system status to users, adjacent TCF’s, circuit distant end, operation and maintenance activities, etc., as well as all required repetitive reports). c. Normally, the TCF is collocated with a tape relay and switching center, and/or a carrier terminal facility, but it may be located with either a radio station or telephone facility. The choice of location is usually based on a study of all factors involved in site selection. By choosing to collocate the Technical Control Facility with the tape relay or switching facility eliminates the necessity of providing additional intrastation links. All circuits, regardless of the media used and type of signal, are available at jack appearances at the TCF. These appearances provide the flexibility required by a TCF. There are exceptions to this rule where circuits transit the station on a through group level. However, there are group access points, which allows access to the circuits being carried on a through group for testing purposes. These access points normally located at the multiplex equipment outside the TCF, can also be used as patching points for restoral or rerouting of groups in the event of system failure. 2-16. Technical Control Configuration Block Diagram (fig. 2-6 and 2-7) a. General. The block diagram illustrates the interrelationship among the major equipment of the Technical Control Facility together with the terminal equipment. Although the Technical Control Facility of many DCS Stations may not require access to all transmission modes shown in figure 2-6, the TCF configuration should be essentially the same, whether the station is located at a transmission nodal point or terminal point. The block diagram includes all major equip ment and patch facilities which are involved in the overall technical control function, however, all items will not necessarily be located with the immediate TCF 2-12 operating space, as indicated on the diagram. Figure 2-7 shows a typical floor plan for a Technical Control Facility. b. Primary Patch Bay. (1) Dc and Digital. The dc and digital primary patch bays are those areas within the TCF where dc and digital user circuits can be patched, monitored and tested. Signals may be high or low level and baud rate depending on the user terminal equipment. (2) Voice Frequency (VF). The vf primary patch bay is that area within the TCF where voice frequency circuits can be patched, monitored and tested. Signal will have varying levels and signalling schemes depending on the user terminal equipment. c. Circuit Conditioning Equipment. Circuit conditioning equipment, such as amplifiers, pads, hybrids etc., signalling equipment, digital line interface units (DLIU), and circuit ancillary equipment is so installed and wired into the TCF so that it will appear between the primary and equal level patch bays. d. Equal Level Patch Bay. The equal level patch bay is that area within the Technical Control Facility where voice frequency channels at the standard Test Level Point (TLP (OdBr send and receive)) utilizing standard in band signalling can be patched, monitored and tested. e. Group Patch Bay. The group patch bay is that area where multiplexed groups (usually 12 channels can be patched, monitored, and tested. f. Coaxial Patch Buy. The coaxial patch bay is that a associated with the TCF where signals requiring distribution via coaxial cable can be patched, monitored, and tested. Signals which require coaxial cable distribution include supergroup, baseband, high speed Time Division Multiplexed signals, etc. g. Dc Circuit Bay (Low/Level) and Digital Patch Buy. The dc circuit and digital patch bays are those areas within the Technical Control Facility where low level analog or digital data circuits can be patched monitored and tested h. Patch Panel Appearances. Patch panel appear ances are furnished and installed for the following (1) Allow for substitution for those units which are out of service because of test and maintenance of the facility. (2) Allow for substitution of equipment strings (circuit or wideband segments) as they occur between the primary and equal level patch panel appearances. i. Time Division Multiplexer Equipment (TDM). The time division multiplexer equipment is a technique to accept various digital signals (both data and teletype) with different bit rates and combine them into a single high bit rate stream for transmission. The demultiplexer section reconstructs the signals at the same nominal rate at which they entered the multiplexer This equipment can be used in tandem to accommo- TM 11-5895-1012-10 Figure 2-5 Technical Control Facility, interface diagram. 2-13 TM 11-5895-1012-10 Figure 2-6. Technical Control Facility, configuration block diagram. 2-14 TM 11-5895-1012-10 date a wide range of data rates to produce a single serial stream of information, with its associated timing. j. Pulse Code Modulation Equipment (PCM). The pulse axle modulation equipment normally accepts the analog signal (the modulating signal) and samples it at a predetermined rate. The sample is then quantized and coded so that each element of information consists of differing numbers of pulses (marks and spaces). This equipment generally uses an eight bit sample rate. k. Modems. (1) Digital Modems (VF). This is a modem which is used to convert direct current signals appearing on the digital patch bay to the analog form for appearance on the equal level patch bay. This equipment requires a nominal bandwidth of 4 kHz (2) Special Digital Modems (Group). Input to this modem is in digital form from the digital patch bay. Its output is analog form and appears on the group patch bay in the standard frequency division multiplexed group frequency bandwidth of 60 to 108 kHz. (3) Special Modem (Supergroup). Input to this modem is in digital form from the wideband user/switch or TDM. Its output in analog form appears on the supergroup portion of the coaxial patch bay in the standard FDM supergroup frequency bandwidth of 312 to 552 kHz. 2-17. Voice Frequency Circuits a. General. All voice frequency (vf) users including AUTOVON, AUTODIN, and AUTOSEVOCOM switches, communications centers, PABX's, local switchboards and tactical multiplex equipment access the TCF by way of the Primary Patch Bay. Four-wire fixed station multiplex equipment utilizing 2600 Hertz signaling access the TCF by way of the Equal Level Patch Bay. All conditioning and signalling equipment required to achieve compatibility between users and the transmission media is electrically connected between the Equal Level Patch Bay and the Primary Patch Bay. The Primary Patch Bay terminates 2, 4, 6, or 8 wire user circuits. The Equal Level Patch Bay serves at the principal point of interface and restoration in the Technical Control Facility. Circuits appearing at the Equal Level Patch Bay appear as 4-wire balanced pair circuits (AUTOVON switch circuits having Pilot Make Busy capability appear as five-wire circuits). The Equal Level Patch Bay is the zero (0) test level point in the station, that is, OdBr send and receive. DCS standard supervisory signals appear as 2600 Hertz tones at the Equal Level Patch Bay. b. Circuit Descriptions. The following is a list of the various types of voice frequency circuits which may be commonly found appearing in the Technical Control Facility. A TCF may service other circuits which are not included in the following list. A description of each circuit follows in the paragraph indicated. (1) Two-wire voice user with 20 Hertz signalling (para c below). (2) Two-wire voice user with loop signalling (para d below). (3) Two-wire voice user with E&M signalling (para e below). (4) Two-wire voice user with standard integral signalling (para f below). (6) Four-wire user with standard integral signalling (para g below). (6) Four-wire user with 20 Hertz signalling (para h below). (7) Four-wire user with loop signalling (para i below). (8) Four-wire data user cable to TCF (para j below). (9) Two-wire or four-wire voice user using nonstandard in-band signalling (nonstandard signalling unit at user terminal) (para k below). (10) Four-wire user with DX signalling (para l below). (11) Four-wire PBX trunk to AUTOVON (PBX cable to TCF) (para m below). (12) Four-wire data user with DX signalling (para n below). (13) Two-wire PBX cable access line (two to four wire conversion at PBX) to local AUTOVON switch (para o below). (14) Four-wire AUTOVON subscriber telephone cable to TCF (loop resistance less than 700 ohms) (para p below). (15) Four-wire AUTOVON circuit (remote twowire PBX subscribers) (para q below). (16) Four-wire AUTOVON special grade circuits (AUTOVON subscribers (data) and inter-switch trunks) (para r below). (17) Four-wire AUTOVON voice grade circuits (para s below). (18) Voice and telegraph users connected to High Frequency radio transmission media (pars t below). (19) Four-wire voice frequency carrier telegraph (para u below). (20) Fixed station multiplex interconnection (para v below). (21) Non-DCS multiplexer user to DCS user on base, or using DCS transmission media (para w below). (22) Four-wire entrance toll cable (para x below). (23) Four-wire connections to High Frequency radio systems (para y below). c. Two- Wire Voice User With 20 Hertz Signalling (fig. 2-8 ). The users for this circuit are either a two-wire switchboard or an individual two-wire user using 20 Hertz ringing source. This circuit provides echo suppression and control in order to minimize 2-15 TM 11-5895-1012-10 Figure 2-7. Technical Control Facility, typical floor plan. 2-16 TM 11-5895-1012-10 Figure 2-81. Typical voice frequency circuits (sheet 1 of 5). 2-17 TM 11-5895-1012-10 Figure 2-82. Typical Voice Frequency Circuits (sheet 2 of 5) 2-18 TM 11-5895-1012-10 echoes arising from four-wire to two-wire conversions. The circuit makes an appearance at the Primary Patch Bay by way of outside plant cables. Between the Primary and Equal Level Bays, conditioning is provided by pads, amplifiers, and two-wire/four-wire terminating sets. Signalling conversion is provided by E&M/20 Hertz converters and 2600 Hertz signalling unit. This configuration can apply to “hotline” or dedicated circuits, orderwires, and switchboard trunk circuits. d. Two-Wire Voice User With Loop Signalling (fig. 2-8 ). The users for this circuit a either two-wire switchboards or two-wire individual users which use loop signalling. The circuit is the same as that in c above with the exception of using E&M/dial loop signalling converters instead of E&M/20 Hertz convert ers. e. Two-Wire Voice User with E&M Signalling (fig. 2-8 ). The user for this circuit is either a two-wire mitchboard or individual user with E&M signalling. It is noted in this circuit that a separate cable is used in the on-base cable to carry the E&M (dc) lea& from the user location through the Primary Patch Bay to the SF 2600 unit. Conditioning items are two wire/four-wire terminating set, repeat coil, echo sup pressor, and pads and amplifiers for level adjustment. These configurations have applications as user to central officer inter-connections and user-to-user link. f. Two-wire Voice User with Standard Integral Signalling (fig. 2-8 ). The user of this circuit is a two= wire w who has 2600 Hertz inband signal incorporated into the terminal telephone equipment. A two wire/four-wire terminating set performs the necessary hybrid functions, and pads and amplifiers are installed for level adjustment. This circuit is for special application to users with this requirement and may have an echo suppressor added if so specified. g. Four-Wire VF User with Integral Signalling (fig. 2-8 ). This user provides his own 2600 Hertz inband signalling at the user station or the circuit may be a data circuit. In any cam, no signalling conversion is required at the Technical Control Facility. Between the Primary and Equal Level Bay appearances, repeat coils, pads, and amplifiers are supplied for conditioning and level adjustment Amplitude equalizers may be required depending on the service. h. Four-Wire VF User with 20 Hertz Signalling (fig. 2-8 ). The users for this circuit are either a fourwire switchboard or an individual four-wire user which uses 20 Hertz signalling. A four-wire physical circuit is used for the on-base cabling. Conditioning between the Primary and Equal Level Bays consists of pads and amplifiers for level adjustment. E&M/20 Hertz converters and SF 2600 units are required for telephone signalling conversions. This configuration can be applied to dedicated lines, and orderwire circuits. i. Four-Wire VF User with Loop Signalling (fig. 2-8 ). The users of this circuit can be either a fourwire switchboard or individual user which uses loop signalling. The circuit flow is the same as in h above except that an E&M/DC loop converter is used instead of an E&M/20 Hertz converter. j. Four-Wire Data User Cable to TCF Without Signalling (fig. 2-8 This circuit is for high speed data users, AUTODIN interswitch trunks, and data lines for secure voice circuits. In addition to level adjustment, amplitude or delay equalization units may be required in the strings of conditioning equipment. k. Two-Wire or Four-Wire Voice User Using NonStandard Inband Signalling (fig. 2-8 ). After entering the TCF by way of the Primary Patch Bay, the non-standard inband signalling is converted to standard inband signalling before it appears at the Equal Level Bay. This is accomplished by using a signalling unit compatible to the non-standard inband signal being received, converting it to E&M signalling, and applying the E&M pulses to the SF 2600 unit through a pulse link repeater. l. Four- Wire PBX or User with DX Signalling (fig. 2-8 ). The users for this circuit are either au AUTOVON PBX access line or an AUTOVON fourwire user. DX-1 signal units and repeat coils are used at the user locations either to conserve cable pairs or where loop resistance exceeds 50 ohms. If the AUTOVON switch is off base, the circuit proceeds to the Equal Level Bay with the necessary conditioning and telephone signal conversion units located between the Primary and Equal Level Patch Bay appearances. If the AUTOVON switch is collocated on-base, the circuits do not access the Equal Level Patch Bay, but after passing the Primary Patch Bay, the circuits are conditioned for proper levels and E&M signalling, and make another appearance at the Primary Patch Bay and connect to the AUTOVON switch. m. Four- Wire PBX or User with E&M Signalling to AUTOVON (PBX Cable to TCF) (fig. 2-8 ). This user circuit is similar to the circuit described in l above except there is no requirement for DX-1 signal units at the user or the TCF. This is because the user and TCF are closely located and plant cable pairs with less than 50 ohms loop resistance can be used. n. Four-Wire Data User With DX Signalling (fig. 2-8 ). This circuit is similar to makeup to that discussed in l above, with necessary amplitude or delay equalization devices. The circuit is of high speed data quality but can be called up by way of the AUTOVON switch when required. o. Two-Wire PBX Cable Access Line to Local AUTOVON Switch (Two to Four-Wire Conversion at the PBX) (fig. 2-8 ). This circuit involves connection of a two-wire on-base telephone switchboard to an AUTOVON switch which is also located on the same base. This PBX (access circuit appears only on the Pri2-19 TM 11-5895-1012-10 Figure 2-83. Typical Voice Frequency Circuits (sheet 3 of 5) 2-20 TM 11-5895-1012-10 Figure 2-84. Typical Voice Frequency Circuits (sheet 4 of 5) 2-21 TM 11-5895-1012-10 mary Patch Bay and does not access the Equal Level Patch Bay as the circuit involved does not go off base. A two-wire/four-wire terminating set shall be required at the PBX location. Normally the E&M leads will be extended as shown in figure 2-8 and described in e above. Where the loop resistance exceeds 50 OHMS, signal extension units (DX) shall be required at the PBX location and at the Technical Control Facility. Split controlled echo suppressors, pads and amplifiers when required are inserted into the circuit as shown. p. Four-Wire AUTOVON Subscriber Telephone Cable to TCF (Loop Resistance Less Than 700 Ohms) (fig. 2-8 ). This AUTOVON telephone is located less than 700 ohms from the collocated TCF and AUTOVON switch. In this case the circuit accesses the Primary Patch Bay, connects to repeat coils and level adjustment equipment, and returns to the Primary Patch Bay with E&M lead appearance and then proceeds to the collocated AUTOVON switch. q. Four-Wire AUTOVON Circuit (Remoter TwoWire PBX Subscribers) (Fig. 2-8 . This trunk circuit originates at the AUTOVON switch collocated with the Technical Control Facility. The circuit interconnects at the Equal Level Patch Bay to transmission media for service to remote two-wire PBX AUTOVON subscribers. provision is made for an echo suppressor when the PBX is two-wire. This circuit appears on the Equal Level Patch Bay and pads and amplifiers are provided for level adjustment. As this circuit is designated to interconnect with multiplex facilities, a pilotmake-busy (PMB) circuit is used as follows: (1) The Group Pilot Control (GPC) alarm circuit furnishes output leads (one for each channel in the associated group) which are grounded when group failure occurs. The GPC alarm indicates normal operation with an "open" circuit condition. (2) On each channel associated with group using the GPC alarm function, the GPC alarm leads are extended to the sleeve conductor of the associated Equal Level Patch Bay channel line jack. (3) On each AUTOVON trunk circuit the input to the sleeve conon the Equal Level Patch Bay equipment jack. The coil of the PMB relay has sufficient voltage connected to it to operate the relay when ground is applied to the GPC output lead. (4) The PMB relay operates as follows: (a) Open the E lead connection from the SF unit y after the alarm condition 50 seconds depending upon conductor to the Pri- 2-22 (AUTOVON Subscribers (Data) and Inter-Switch Trunks) (Fig. 2-8 ). This circuit operates the same as that described in q above except that delay equalization devices are provided for data use. s. Four-Wire AUTOVON Voice Grade Circuit (Remote AUTOVON Four-Wire User) (fig. 2-8 ). This circuit operates the same as that described in q above except that the circuit connects to remote AUTOVON four-wire users. t. Voice and Telegraph Users Connected to High Frequency Radio Transmission Media (fig. 2-8 Voice and telegraph using high frequency radio transmission for long distance communications accesses the Primary Patch Bay of the Technical Control Facility as audio or dc circuits. The circuits shown illustrate the setup for high frequency independent sideband transmission made up of four 3-kHz bandwidth channels. The typical four channel system depicted is equipped for three voice channels (A2, B1, B2) and one VF tone package consisting of 16 date channels (Al). Line conditioning equipment for these circuits before they access the Equal Level Patch Bay includes: a telephone terminal set or channel for each of the three voice circuits and regenerative repeaters and/or isolation relays for the dc circuits. Separate pads and/or amplifiers are provided for the VF tone package before it accesses the Equal Level Patch Bay. u. Four-Wire Voice Frequency Carrier Telegraph (VFCT) Packages (fig. 2-8 ). This circuit consists of multiple teletypewriter signals which enter the Technical Control Facility at the Primary and Dc Patch Bays and are then combined into a "tone package” at a voice frequency carrier telegraph (VFCT). The VF tone package employs a nominal 4-kHz channel bandwidth and appears at the Equal Level Patch Bay as an audio signal. Although VF level control can, in most cases, be achieved by the VFCT equipment, pads and amplifier may be installed in the circuit prior to accessing the Equal Level Patch Bay, if necessary. v. Fixed Station Voice Frequency Multiplex Interconnection (fig. 2-8 ). This is the normal configuration of a frequency circuit between the Equal Level Patch Bay and the fixed station multiplex equip ment. The only interface requirements are level control and the PMB circuit which is described in q above. w. Non-DCS Multiplex Users to DCS User On-Base or Using DCS Transmission Media (fig. 2-8 ). This circuit is provided to interface a tactical multiplex using a non-standard method of telephone signalling to user circuits conditioned for the standard signalling interface at the Equal Level Patch Bay. After an appearance at the Primary Patch Bay, a signal converter compatible with the signal used by this multiplex is installed to change the nonstandard tone signal to E&M type of supervision. These dc signals are converted to single frequency tones by a signal frequency unit; a TM 11-5895-1012-10 Figure 2-85. Typical Typical Voice Frequency Circuits (sheet 5 of 5) 2-23 TM 11-5895-1012-10 pulse link repeater may be required far transposition of the E&M leads. Level control is maintained, as required, by pads and amplifiers as indicated. x. Four-Wire Entrance Toll Cable (Fig. 2-8 This circuit is required for interconnection at the Primary Patch Bay with any long distance physical commercial toll circuit. Level adjustment using pads and amplifiers is located between the Primary and Equal Level Patch Bays. y. Four-Wire Connections to High Frequency Radio Systems (fig. 2-8 ). The remote high frequency radio transmitter and receiver sites may access the Technical Control Facility by either microwave radio or cable intersite links. Since the send and receive channels are one-way and receiving combining is used on the carrier telegraph system, all channels access the Primary Patch Bay regardless of the intersite transmission media. Similar connections are made for these channels with pads and amplifiers for level adjustment, before the circuits access the Equal Level Patch Bay. 2-18. Digital Data Circuits Existing digital dc circuits consist of a wide variety of modulation rates, modes of operation, unit codes, and circuit configurations. The variety of circuits and various equipment arrangements at the user end has caused nonstandardization of dc Technical Control Facilities. a. Signal Levels. All dc circuits appearing at the dc Equal Level Patch Bay are configured for low-level polar operation. (1) Only low-level operation is used within the black patch, test, or conditioning equipment area within the TCF. Only low-level operation is used within a red equipment area when such an area is required to support the TCF. All teletype and data end equipment used within the Technical Control Facility is configured for low-level operation in order to provide flexibility during equipment substitution and to facilitate conversion to encrypted operation at a later date. (2) Unencrypted data orderwire and reporting circuits may be required at some locations. These circuits are intended for encrypted service at a later date and are configured and routed in-station so that installation of the cryptodevice will not require major rewiring of the circuit. b. Basic User Circuits. The total user requirements are reducible to four basic types, allowing simplicity and standardization, at the digital dc patch panel and improve efficiency. The four basic types of user-access circuits described below are shown in figure 2-9. (1) Digital Data User-Access Circuits Via Dc Transmission Mode. All user-access lines entering the Technical Control Facility by way of the dc transmission mode makes an appearance on the dc portion of 2-24 the Dc Primary Patch Bay. The signal from the Dc Primary Patch Bay, if nonstandard or if isolation is required, is converted to standard low-level and then accesses the Dc Equal Level Patch Bay. (2) Digital Data User-Access Circuits Via VF Transmission Mode. All user-access lines entering the TCF by way of VF transmission mode is treated as a VF circuit until converted to standard polar dc signals. The standard low-level polar dc then accesses the Dc Equal Level Patch Bay. At this point the dc circuit is either looped back to the local user or reconverted to voice frequency for transmission over long haul transmission media. (3) Technical Control Access Digital Data Circuits. All TCF dc circuits (teletype orderwires, report+ ing circuits, etc.) appear directly at the Dc Equal Level Patch Bay. (4) High Speed Data. All high speed (above 1200 baud) dc circuits except those requiring coaxial type wiring access the Dc Equal Level Patch Bay directly without prior access through the Digital Line Interface Unit. All high speed dc line outputs and modems pm vide the standard low-level polar signal. c. Timing, Control, and Alarm Circuits. Provisions are made on the Dc Equal Level Patch Bay for patching and testing of all timing, control, and alarm circuits. d. Testing of Dc Signals. All dc circuits appear at the Dc Equal Level Patch Bay. Dc signals which appear at the Dc Primary Patch Bay will differ in coding schemes and baud rates. Testing of all dc circuits will be performed on a high impedance basis. Signal levels applied to the high impedance test equipment in all cases are equal no matter what the coding scheme or baud rate. 2-19. Wideband Facilities (fig. 2-6) a. General. Facilities for monitoring, testing, and patching of wideband circuits, multiplex groups, supergroups, and basebands are provided at stations where required as outlined below. Wideband jackfields, in bays separate from VF and dc jackfields are provided for this purpose. (1) Wideband circuit monitoring and testing facilities are provided at all stations which control such stations. At stations where alternate routes or spare equipment for such circuits are available, patching facilities to permit reroute or restoral is also included within the TCF. (2) Group, supergroup, and baseband monitoring, testing, and patching facilities are provided at all stations having more than two multiplex link terminals, and are sometimes provided at smaller stations to meet special requirements. Normally, at stations having only one or two multiplex link terminals, the jack TM 11-5895-1012-10 Figure 2-9. Standard dc/data access circuits multiplex equipment is adequate rgroup, and Group Patching Con(1) The capability for patching among like and un- of group or supergroup connectors is required. t which use the standard but have different levels, ncies can be made compatthrough the use of concertain types of multiuse nonstandard frey allocation plans and therefore cannot be ed at the group or supergroup level even with . . Appearances for such equipment may be wideband jackfields for monitoring and testing only. (2) DCS standard levels and impedances for group, supergroup, and baseband have been established. However, them are still types of multiplex equipment in use which have been designed to operate at other levels and impedances. In stations where multiplex not conforming to DCS standard levels and impedances exists or is programmed for installation, a local standard is established. The term standard when used in this manual refers to that standard which is in use, either the DCS standard of local standard of levels and impedances. (3) A stand&-level jackfield is provided. It includes appearances of groups, supergroups, and base bands of all multiplex equipment operating at the standard levels and impedance, group and supergroup connectors designed to operate at those levels and impedances, and one end of each conditioning string. c. Conditioning Chains or Strings. Conditioning equipment chains or strings are usually made up of the following types of components. Not all components are required for every string. Only those components necessary to match the levels, impedances, and pilot frequencies of a particular type of nonstandard multiplex to the station standard is included in each string. (1) Impedance matching equipment is required to 2-25 TM 11-5895-1012-10 match a variety of impedances encountered in different types of multiplex equipment, including 600, 150, and 135 ohms balanced and 75 ohms unbalanced. Not all of these will ordinarily be found in the same station. (2) Level adjusting equipment is used to coordinate the levels of groups, supergroups, and basebands of nonstandard multiplex with the standard levels. This equipment includes adjustable attenuators and wideband amplifiers. The impedance matching feature described above may be combined with the attenuators or amplifiers or both in integrated assemblies. (3) Group pilot frequency conversion equipment is used to change nonstandard group pilot frequencies to the standard frequency without change in level. This equipment removes the incoming group pilot, converts it to the desired frequency, and reinserts it at the same level as the incoming pilot. The reinserted pilot level will track any variations in the incoming pilot level with an accuracy of ±0.5 dB. Pilot alarm equipment to indicate variation in pilot level beyond allowable limits is usually associated with the frequency conversion devices. 2-20. Internal Systems Systems internal to the Technical Facility include all of the nontraffic handling subsystems, which include but not necessarily limited to those described in the following paragraphs. b. Intercommunications (Intercom) System. The intercom system provides technical coordination internal to the Technical Control Facility and to support ing and using agencies located in the vicinity of the TCF Intercom service is provided through the use of existing administrative telephone circuits which contain the intercom feature, and through the application of a multistation intercom system. The intercom system shares common equipment and operator panels with the orderwire system. The number of intercom station locations varies with the operational mission and actual TCF configuration. The audio and dc patch bays are equipped with a sufficient number of intercom stations to allow access from each working location. As a minimum, one intercom station is pro vided for every three patch bays. c. Alarm System. An alarm system is provided to alert the Technical Controller and maintenance technicians of equipment degradations or failures that affect communications circuit status. Information pro sented by the alarm system initiates prompt action toward the restoration or rerouting of circuits and the repair of faulty equipment. Display of alarms is in a central location provided in the Technical Control Facility operating area. Parallel presentation of portions of the alarm display is also required in maintenance 2-26 and operating areas remote from the (supervisory. maintenance, or service areas). The amount and type of equipment necessary to satisfy this requirement is dependent on the TCF size and will vary from site to site. (1) All alarm outputs are accessible at the main frame. According to equipment types, alarms are designated as “go-no-go” or analog types (for adaptation t more sophisticated monitoring). The alarm display ix cludes but is not limited to the following as applicable to the station configuration: (a) All radio paths. (6) Cable carrier systems. (c) Data circuits. (d) Circuits having an alarm feature. (e) Common equipment units which could affect service. (f) Low transmitter output. (g) Low receiver input. (h) High received noise on the radio channel. (i) Failure of standby equipment. (j) Failure of primary equipment. (k) Signal level, high or low. (l) Power being used <primary, secondary emergency, auxiliary, or battery). (m) High or low power voltage. (n) Open fuse alarm. (o) High or low pilot frequency level. (p) Failure of line signalling supply. (q) Low fuel supply for generator. (r) Open door or window (at unattended station). (s) Failure of obstruction or warning light. (t) Change in waveguide pressurization. (u) Fire in equipment area. (v) Failure of environmental control system. (2) The alarm system provides for incremental es pansion. The system is usually so designed that activations, deactivations, and changes of transmission systems, TCF subsystems, and circuits can be accommodated without affecting the operation of the basic system. The system is usually broken down into two subsystems: (a) A local equipment and functions alarm subsystem. (b) A remote station equipment and function alarm subsystem. d. Orderwire System. An orderwire network is provided for efficient TCF procedures. Information regarding circuit and facility statu work, and maintenance and trouble co mitted over this network. Voice and da up the orderwire network and provid means of coordination between two or tween a TCF and associated PTF, and and some special communicati use TM 11-5895-1012-10 and type of orderwire circuits required at TCF's vary from site to site as dictated by station size, mission, and location. 2-21. Station a. Types. Different types of cabling are necessary for interconnection of the various equipment and keying lines with the Primary and Equal Patch Bays as well as the transmission media equipment and subscribers. (1) Voice frequency lines generally use appropriate sizes of shielded, single pair wires. (2) Direct current keying lines use individually shielded pairs. (3) Standard power cables are used to distribute primary power to equipment (4) Coax and twinax are used for high speed data MODEMS. b. Routing. Cables are usually installed in one or a combination of the following four methods; overhead inclosed ducts, overhead open racks, cellular flooring, and floor trenches. c. Shielding. Prevention of mutual interference between circuits that carry dc keying signals and circuits that carry vf signals is accomplished by shielding the dc keying circuits. Whenever feasible, separate racks or ducts should be used for each type of circuit. 2-22. Distribution Frames a. All in-station lines, equipment and channels, plus external cable pairs, terminate on a distribution frame. A main distribution frame is used for terminating outside lines and an intermediate distribution frame is used to terminate in-station lines. However, in the interest of simplification and conservation of apace it is common practice to use a combined distribution frame within the Technical Control Facility. The distribution frame is made up of vertical and horizontal terminating blocks. The vertical blocks, used for terminating outside lines, are provided with protective devices to shield the cables and associated equipment from high voltages surges. The horizontal blocks are used to terminate the in-station cabling. Cross connections are made on the distribution frame to obtain the desired circuitry. b. Jack appearances, in the Primary and Equal Level Patch Rays, are terminated on the combined distribution frame as are the equipment associated with collocated facilities. c. Temporary arrangements of circuits and equipment can be provided in the patch bays with the use of patch cords. However, all permanent changes should be made on the combined distribution frame in order to minimize the requirements for patch cords in use at any time in the Technical Control Facility. d. All cable runs and equipment connections are made to provide transmission security. The criteria are based on the concept of separation of red and black circuitry within the TCF and the DCS Station. In order to accomplish this separation, there are two separate distribution frames provided. One to carry the red circuits and the other to carry the black circuits. (1) Red Frame. The red frame is used to make crossconnections between red circuits, patch panels, and equipment, Red circuits are those circuits which carry or are cleared to carry, clear text, classified traffic. The red frame has a horizontal aide and a vertical side like any other combined distribution frame. Termination blocks are mounted on both tides of the red frame. The vertical side is used to terminate equipment, such as relay center equipment (send and receive); the clear side of the COMSEC devices (send and receive); the red side of battery isolation relays (send and receive); and for red circuit control, switching, or monitoring devices. The horizontal side is used to terminate the red patch panels and the positive and negative rectifiers used to furnish battery. If any traffic-carrying circuits which are approved for handling clear text classified traffic without COMSEC devices are in use, the lines will be connected to the vertical side of the red frame. The cables which are used to connect the items listed above to the red frame are permanently connected to the left side of the vertical blocks and to the bottom side of the horizontal blocks. Cross-connections are made as required to connect battery, equipment, patch panel jack appearances, and COMSEC devices together to form a circuit. (2) Black Frame. The black frame is used to make cross-connections between black circuits, patch panels, lines and equipment. Black circuits are those circuits which carry encrypted traffic or unclassified, clear text traffic. The black frame is the same configuration as the red frame, having a horizontal side and a verticd side. The horizontal side is used to terminate the audio and dc patch panels of the TCF and the positive and negative battery supplies. The vertical side is used to terminate the following items: all landlines, both audio and dc; the black or encrypted side of COMSEC devices; the black side of battery isolation relays; and any black circuit control, switching, or monitoring devices used in the TCF. The various items are cross-connected as required to form the desired circuitry. 2-23. Power Facilities a. General. Each Technical Controller must be aware of power facilities used to provide primary and auxiliary, and emergency lighting power at the DCS Station. A detailed discussion of power facilities and equipment is given in paragraphs 2-24 through 2-28. b. Primary Power. The term primary power is used at DCS Stations to denote the primary ac power source to the DCS Station under normal operating conditions. 2-27 TM 11-5895-1012-10 c. Auxiliary Power. Auxiliary power is provided at each DCS Station to replace all or part of the primary power in case of failure. This auxiliary power is usually supplied by engine-generators and storage batteries. These engine-generators are installed and operated as part of the DCS Station. Auxiliary power is the currently-approved designation for back-up or alternate power sources frequently referred to as emergency power sources. d. Emergency Lighting Power. Emergency power requirements at DCS Stations are normally limited to battery-powered lighting systems for use while auxiliary power equipment is being activated after failure of the primary power supply. These emergency systems are normally automatically activated immediately upon failure of the primary or auxiliary power supply, and are removed from service as soon as primary or auxiliary ac power is restored. 2-24. Classes of Power Station power is divided into four classes as follows: a. Class A Primary Power. A primary power plant which provides an essentially continuous supply of electrical power. b. Class B Auxiliary Power. A standby power plant to cover extended outages (usually days in length) of a primary power plant. c. Class C Auxiliary Power. A quick start (10 to 60 seconds) unit(s) to cover short-term outages (usually hours in length) of a primary power plant. d. Class D Auxiliary Power. An uninterruptible (no break) power unit(s) using stored energy to provide continuous power within specified voltage and frequency tolerances. 2-25. Types of Ac Power AC power is available in many different forms (voltage, phase, and frequency). The type required by a particular DCS Station is determined by the equipment installed at that DCS Station. a. Frequency. All ac powered communications equipment manufactured in the United States is available in models that require an input frequency of 60Hertz (Hz). Some equipment is also available in models that can operate on ac power supplied at different frequencies, such as 25 or 50 Hz. Most foreign-made equipment is designed to operate only from 50 Hz power sources. Since most of the equipment at any DCS Station will be manufactured in the United States, the primary ac power source should be 60 Hz. So that equipment designed for other frequencies can be operated, a rotary or solid-state static type converter is used to change the frequency of the primary power. b. Voltage. Most communications and test equip ment is designed to operate on 120 volts single phase. 2-28 However, equipment that requires large amounts of power, such as a high-powered radio transmitter, generally is designed to operate on 240 or 480 volt, three phase power. These are nominal voltages, and a variation of ±5 percent usually can be tolerated. (1) Some equipment is built with power input transformers, that have tapsbrought out to terminals. These taps are on the primary (input) side of the transformer, and are marked with a common voltage value. For example, a transformer in a piece of equipment may have-either three or five taps. If there are three tap, they usually are marked 105, 115, and 125 volts; if there are five taps, they are usually marked 105, 110, 115, 120, and 125 volts. Transformers for higher (2) Three-phase power requirements at DCS Stations are usually at a nominal 120/208 volt potential. However, some RF power amplifiers etc., may be designed to operate on different voltages, such as 240 or 416 volts. These voltages are supplied by special transformer configurations. c. Phase. Equipment that requires 120-volt input power is generally designed for single-phase power most equipment that requires 240-volt input power is designed for three-phase power. The generation of three-phase power is accomplished by three separate induction coils in the generator. The method of connecting these three coils results in various configurations, and may be arranged to give different voltages in the range of 208 to 480 volts. The threecoils, and the individual phases they produce, are separated by 120 degrees so that there is equality between the three phases. Higher powered generating plants normally produce three-phase power. The majority of the DCS Station equipment uses only single-phase power. Distribution of primary power within the station is important; therefore, disparity between loads on individual phases creates problems and should be balanced within reasonable limitations. 2-26. Generating Equipment a. General. The engine-generator sets provided at the DCS Stations are used for primary or auxiliary power requirements. For use as either a primary power source or an auxiliary power source, the electrical characteristics are the same. Normally, the only difference is that more sets of equipment are required if they are used to produce power at all times. For example, the general practice for auxiliary power is to provide two complete sets of power generating equipment. When they are used to provide all power for the station, at least three complete sets of equipment are required. b. Engines. The engine, or prime-mover is designed nave more horsepower than the generator rating; TM 11-5895-1012-10 this provides for losses and the capability to maintain constant speed at full load. The engine must also be equipped with a governor to maintain a constant output when the generator is connected to a varying load. Diesel and gasoline engines are used as prime movers. (1) Diesel Engines. Both low-speed and high-& diesel engines are used as prime movers. High-speed diesel engines can be installed at less cost than the lowspeed, heavy-duty diesel engine, but not operated or maintained as economically. (2) Gasoline Engines. Gasoline engines are used as prime movers to drive generators of limited capacity to supply power on an intermittent or purely auxiliary basis. They should not be used to drive generators to supply power continuously or over extended periods of time, because the useful life of a gasoline engine in continuous service is relatively short. The initial cost of a gasoline engine is much less than that of a diesel engine, but maintenance costs are higher. (3) Gas Turbines. Gas turbines have the advan- tages of light weight, quick starting, and acceptance of load without the usual warmup period. A disadvantage is their high fuel consumption rate. 2-27. Power Distribution a General. As previously indicated, most DCS Stations have at least two separate power sources, primary power and auxiliary power. These two power sources must be selectable; that is, switching and other necessary mechanisms must be provided to permit station personnel to select the desired source. Changeover must be fast, in fact, it should be possible to change power sources without any break in the power supply to the communications equipment. When primary power fails without warning, this may not be possible, but activation of the auxiliary power and connection to the communication should comply with the prescribed standards. In addition to the power changeover requirements, normal operation requires that the power demands within the station be balanced among the phases of *phase primary power supplies. b. Switchboards and Automatic Transfer Panels. EL3Z0055 Figure 2-10. Double bus arrangement and automatic transfer panel, wiring diagram. 2-29 TM 11-5895-1012-10 Automatic transfer panels provide an automatic switching arrangement designed to maintain power with minimum interruption for the operation of DCS Station equipment. Transfer panels must handle separate sources of power. In the case of a combination of generators, or of generators and commercial power (fig. 2-10). the desired power source can be selected to permit rotation of the engine-generators. A time-delay relay will postpone switching the load to any enginegenerator until the engine reaches its recommended operating temperature. If there is a gradual decrease in voltage, voltage-controlled relays will switch the load to an alternate source of power. c. Station Power Panels. The main power distribution panels are determined by the individual station requirements. When two or more power sources are operated in parallel, a master control switchboard pro vides a means for measuring the output frequency, voltage, and current. These measurements generally are made at the main bus bars, and thus indicate the total load and combined power supplied. d. Distribution for DCS Stations. DCS Stations receive power from an external distribution system or local Class A primary power plant. Distribution within the DCS Station begins at the main power panel and extends to the operating equipment. Subpanels, transformers, and circuit breakers may be included in the distribution circuits. Communication equipment in the station may he divided into two or more major groups. Each major group of equipment is connected to the main power panel. Radio transmitting stations have the largest and most complex power installation of the DCS. The output voltage and the configuration of engine-generators is connected to transformers, or direct& to the bus bars on the main switchboard. Distribution lines from the power panel to operating equipment are installed in floor trenches, in ducts, or on cable racks. e. Simplified Power Distribution. The following is a description of the simplified power distribution shown in figure FO-1. Many different arrangements are possible at all stages, and each station’s requirements will determine the best arrangement for the particular installation. (1) Primary power at 2400 volts is available from the commercial power source or from either of the two generators installed at the station. At the main switchboard, located in the utility building with the generators, power from any one or more of these sources can be applied to either or both of the power distribution cables to the operations building. In this example, all switching is performed at 240 volts, after reduction by deltadelta transformers. In some cases, these switching functions may be performed at the 2400-volt level and the transformer located in the operations building. 2-30 2-28. Uninterruptible Power Supply (UPS) (fig. 2-11, 2-12) TM 11-5895-1012-10 generator load and cranks the diesel engine with a minimum drop in frequency during the transition. After the diesel engine comes up to speed, it assumes the load and continues to produce power to meet the load requirements. During diesel operation, the commercial power is constantly monitored for voltage and frequency. When the commercial power returns to the correct voltage and frequency, normal operation is resumed, that is the commercial line contractor closes, the magnetic clutch is deenergized, and the diesel engine shuts down after a cooling-off running period. The electric motor and flywheel continue to operate. Figure 2-12 shows the unit in standby operation and figure 2-13 shows the unit online. b. Another method for providing uninterruptible power which is being utilized in overseas AUTODIN at the Automatic Digital Message Switching Centers (ADMSC’s) is shown in figure 2-13. This type of a UPS may also be found at DCS Stations other than those collocated with an ADMSC. Figure 2-11. Uninterruptible power supply in standby condition. Figure 2-12. Uninterruptible power supply in on-line condition. 2-31 TM 11-5895-1012-10 Figure 2-13. ADMSC uninterruptible power system. 2-32 TM 11-5895-1012-10 (3) The battery bank consists of 120 2-volt singlecell units connected in series. (4) There are four motor-generator units operating at any time, but a total of five units are available for operation. In case one of the operating units fails, the standby unit is automatically turned on, . synchronized, and switched on the line within 10 seconds. The UPS is designed so that, under normal operating conditions (four units on-line), each M/G set is operating at approximately 60 percent of rated load. Since the units are rated for a 25 percent overload last ing at least two hours, the UPS system is capable of operating with only two functioning M/G sets for brief periods, and with three sets for indefinite periods. This degree of redundance provides the critical portions of the ADMSC with great reliability. (5) Under normal operating conditions, four M/G sets are connected to the critical supply bus and are equally dividing the system load within their normal Based on these normal system operating conan automatic power load transfer is accomat the no-break critical supply bus as a result of one or more of the following abnormal operating system conditions: (a) Variation of generator output voltage belimits of plus or minus 10 percent of normal ue of 120/208 volts (sensed by the over and utput frequency be/2 Hz of the nomiand over frequency flow as sensed by (6) The following controls are built into the UPS to maintain the stabilized power required for the ADMSC: (a) Frequency Regulation. The magnetic amplifier type of speed regulator is provided with the dc motor of each motor-generator unit for controlling the M/G set speed, which in turn controls the output frequency. These speed regulators offer the advantages of high corrective output signal (high gain) from a relatively low level input with associated fact response to variations in the M/G set speed (frequency). The speed regulating system consists of a frequency detector, magnetic amplifier control circuit, and a single phase full-wave magnetic amplifier which controls excitation of the dc motor. (b) Voltage Regulation. The generator output voltage of each motor-generator unit is controlled by an individual magnetic amplifier type of voltage regulator. (c) Additional Controls. In addition to the above controls, each motor-generator set contains associated under and over voltage relays, and reverse current relays to monitor operation properly. Activation of any of these relays will energize the trip circuits of the input and output circuit breakers and remove the associated M/G set from the UPS system. c. Another method for providing uninterruptible power to critical loads is the solid-state static-type rectifier-charger-battery-inverter system shown by the simplified system block diagram in figure 2-14. This is a modularized redundant system each module consisting of a rectifier-charger unit, a battery (usually selected for 15-minute output), and an inverter unit together with appropriate protective devices. Each module has a 100 kilowatt (KW), 125 kilovolt-ampere (Kva) output rating. (1) The unit is designed for 200 kilowatt output. Normally the 200 kilowatt rated load is divided equally between the three 125 Kva units. In case of failure of any one unit, the unit that has malfunctioned is automatically removed from operation and the 200 K W load is divided equally between the two remaining units. Being modular constructed, the module that failed can be de-energized, the trouble located, and a new component inserted in the circuitry. (2) Since this type of UPS has limited operating experience, records of performance so far have indicated a mean-time-between-failure (MTBF) to be anticipated on the order of 80,000 hours. 2-29. Miscellaneous Power Equipment a. Storage Batteries. Storage batteries provide a compact source of dc power for the operation of equip ment requiring a dc source with a DCS Station. b. Dry Batteries. Dry batteries are used by DCS Stations to furnish power for certain alarm circuits, emer 2-33 TM 11-5895-1012-10 Figure 2-14. Solid state uninterruptible power system, simplified block diagram. gency signal lights, test equipment, etc. These batteries are available in various sizes and shapes and in several capacities and voltages to accommodate a wide range of uses. Special purposes dry batteries of higher than normal quality are also available for certain applications. c. Rectifiers. With an ac power source, rectifiers in conjunction with appropriate transformers and filters yield dc power with very little ripple content. Two common types of rectifiers are those that use electron tubes and those that use semi-conductors of the disk type (selenium, silicon, and germanium) as the rectifying medium. Some rectifiers are designed as part of a specific equipment and some of these cannot be used in other applications. However, many general purpose rectifiers are available. In efficiency, rectifier output is usually from 60 to 70 percent of the input power. d. Dynamotors. Dynamotors are rotating machines used to convert dc voltage of one value to dc voltage of another value and usually are components of specific equipment Usually, these units have only one set field coils and each set of armature windings is con nected to its own commutator. Essentially, dyna motors are motor-generators in which the motor and generator windings are wound in the same slot and on a single common armature. e. Frequency Changers. (1) Frequency changers are motor-generator sets that convert ac of one voltage and frequency to ac of another voltage and frequency. Frequency changers are used in DCS Stations to convert the incoming as frequency and voltage to match the input power re quirements of certain items of DCS equipment. (2) The motor-generator sets, depending on the application, may be driven by either a single or mull phase induction or synchronous type motor. The driving motor is usually coupled directly to the generator by a common shaft with both machines mounted on the same bedplate. Section IV. REPRESENTATIVE TCF EQUIPMENT 2-30. General introduction of high-speed data transmission into the DCS, the term “circuit conditioning” was little used in Technical Control Facilities. As higher speed data circuits came into wider usage, the term became increasingly familiar to technical controllers, especially as it applied to circuits obtained from have an understanding of the requirements for circuit conditioning and technical information on the equipment required fop circuit conditioning. This section 2-34 will discuss the conditioning equipment found in the TCF and those other items of equipment which are required to insure circuit performance and to enable the Technical Controllers to perform the function of the TCF. b. Ideally, all transmission systems and the channels of these systems should preserve the fidelity an amplitude of the original information. However, it is recognized that in a practical communications system the information carried over any transmission media is subject to certain electrical characteristic changes which result in loss, delay, or distortion of the transmitted information. Even though systems are properly TM 11-5895-1012-10 in electrical characteristics requiring conditioning equip distortion, envelope delay, signal level changes, and longitudinal balance. 2-31. Circuit Conditioning Equipment The following is a brief description of circuit condition equipment used on the DCS and found in the Technical Control Facility. a. Pads. Pads, which come in many forms and physical arrangements, are used to attenuate signals within a circuit. Pads found in telecommunications normally have the same input and output impedance; however, they can be designed to match impedance of different values. The attenuation introduced by a pad is variable, most usually by using different strapping options to adjust the amount of attenuation in steps of 0.5 dB. b. Amplifiers. An amplifier is used to increase signal strength without introducing appreciable distortion and to compensate for attenuation of signals on vf channels. Transistorized and vacuum tube amplifiers will be found in use on the DCS. Typical amplifiers used in circuit conditioning have an adjustable gain of from zero to 35 dB at 1000 Hz, stabilized within ±.2 dB and with a frequency response from 300 to 3400 Hz. Input and output impedances are usually 600 ohms balanced. c. Amplitude Equalizers. (1) Decreased intelligibility in voice circuits can be caused by the unequal attenuation of different frequencies. For example, as various frequencies pass along a nonloaded cable, the high frequencies are attenuated more than the lower ones. A l-mile section of 26-gauge high-capacity cable will have a loss of about 1.4 dB at 250 Hz; however, at 3000 Hz, the loss will be 4.5 dB, a difference of 3.1 dB per mile. Therefore, a 4mile section of 26-gauge nonloaded cable will result in a 5.6 dB loss at 250 Hz and an 18.0 dB loss at 3000 Hz. The 1000 Hz loss of the 4-mile loop would be 10.7 dB. The loss across the band, taken at these three frequencies referenced to the 1000 Hz loss, would be 5.1 dB less loss at 250 Hz and 7.3 db more loss at 3000 Hz. (2) The variation in loss across the band of interest can be compensated for by equalizing. The equalizing process consists of inserting into the circuit additional loss which varies with frequency. Sufficient is added at each frequency to bring the response across the band within a specified limit referenced to the loss at a specified frequency, usually 1 kHz. (3) The amplitude equalizer is any combination of coils, capacitors, or resistors inserted in transmission or amplifier circuits to compensate for differences in attenuation due to differing impedances at the various frequencies being used. Adjustments are usually provided to accomplish the required equalization. d. Envelope Delay Equalizers. (1) There is still another way in which voice-grade circuits can vary with frequency, and that is in the velocity of propagation. This variation does not usually affect speech transmission, but it can have an adverse affect on data transmission. (2) In any circuit there is a finite time interval for transmission from the sending end of the circuit to the receiving end. This time is referred to as absolute delay and varies according to the facility used. This time interval will also vary considerably between various frequencies in the transmitted band. This means that the shape of a signal wave at the receiving end can differ to an appreciable degree from that originally applied at the transmitting end. This distortion is called envelope distortion; and it is measured in microseconds of envelope delay. (3) Envelope delay distortion is the result of the deviation of the phase shift from a straight line pattern across the frequency band of interest. In carrier systems, the variation in time and frequency is caused mainly by the channel filters. Often additional distortion will be found in the outermost channels of a carrier group. This effect will be more noticeable in some systems than in others and is caused by the filter cutoff. Normally, it is good practice to avoid the lower and upper channels of a group or channels adjacent to pilot tones when channels are being assigned for data service. (4) Although delay distortion is found in cable and channel terminals, it should be remembered that equipment units, such as repeaters and coils, also contribute to delay distortion. These units affect the frequencies below 1000 Hz to a greater extent than those above 1000 Hz. In calculating the overall envelope delay of a circuit, the delay inherent in each equipment unit or line facility section, at specific frequencies, is summarized. When the delay of the equalizer is added to that of the equipment and facilities, the result should be within the limitations for the circuit being implemented. (5) For individual circuits which will be switched in tandem to form a completed connection, the delay requirements are much more stringent than for the overall connection. It is necessary, therefore, that each circuit, whether an interswitch circuit or access line, fall within the delay distortion limits established under the transmission plan for the system involved. This limit will be stated in the Circuit Layout Record (CLR) Card for the circuit. (6) There are two general types of equalizers used to compensate for the effects of envelope delay. One of 2-35 TM 11-5895-1012-10 these is often called “passive” equalization and the other "active” equalization. Passive equalization is generally used when referring to circuits where fixed equalizers are inserted after the required value is computed. Active equalization is commonly used throughout the DCS since such equalizers are continuously variable over wide ranges and may be simply adjusted by Technical Control Facility or maintenance personnel. (7) Either method of equalization ignores the absolute delay and only equalizes the relative delay. Delay equalizers consist of a series of networks with delay characteristics inverse to those of the circuit king equalized. Each adjustable section provides sufficient time delay in its frequency band to reduce the relative delay distortion. One unit in common use in the DCS reduces the relative delay distortion from 3 milliseconds to less than 80 microseconds from 1000 to 2000 Hz, to less than 260 microseconds from 200 to 1000 Hz, and to less than 500 microseconds from 500 to 600 Hz, and from 2600 to 2800 Hz. It is important that delay equalizers, particularly passive equalizers, be placed adjacent to a constant impedance attenuator or a 600 ohm pad to ensure proper impedance termination. e. Repeat Coils. A repeat coil is essentially a transformer which will transfer electrical energy from one source to another without metallic connection between the circuits. For direct current purposes, it divides the circuit into two portions. It was from this transfer function that the term “repeating coil” was originally derived, since it was used primarily to repeat information, rather than change voltage or current values as in power systems. Repeat coils are usually thought of as impedance matching devices, and the use of the proper ratio coil is a basic consideration in circuit design f. Echo Suppression (1) Echo. A problem, peculiar to long circuits that terminate in 2-wire instruments, arises from the velocity of propagation of the various facilities used for telephone communications. The time required for the transmission Of voice signals from one point to a distant termination will vary according to the type of facility and the overall length of the circuit. If, when a conversation is being carried on, some part of the speaker’s voice is returned to him from the distant termination, and the time involved is of sufficient duration, the returned voice signal will have the effect of an annoying echo. (2) Echo Tolerance. On circuits that are physically very short, currents return in such a short period of time that they take the form of sidetone, which is not objectionable to the talker. As the time interval increases, currents returned at the same level assume the form of an echo and become objectionable. Since 2-36 switched 2-wire PBX tion lines will not be since they do not have generate the echo. g. Telegraph tronic devices synchronous o them prior to retransmission. They are usually constructed to accept various modulation rates cept signals with up erative repeaters are for telegraph circuits, included as part of original circuit design and a continuing requirement for their use generally indicates circuit or equipment malfunctions which should be located and corrected and the regenerator removed from the circuit. h. Data Modems. This term is a contraction from the terms modulatordemodulator and all of these units, which are in use in the DCS in many forms and configurations, perform the same purpose. They convert digital signals to an analog form in the modulator portion and convert analog information into digital form in the demodulator portion. In certain special cases two modems are used on a back-to-back arrangement to provide regeneration for data circuits. In this arrangement the output of one modem will be put into another modem of the same type which will in turn provide a reshaped and retimed output. 2-32. Wideband Con a. Wideband condi egories, the first covering that condition required for the interconnection of voice frequency multiplex equipment with different characteristics; the second for the special conditioning required for 48 kHz channels utilized for wideband data or secure voice transmissions. The standard parameters for voice frequency multiplex, frequency division (FDM) which have been established for equipment used in the DCS are: (1) -34.5 dBr send level input. (2) -12 dBr receive level output. (3) 135 ohm impedance (balanced) for both input and output. (4) 104.08 kHz pilot. b. Any new vf FDM must operate at the TM 11-5895-1012-10 a considerable number of FDM terminals in use in the DCS which do not utilize the standard parameters. When interconnection at the group or supergroup level is required between this nonstandard equipment or standard to nonstandard equipment special conditioning equipment is required between the multiplexers for the purpose of level compatibility and impedance matching. This conditioning equipment is connected in the same manner circuit conditioning equipment would be connected on the circuit level. c. Nonstandard multiplex equipment in use in the DCS generally does not utilize the same pilot frequency as that used in the standard parameter (104.08 kHz). When multiplex utilizing different pilot frequencies must be interfaced at group or supergroup levels, pilot conversion is required. This process is referred to as pilot stop and reinjection. Suitable equip ment must be provided which will stop the unwanted pilot frequency and permit insertion of the required pilot frequency. Equipment which perform these functions are commonly called pilot stop and reinjection filters, and are especially designed for interface at the pilot frequencies of the multiplex terminals. 2-33. Other Conditioning Equipment Technical Control Facility personnel will be required to be familiar with the operational and technical characteristics of other ancillary equipment which may be required to assure proper operation but which are not usually referred to as conditioning equipment. a. Four to Two-Wire Terminating Sets. The four to two-wire terminating set is used between a two wire VF channel and a four-wire VF channel. It converts ‘the two wires used for transmit-receive to two wires for transmit and two wires for receive. Usually the terminating sets also provide impedance matching facilities, enabling 600-ohm 4-wire circuits to be connected to 600- or 900-ohm 2-wire circuits. b. 600-Ohm Terminations. The normal terminated impedance of lines used in telephone work is 600 ohms, although some 900 ohm terminations may be used. When the equipment normally used to provide proper termination is removed, the Technical Controller must have available a rapid method of terminating lines so that any test measurement made on the line will be accurate. A device in common use in Technical Control Facilities is a terminating resistor which is usually a noninductive resistor of the proper value wired across plugs of the same type as those used at the patch panels. c. Data Conferencing Network. This device (also known as a Technical Control Facility Hubbing Repester) enables a predetermined group of users to oper- ate such that if any one user transmits a message, it is received by all others in the group. The network allows any user to transmit as long as only one station is transmitting at any particular moment. The hubbing repeater may be used as the interface device between a Send Only device and several receiving terminals. d. Passive Peak Limiter. This unit is used to automat&By prevent system overload causes by excessive transmission levels from the user equipment This equipment is located on the equipment side of the Equal Level Batch Bay within the conditioning string on audio channels. e. 6-Way 4-Wire Bridge. This unit provides a conferencing capability for 6 each 4-wire telephone circuits. 2-34. Signaling Equipment The signaling equipment in the Technical Control Facility provides the means of interfacing ringing and dial pulse signaling between two different cross-connected channels. The equipment is also used to change the signal from out-of-band signaling to in-band signaling. Various types of signaling equipment is discussed below. a. Single Frequency Signaling Units (SFSU). This equipment is used when it is necessary to convert from E&M signaling to in-band 2600 Hz or 1600 Hz signaling or in-band to E&M signaling. The SFSU transmit section converts dc-dialing or supervisory signals present on the M-lead into an amplitude-modulated tone for transmission over voice frequency channels. The SFSU receive section converts received amplitude modulated tones into dc-dialing or supervisory signals on the E-lead. The state of the E&M leads may be grounded, +48 vdc, or open circuited. The normal E&M logic is as follows: b. E&M/Loop Converter (E&M to Dc). The dial loop to the E&M converter provides complete access be tween a central office and a dial user instrument over a voice frequency carrier channel. There are two versions of this unit as follows: (1) Central Office Dial Loop to E&M Converter. This unit receives 20 Hz from the central office and converts it to an M-lead seizure for input to an SFSU in the outgoing direction, and presents a closed loop to the central office when the E-lead from the SFSU indicates an incoming call. (2) User Dial Loop to E&M Converter. This unit recognizes a closed loop when the user goes off-hook and indicates seizure to the M-lead and converts dial pulses to M-lead pulsing of the SFSU. When a call is incoming to the user the E-lead causes a 20 Hz ringing signal to be sent to the end instrument. 2-37 TM 11-5895-1012-10 lead when a signal is received from the ringdown trunk circuit. It also receives signals over an E-lead from a signaling circuit and transmits 20 Hz signals to a ringdown trunk circuit. This equipment can be arranged to operate with signaling frequencies other than 20 Hz when required. d. E&M Signal-Lead Extension Circuits (DX1 and DX2). These signal-lead extensions units are designed to interconnect two signaling and supervision circuits when the metallic resistance between users exceeds operational limits. They are also used to interconnect an E&M signaling circuit to a distant trunk circuit which uses single frequency signaling. E&M signallead extension circuits are usually required where the connecting facility (cable) resistance exceeds 25 ohms (50 ohm loop). These circuits, which have been coded DX1 and DX2, are always used in pairs (a DX1 being connected to the trunk relay circuit and DX2 being connected to a single frequency signaling unit). They may be used in any combination, DX1 at one end of the circuit and DX2 at the other, or with like units at each end of the circuit. This equipment usually functions over metallic circuits with loop resistance up to 5000 ohms. e. Pulse Link Repeater. The pulse-link repeater circuit connects two signaling circuits, using E&M leads, by converting an incoming E-lead potential to an outgoing M-lead potential in both directions of transmission. This equipment does not connect to or affect the talking it is connected in the signaling path only. 2-35. Vf and E&M Panels A voice frequency jackfield is designed as an area in the Technical Control Facility where voice frequency circuits and their associated signal and control leads can be patched, monitored and tested. A patch panel is a signal unit in the jackfield. There are four types of voice frequency patch panels in the TCF; the Equal bevel., the 4-wire, the 6-wire primary, and the 2-wire primary patch panels. Each panel serves a different function as described in paragraph 2-17. a. Equal Level and 4-Wire Primary Patch Panels (fig. 2-15A) Each Equal Level and 4-wire primary patch panel contains 12 channels. Each channel occupies a paired jackset (a jack& consists of 4 jacks arranged vertically) of the panel as shown in figures 2-15 and F0-2. The receive circuit occupies the left jackset (odd numbered jacks) in each paired jackset, and the transmit circuit occupies the right jackset (even numbered jacks) of each paired jackset; therefore, the jacks are alternately labeled REC and TRANS. The top row of jacks are labeled LINE and are electrically toward the line or away from the Technical 2-38 patch panel has four cable connectors mounted on the rear of the panel. As shown in figure F0-2, C1 and C3 are used to bring the transmit and receive circuit leads into the panel. C2 and C4 are known as the normalthrough connectors. The normal-through wiring which connects the line side to the equipment side of the panel is routed through these connectors. Thus is provided to the normal-through connections for future uses, such as automation of the Technical Control Facility. b. 6-Wire Primary Voice Frequency Patch Panel (E&M Signaling). The 6-wire Primary Patch Panel is panel between them. The E&M patch panel provides signaling jack appearances for the 12 channels above, as well as the 12 channels below it. A front view of an E&M signaling patch panel is shown in figure 2-15B and the interconnection diagram in figure 2-16. The odd numbered jacks serve the E&M signaling leads of the vf above it while the even numbered jacks serve the E&M signaling leads of the vf panel below it. The top row of jacks is electrically toward the line, and the second row of jacks is toward the Technical Control Facility equipment. As with other patch panels, the normal&rough connections between the line and equipment sides of the panel (row 1 and row 2) are brought out to a normal&rough connector for future use. c. 2-Wire Primary Voice Frequency Patch Panel. This panel is similar to the 6-wire vf patch panel in that it has four rows of jacks for line side, equipment side, and monitoring operations. Since it is a 2-wire panel, it can hold 24 channels. Refer to figure 2-17 for the interconnection diagram of a 2-wire patch panel. 2-36. Dc Patch Panels a. Primary Dc Patch Panel. (1) Panel Description (fig. 2-15). The primary dc patch panel is that equipment within the Technical onithe TM 11-5895-1012-10 A. VF PATCH PANEL B. E & M (SIGNALING) PATCH PANEL Figure 2-15. Voice frequency primary or equal level and signaling patch panels. front view 2-39 TM 11-5895-1012-10 Figure 2-16. E&M patch panel, interconnection diagram. 2-40 TM 11-5895-1012-10 Figure 2-17. Two-Wire voice frequency primary patch panel, interconnection diagram 2-41 TM 11-5895-1012-10 Figure 2-17. Two-Wire voice frequency primary patch panel, interconnection diagram 2-41 TM 11-5895-1012-10 Figure 2-18. Dc patch panel, low level receive, interconnection diagram. 2-43 TM 11-5895-1012-10 Figure 2-19. Dc patch panel, low level transmit, interconnection diagram. 2 - 4 4 TM 11-5895-1012-10 radio communication links. The interconnection diagram of the receive panel is show in figure FO-4 and the interconnection diagram of the transmit panel is shown in figure FO-5. It can be seen that the wiring is similar to that previously discussed with the exception of the cut keys and lamps. (2) Receive Panel Cut Keys Functioning (fig. FO-4). When the cut key is operated to the down position, the indicator light is energized and the normalthrough circuit is broken and terminated. The receive circuit from the LINE side of the panel is terminated through a 5.6K ohm loop resistor to ground. The tip lead of the circuit toward the Technical Control Facility equipment is connected to hold battery. The corresponding ring lead is connected to an S lead and output via connector C1. This S lead provides a through path for any timing circuits which are present when the cut key is operated. Contact No. 5 energizes the lamp and output -48 vdc through the L lead to connector C2. The L lead provides the capability of energizing remote lamp to indicate that the circuit is cut. (3) Transmit Panel Cut Key Functioning (fig. FO-5). This cut key functions in a similar fashion as that discussed (2) above, except the loop resistor is placed in the cut circuit on the EQUIP side of the patch panel and the hold battery is placed on the LINE Side. 2-37. Miscellaneous/Interbay Patch Panels and Trunking a Miscellaneous Patch Panels (fig. 2-21). Miscellaneous (MISC) patch panels are located in the patch and test bays to provide the flexibility required for test and monitoring operations. The jacks are wired and cross-connected as desired by TCF personnel. Figure 2-21 provides a typical functional arrangement for a miscellaneous panel with 10 lamps in a Technical Control Facility. Figure 2-27 provides the patch panel interconnection diagram and block terminations. The patch panel provides such desirable jack arrangements and functions as 600 ohm loads, parallel jacks, line reversing (tip-to-ring, ring-to-tip), and -48 vdc power. The -48 vdc power is supplied via jacks 1 of rows 1 and 2. These two jacks are engineered to avoid unsafe or undesired jacking of the -48 vdc by designing the jacks for use only with a special double pronged MISC DC patch cord. Jack 1, row 1 is an undersized jack which will accept only one prong of this patch cord. b. Interbay Patch Panels. Each patch and test bay contains in interbay (INT) patch panel. Interbay trunks are used to route circuits to other patch bays in the Technical Control Facility. The various types of interbay trunks in the TCF are described below. c. MISC/INT Patch Panels (fig. 2-22). These pads, located in dc patch and test bays, may be used to perform either an interbay patch panel function or a mis- cellaneous patch panel function as described in a and b above respectively. The jacks contain normal-through contacts for greater flexibility as shown in figure 2 - 2 2 . d. Interbay Trunking Systems. The Technical Control Facility-has a voice frequency trunking system and a dc trunking system. The systems are designed to allow sufficient trunking of circuits from one patch or test bay in the vf or dc area to any other bay in that area. The vf and dc interbay trunking systems are not interconnected and come together only at the intermittent test stations. (1) Voice Frequency Interbay Trunking System. The interbay trunking capability in the vf area is provided by interbay patch panels which are mounted in the bottom of every vf patch and test bay. The panel has two rows of 24 jacks per row for a total of 48 interbay trunk appearances per bay. The front view of the panel resembles that shown in figure 2-21, however the interconnection diagram is that shown in figure 2-23. Terminal blocks Cl and C2 of each panel are cabled to the vf cdf where the panels are cross-connected to form a series interbay trunking system. The cross-connecting is done in such a manner that the same jack in each panel is assigned to the same patch or test bay. As an example, Jack 2, Bow 2, of every panel provides a trunk to the same bay. This scheme is shown in figure 2-24A. TCF personnel can alter the pattern as desired to provide additional trunks between heavy traffic bays or between bays and test stations. This system provides, generally, only one trunk between any two voice frequency bays or test stations. However, the patch cord length usually allows the use of trunks on either side of the bay providing three trunks to any one bay by direct trunking. (2) DC Interbay Trunking System. Interbay trunking capability in the dc area is provided by interbay patch panels with 48 lamps mounted in the dc patch and test bays. The panel has two rows of 24 jacks and two rows of 24 in-use lamps, as shown in figure 2-25. The panel interconnection diagram is shown in figure 2-26. The lamps are necessary since these cross panels are interconnected at the dc cdf into a parallel configuration (fig. 2-24B). Every pin on the block of one interbay panel with 48 lamps IS jumpered to the corresponding pin on the blocks of every second panel (odd panels form a parallel configuration and even panels form another parallel configuration). Each parallel configuration has 48 trunks for a total of 96 trunks in the dc area. The configurations are referred to as parallel since an interbay trunk appears on the same jack of every second INT panel appearance. As an example, Jack 1, Row 1 of one panel is in parallel with Jack 1, Row 1 of the INT panel two bays away and so on until all odd numbered and all even numbered bays are interconnected to form the two separate configura 2-45 TM 11-5895-1012-10 Figure 2-20. Dc Patch Panel (transmit or receive) with cut keys and lamps, front view. 2 - 4 6 TM 11-5895-1012-10 Figure 2-21. Typical miscellaneous patch panel, front view. 2-47 TM 11-5895-1012-10 Figure 2-22. Miscellaneous/Interbay Miscellaneous patch interconnection diagram. 2 - 4 8 TM 11-5895-1012-10 Figure 2-23. Voice frequency interbay patch panel, interconnection diagram. 2-49 TM 11-5895-1012-10 Figure 2-24. Typical series and panel interbay trunking systems. tions. When a trunk is put into use at one bay, the corresponding in-use lamp will illuminate at all the interbay panels where the trunk appears to indicate the trunk is in use. 2-38. Voice Frequency and DC Test Equipment A major responsibility of Technical Control Facility personnel is that of monitoring and testing circuits through the TCF to determine circuit quality and to determine operating conditions. Additionally, they are responsible for the rapid identification and isolation of faulty equipment in order to achieve optimum operating effectiveness. Accordingly, assorted test and monitor equipment is located through the voice frequency 2-50 and dc Technical Control Facility areas to provide an efficient means for performing these operations. It is not possible in a general type technical manual, such as this, to list every specific piece of test equipment to nomenclature of manufacturers name that could be found on every TCF in the world. However, instead a listing by genre is provided. This listing will help you identify the specific items installed at any TCF and briefly describe its function. a. Speaker Panels. Speaker panels are usually mounted in the bottom of the voice frequency test bays. These panels are used for aural monitoring of vf circuits carrying voice signals for the purpose of determining continuity and/or the quality of the speech traffic. The panel usually includes two amplifier TM 11-5895-1012-10 Figure 2-25. Dc interbay patch panel with 48 lamps, front view. 2-51 TM 11-5895-1012-10 Figure 2-26. Dc interbay patch panel with 48 lamps, interconnection diagram. speaker combinations. This allows two independent inputs and outputs. Both inputs are usually wired to jacks in the miscellaneous patch panel of that particular test bay. For monitoring purposes, either of these two inputs may be patched via interbay trunks to the monitor (MON) jacks in the voice frequency patch panel without degradation or interruption of circuit operation. b. Teat Bay Alarm Panels. Alarm panels are usually mounted at the top of each voice frequency and dc circuit test bay in the Technical Control Facility. The panel contains one or more rows of lights for the purpose of giving remote alarm indicates for selected equipment alarm circuits. The alarms circuit to be remoted are usually determined by the Technical Control Facility personnel. c. Noise Generator. The noise generator gives a flat response output signal over a wide range of the audio 2-52 spectrum. The output provides a signal to a circuit under test for measure at the other end with a noise measuring test set. d. Dual Channel Dc Amplifier Recorder. The dual channel dc amplifier recorder is used for simultaneous reading of two related variables then the variables need to be analyzed with respect to each other in time, or when up to two variables need to be permanently recorded. e. Transmission Measuring Test Set. The transmission measuring test set is used to measure transmission line and system characteristics such as attenuation, frequency response, or gain. It contains a wide range oscillator, a voltmeter, and a patch panel to match both the oscillator and the voltmeter to the various impedances found on the DCS (usually 135, 600 and 900 ohms). f. Noise Measuring Test Set. The noise measuring TM 11-5895-1012-10 Figure 2-27. Miscellaneous patch panel with 10 lamps, interconnection diagram. 2-53 TM 11-5895-1012-10 test set is used to measure signal levels, noise level and volume units (VU). The test set usually has a number filters for the inputs. Balance Test Set. The terminal balance test set when provided* allows for connecting and switching instruments required for each test without changing patch cords to the circuits to be tested. h. Wave Analyzer Test Set. The wave analyzer test set provides amplitude and frequency information over a given band of frequencies. The test set can separate frequency components of an input signal by means of selectable bandwidths and tuning controls. i. Patter Generator. The pattern generator is used to generate a wide variety of telegraph teat signal patterns having predetermined and controllable characteristics and parameters. The unit is used in conjunction with data measuring equipment to test and evaluate the performance of data/TTY systems or equip ment. j. Singing Point Test Set. The singing point test set measures the singing margin of 4-wire transmission circuits using hybrid terminations by inserting a variable, but known, gain into the circuit until oscillation occurs. The test set may also be used as a variable gain amplifier with a maximum undistorted output of usually 0 dBm at 600 ohms. k. Impulse Noise Counter. The impulse noise counter counts the number of impulses exceeding a number of different selected levels for a selected length of time. The unit provides a readout for each selected level, each giving the number of times an impulse exceeds the associated adjusted level. l. Phase Jitter Measuring Set. The phase jitter measuring set measures the peak to peak phase jitter indegrees. m. Transmission Delay transmission delay measuring test transmitter and a receiver which is used to measure signal delay and amplitude versus frequency. n. Data Analysis. Data analysis test sets provide the capability for comprehensive analysis and generation data, start, stop data, and nitor teleprinters are used to monitor teleprinter traffic in dc telegraph loops. A transmitting keyboard is usually included which, in conjunction with one of the page printers and utilizing a spare dc circuit, may be used in communicating between Technical Control Facilities for 2-54 the coordination of test fault isolation, or operational activities. Inputs to the monitor page printers are usually in the neutral mode. The output of the transmitting keyboard consists of dry contacts. The loop into which this output is inserted requires the application of operating battery from an external source. The printers and keyboards may be used in circuit operating at 60, 75, or 100 words per minute when appropriate speed change gears are used. A monitor teleprinter converter panel is usually provided which will allow the monitor teleprinter to be used without interupting the circuit being tested. The converter permits the insertion of the page printer into dc monitor jacks by converting low level voltage variations into current impulses needed to drive the page printer. p. Dual Meter Panels. The meter panel usually contains a high impedance voltmeter and low impedance milliammeter. The milliammeter is used to measure the telegraph loop current (high level). Loop current is measured by patching the meter input into a LINE MON or EQUIP MON jack at the equal level dc patch bays. q. Low Led Meters. These meters, mounted over various dc patch bays, provide a low level voltage reading when patched into the monitor jack of a dc circuit via the miscellaneous patch panel. The meters usually have a zero center scale, with ± 15 vdc full deflection. r. Reference Tone Generator. The reference generator provides 0, - 10, -8.7, and - 12.7 dBm tone levels (or others depending upon the man turer) to the patch and test bays. These test tone levels make jack appearances on the miscellaneous patch panels and then distributed to each patch and test bay. 2-39. Digital Line Interface Unit (DLIU) The digital line interface unit is a solid state plug-in printed circuit module for use as a line isolator and level converter generally located between the primary dc and equal level dc patch bays. It accepts a high level, neutral or polar, or low level signal and converts it to low level, polar and vice versa. The unit usually te with either synchronous or start-stop data up to 2400 baud. Automatic adjustable loop current regulation for high level output lines is provided as well as no transition/open loop detection and alarm, build-in loop battery fusing, and output monitor jack and self contained power supply for inter-circuit operation. TM 11-5895-1012-10 CHAPTER 3 EXAMPLES OF OPERATIONAL TCF'S Section I. PIRMASENS 3-1. Function a The Pirmasens TCF is a fixed station technical control facility containing equipment that provides termination, interconnection, patching, interfacing, conditioning, monitoring, and testing of voice frequency (vf) and direct current (dc) communications circuits and signals. b. The TCF performs the DCS Technical Control mission for the supervision and control of the transmission media at the Pirmasens Radio Station. This site is a radio nodal point (fig. FO-6) in the European Wideband Communication system (EWCS) serving microwave links to Langerkopf (LKF), Zweibrucken (ZBN), and Donnersberg (DON). In addition, the site provides cable links to local vf and dc subscribers. 3-2. Technical Characteristics equipment are listed below. Detailed technical characteristics of the individual components that are included in the TCF are listed in the appropriate technical manual. a VF Patching Facilities. Equal Level Jack Appearances (Full duplex) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1800 ea 6/Wire Primary (cable) Jack Appearances . 96 ea 4/Wire Primary (Cable) Jack Appearances (Full duplex) . . . . . . . . . . . . . . . . . . . . . . . . . . 720 ea 2/Wire Primary (Cable) Jack Appearances (In Bays 1.16, 1.17, 1.18)‘. . . . . . . . . . . . . .720 ea Nominal Signal Level.. . . . . . . . . . . . . . . .0 dbm Nominal Impedance . . . . . . . . . . . . . . . 600 ohms b. VF Conditioning and Interface Equipment. . . . . . . . . . ..<......... 1320 ea l . . . . . . . . . . . . 200 ea . . . . . . . . . . . . . . 40 ea 25 Hz Ringing Supply.. . . . .. . . . . . . . . . . .1 set Signal Supply Unit (2600 Hz) . . . . . . . . . . . . lea Signal Supply Unit (1600 Hz) . . . . c.. . . . .. lea Single Frequency Signaling-2600 Hz. . . . .75 ea Single Frequency Signaling Unit-16 Hz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82 ea d. DC Patching Facilities. DC (Equal Level) Jack Appearances (Full duplex). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 864 ea DC W/Cut Key (Equal Level) Jack Appearances (Full duplex) . . . . . . . . . . . . . . . . . . . . . .144 ea Dc Primary (Cable) Jack Appearances (Full duplex . . . . . . . . . . . . . . . . . . . . . . . . . . . . 480 ea e. DC Line Conditioning Equipment. Digital Line Interface Units (Full Duplex Shelf Space). . . . . . . . . . . . . . . . . . . . . . . . . .540 ea f. Orderwire Capability. Voice Orderwire Circuits.. . . . . . . . . . . . .20 ea Dc Orderwire Terminals . . . . . . . . . . . . . . . 24 ea AC Power Requirements. 208/120 VAC and 380/220 VAC at 50 Hz. A. DC Power Supplies. -48 VDC . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 ea -24 VDC . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 ea +130 VDC . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 ea -60 VDC . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 ea +60 VDC . . . . . . . . . . . . . . . . . . . . . . . . . . 2 ea ±6 VDC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 ea 3-3. Description of the TCF in a common building with multiplex voice frequency carrier telegraph (VFCT) equipment, and microwave equipment at the Pirmasens radio station, Germany. The TCF is housed in several rooms as shown in figure FO-8. The site is situated in three major areas; the dc and primary vf patch or test facility (Room 9), the vf equal level patch and test facilities (Room 12), and the line conditioning facilities (Room 8). a Description of Equipment w No. 1. Row 1 conties as well as the tains vf and dc patch and alarm and fuse bays for the 3-1 TM 11-5895-1012-10 tain dc patch panels (low level). Mounted above each dc patch panel is a Weston 273 low level voltmeter for monitoring purposes. Each patch bay contains an interbay panel with lamps and a MISC/INT patch panel. Bays 1.4 and 1.5 are dc test bays. Bay 1.4 contains an alarm panel, Digital Data Analysis AN/GGM-11, Express Link Order Wire Unit TA-923/FSC, and an AN/FGC-80 teletypewriter. Bay 1.5 also contains an alarm panel, an intercom unit, Digital Data Analysis AN/GGM-15, and a voice orderwire (O/W) unit. Bay 1.5 contains an interbay and a MISC/INT panel similar to the patch bays. (2) Primary VF Patch and Test Facilities. Bay 1.15 contains 6-wire primary vf patch panels; bays 1.16, 1.17, and 1.18 contain 2-wire primary vf patch panels. Bay 1.18 also contains four Hub Data Repeaters. At the bottom of each patch panel is an INT panel and MISC panel with 10 lamps. Bays 1.13 and 1.14 are test bays. Each test bay contains an alarm panel, and INT panel, and a MISC panel with 10 lamps. Test bay 1.14 contains a TTS-26BDR test set, a TTS-27 terminal balance switching set, and a TTS-56RP noise generator. Bay 1.13 also contains Express Link Order Wire Unit TA-923/FSC, a dc meter panel and Data ANALYSIS Central DAC-5. (3) Alarm, Circuit Breaker, Orderwire, and Blank Bays. Bays 1.19 and 1.20 contain orderwire equipment. Bay 1.21 contains the TCF’s alarm equipment. This consists of two major/minor alarm panels, two major alarm panels, and an alarm converter. Bay 1.22 contains dc circuit breaker panels. The top panel in the bay is the -24VDC breaker panel for supplying the alarm system. The bottom five panels supply -48 VDC power to the patch and test facilities. Bay 1.23 is blank for future expansion. b. Description of Equipment Row No. 2. Row no. 2 contains dc and primary vf patch and test facilities, as does row no. 1. Bays 2.1 through 218 contain AN/UGC-61X DC O/W terminals. Bays 2.9 through 2.15 contain dc patch and test facilities, while bays 2.16 through 2.23 contain primary vf patch and test facilities. (1) DC Patch and Test Facilities. Bays 2.9, 2.10, 2.13, 2.14, and 2.15 contain dc patch facilities (low level). Each patch bay has a low level voltmeter mounted above it and has an INT panel, a, MISC panel and a writing shelf mounted below the jackfields. Bays 2.14 and 2.15 are equipped with cut keys and lamps for use in conjunction with high frequency radio circuits. Bays 2.11 and 2.12 are dc test bays. Each test bay contains an alarm panel and a writing shelf. Bay 2.11 contains the voice O/W panel, an INT panel with lamps, and a MISC/INT panel. Bay 2.12 contains the intercom unit In addition the two test bays contain the following test equipment, Model PG-303A pattern generator, Teletype Carrier Test Set TCTS-2A, Digital Data 3-2 Analysis AN/GGM-15, and an AN/FGC-80 teletype writer set. (2) 4-Wire Primary VF Patch and Test Facilities. Bays 2.16 through 2.18 and 2.21 through 2.23 contain 4-wire primary vf patch facilities. Each patch bay contains an INT panel and a MISC panel with 10 lamps. Bays 2.19 and 2.20 are vf test bays. Each test bay contains an alarm panel, and INT panel, a MISC panel with 10 lamps, and a writing shelf. Bay 2.19 contains a voice O/W panel and a speaker panel. Mounted above bay 2.19 is a remote intercom speaker. Bay 2.20 contains a TA-923/FSC orderwire unit and a monitor speaker panel. In addition the two vf test bays contain the following teat equipments, TTS-12AR singing point test set, a TTS-37BR noise measuring set, a TTS-27R terminal balance switching set, an AN/USM-181B test set, and a TTS-56R noise generator. c. Description of Equipment Row No. 1A. Row 1A contains spare bays, HF radio control bays, and vf equal level (EL) patch and test facilities. (1) Radio Control Bays. Bays 1A.3 and 1A.4 each contain a test bay alarm panel. Bay 1A.3 contains two SCC recorder announcers and three AN/FTA-28 telephone terminals. Bay 1A.4 contains C-7667/FRR receiver control, a C7669/FRT transmitter control, a TA-923/FSC order wire unit and a TT-98/FG teletypewriter set. Bays 1A.5, 1A.6, and 1A.7 are used for HF radio control. The three bays contain Litcom Model 699A and Model 699B receiver and transmitter control units. (2) Equal Level VF Patch and Test Facilities. Bays 1A.8, 1A.9, 1A.12, 1A.13, and 1A.14 contain EL patch facilities. Below the jackfield in each patch bay is located an INT panel and a MISC panel with 10 lamps and a writing shelf. In addition, bay 1A.10 contains a voice O/W unit, a dual speaker panel. Mounted above bay 1A.10 is a remote intercom speaker. A TA-923/FSC order wire unit is mounted in bay 1A.11. The two vf test bays contain the following test equip ments, speaker panels, a TTS-37BR noise measuring set, an AN/USM-181B test set, a 1450-TBR attenuator panel, and a R561B oscilloscope with storage rack for extra modules. d. Description of Equipment Row No. 2A. Row 2A contains vf equal level patch bay and test bay has an INT panel and a MISC panel with 10 lamps mounted at the bottom of the bay. There are two sets of test bays in row 2A, test bays 2A.3, 2A.4 and test bays 2A.10, 2A.11. The left bay in each set of test bays (bays 2A.4 and 2A.11) contains a voice O/W panel and speaker panel. The right bays in each set (bays 2A.3 and 2A.10) contain an intercom unit and rack for stowing modules for the oscilloscope. Bay 2A.3 contains a TA-923/FSC order wire unit. All four test bays contain alarm panels and writing shelves. In addition, bays 2A.10 and TM 11-5895-1012-10 2A.11 contain a TTS-37BR noise additional monitor speaker panels, a oscilloscope and an AN/USM-181B test set. e. Description of the VF CDF Row No. 3. The VF CDF is constructed of open metal framework. One side of the frame, known as the horizontal side, contains 10 rows of 56 horizontally oriented terminal blocks. The other side of the frame, know as the vertical side, contains 10 rows of 56 blocks oriented vertically. In columns 22 through 26 of the vertical side, the terminal blocks are replaced by cable protectors for the purpose of terminating outside cable. f. Description of Equipment Row No. 4. Bay 4.1 through 4.15 and 4.19 are the voice frequency universal conditioning equipment bays. Each bay contains ten shelves with each shelf capable of containing 12 modules of vf line conditioning equipment. A fuse and alarm panel is mounted above the shelves with an intermediate distribution frame (IDF) located at the top of each bay for the purpose of easy cross-connecting. Bay 4.20 is known as the vf nonuniversal conditioning equipment bay. Mounted in the bay from top to bottom is a -48VDC containing equipment breaker panel, two shelves of Stelma 4-Way/4-Wire bridges, two Stelma SSU-1, signal supply units, a ballast lamp panel, a ring alarm and monitor panel, two 25 Hz ring generators, and six shelves of Northern Radio type 1030, model 2, 4-Way/4-Wire bridges. g. Description of Equipment Row No. 5. Row No. 5 contains all the dc condition equipment (DLIU's) necessary for the operation of the site. In addition, the 1000 Hz test tone generators are located in Row 5. (1) DLIU Bays. Bays 5.1 through 5.9 contain the digital line interface unit-s (DLIU). Each bay contains 10 shelves, each shelf capable of containing six DLIU's. A fuse/alarm panel is mounted above the shelves with an IDF at the top of each bay. (2) Tone Source Bays. Bays 5.19 and 5.20 contain the 1000 Hz tune sources for the TCF. A TTS-39A-4 tone generator is mounted at the top of each bay. Each bay also contains 14 TTS-39D-4 distribution amplifier panels. h. Description of DC CDF Row No. 6. The DC CDF is constructed of Open metal framework. The vertically oriented terminal blocks occupy a matrix of 10 rows of 48 blocks per row. In columns 41, 42, and 43, the blocks are replaced with cable protectors for the purpose of terminating outside cable. i. Description of Miscellaneous Equipment. (1) Supervisor's Console. Located at the head of all and test facility rows is the supervisor’s conin the console is a voice O/W panel and an unit. An Order Wire Intercommunications Section II. 3-4. Function TCF is a fixed station Technical Con- Termination Unit TA-930(V)/FSC is on the console. Behind the console is an AN/FGC-25XDC O/W terminal and test station no 1. (2) Intermediate Test Stations. The intermediate test station provides the capability of performing QA tests from locations remote to the patch and test facilities. Each test bay contains three interbay panels, one MISC function panel, an intercom speaker panel, and available rackspace for test equipment. Test station No. 2 contains a HP-302A wave analyzer. (3) Mobile Test Bays No. 1, 2, and 3 (not located). The TCF has three mobile test bays. The bays provide for the mounting of test equipment. Each test bay contains a MISC function panel and a writing shelf. Mobile test bay No. 1 contains a speaker panel, intercom unit, a Computer Measurements Company No. 800A, 802A, and 831B an AN/USM-181B test set, and an envelope delay distortion measuring set (ACTION LAB INC). Mobile test bay No. 2 contains a Tektronix R561B and extra module rack, an HP-320 dual channel dc amplifier recorder, and an ACTON 462A transmission delay measuring set. Mobile test bay No. 3 contains a speaker panel, a TTS-58AR impulse noise counter, an HP-312A frequency selective voltmeter, an HP-3550 transmission measuring set, and an envelope delay distortion measuring set TS-2669/GCM. (4) AC Power Panels. The ac power panels supply= ing the TCF are located at the head of rows no. 1 and 2. The fuse panels on the left supply 220 VAC power to ceiling lights, wall outlets, and ventilator exhaust fans. The TCF technical equipment is supplied by the two tech power panels which are fed via a 100A, 208/120 VAC fuse panel. The non-technical loads are supplied via the non-technical power panel which is fed via the 63A, 208/120 VAC fuse panel. (5) DC Distribution Bays 6.1 through 6.5. The dc power hays supply +130, ±60, -48, -24, and ±6VDC to the TCF. Bay 6.1 contains the control panel and two rectifiers used to supply +130VDC. Bay 6.2 contains the two PS alarm panels for the ±60VDC system. Below these panels are two +60 VDC and two - 60VDC power supplies, ± 60 VDC distribution fuse panels, a spare fuse panel, ±6VDC fuse panels and the ±6VDC power supplies. Located in bay 6.3 are two -24VDC Solar power supplies, a Lorain power board monitor panel (-24VDC) and a -24VDC fuse panel Located in bay 6.4 are two -48VDC power supplies, each with a -48VDC meter panel mounted above it. Bay 6.5 contains all the -48VDC distribution equipment which includes a ground bar, a -48VDC PS Lorain power board monitor fuse distribution panels. BERLIN trol Facility containing equipment that provides termination, inter-connection, patching, interfacing, condi 3-3 TM 11-5895-1012-10 tioning, monitoring, and testing of voice frequency and direct current communications circuits and signals. b. The TCF performs the Defense Communications System (DCS) Technical Control mission for the supervision and control of the transmission media at the Berlin Radio Station. This site is a radio nodal point ‘(fig. FO-8) in the European Wideband Communication System (EWCS) serving a microwave link to Tempelhof (TPF) and a French and British link. A tropospheric link to Bocksburg (BBG) and a satellite link to Landstuhl (LDL). In addition, the site providers cable links to local vf and dc subscribers. 3-5. The technical characteristics of the TCF and related equipment are listed below. Detailed technical characteristics of the individual components that are included in the TCF are listed in the appropriate technical manuals. a. VF Patching Facilities. Equal Level Jack Appearances (2 wire) . . .864 ea Primary Jack Appearances (2 wire) . . . . . . 960 ea Nominal Signal Leave (E.L. Patch Bays) . . 0 dbm Nominal Impedance.. . . . . . . . . . . . . . 600 ohms b. VF Conditioning and Interface Equipment. Echo Suppressor. . . . . . . . . . . ...:. . . . . . 36 ea Strappable Pads. . . . . . . . . . . . . . . . . . . . . .72 ea 4W Term Set . . . . . . . . . . . . . . . . . . . . . . . .31 ea Amplitude Equalizer . . . . . . . . . . . . . . . . . .56 ea Line Amplifier . . . . . . . . . . . . . . . . . . . . . .218 ea 4 Way - 4W Bridge . . . . . . . . . . . . . . . . . . . .2 ea 6 Way - 4W Bridge . . . . . . . . . . . . . . . . . . . . .2 ea Envelope Delay Equalizer . . . . . . . . . . . . . .12 ea C. Signal Conditioning Equipment Quantities. Test Tone Sources . . . . . . . . . . . . . . . . . . . .20 ea Ringdown Converter E&M to 25Hz/dc to 25 Hz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 ea Pulse Link Repeater. . . . . . . . . . . . . . . . ..100 ea 25 Hz Ringing Supply. . . . . . . . . . . . . . . . . . 1 set Signal Supply Unit (2600 Hz) . . . . . . . . . . . .2 ea Signal Supply Unit (1600 Hz) . . . . . . . . . . . .2 ea Single Freq. Signal Unit-2600 Hz . . . . . .108 ea Single Freq. Signaling Unit-1600 Hz. . . . . 10 ea d. Orderwire Capability. Voice Orderwire Units . . . . . . . . . . . . . . . . . .6 ea DTMF Access Units . . . . . . . . . . . . . . . . . . . .3 ea Dc Orderwire Terminals . . . . . . . . . . . . . . . .6 ea e. DC Patching Facilities. Dc Low Level Jack Appearances (Full Duplex) . . . . . . . . . . . . . . . . . . . . . . . . . .120 ea D C High Level Jack Appearances (Full Duplex) . . . . . . . . . . . . . . . . . . . . . . . . . . . 72 ea Dc Lane Conditioning Equipment. Digital Line Interface Unite (Full Duplex). .95 ea AC Power Requirements. 108/120 vac, three 3-4 phase, at 50 Hz. h. Dc Power Supplies. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 ea +120vdc . . . . . . . . . . . . . . . . . . . . . . . . . . . .2 ea ± 6 0 v d c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 ea ±6vdc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 ea 3-6. Description of the TCF (Fig. FO-9) a The TCF is housed in a building connected to the Berlin Tropo/Microwave Site. Four rooms are within the building, air conditioning plant room, office, maintenance room, and the technical control room. b. The technical control room has four bay areas. (1) Operation area, consisting of rows 1 and 2 along with the supervisor’s console and AN/UGC-54 teletypewriter. (2) Conditioning and interface area, which is row 3. (3) Combined Distribution Frame (CDF). (4) Voice frequency circuit telegraph and power bays in row 5. c. The technical control and maintenance rooms are illuminated by rows of ceiling mounted fluorescent lamps. Emergency lights (battery powered) are mounted on the right wall as you enter the building. The ac input power distribution panel along with the technical and non-technical power distribution panels are mounted on the opposite wall. d. The floor in the technical control and maintenance rooms raised and consists of a metal frame supporting tile covered wooden squares. All cabling and wiring between bays, CDF and ground box are below the raised floor. e. A description of the supervisor’s console is as follows: (1) The supervisor's console is located at the ends of equipment rows 1 and 2, and in front of the DCA, reporting orderwire teletypewriter. This allows easy access to all dc orderwire machines. (One at the end of each equipment row). (2) The console consists of two cabinets with a writing shelf between the cabinets. The left band cabinet contains storage drawers, ac power outlets at the bottom, and a power monitor panel at the top. The power monitor panel contains an ac voltmeter, frequency meter, and a dc voltmeter. Row 1 contains the following equipment: wire audio patch panels. Bay 1.02 has the No. 1 Universal Transmission Measuring System (UTMS) remote digital display unit at the top. Plus Signaling TM 11-5895-1012-10 Test Set TTS-26BDR is mounted in the bay below the display unit. Bay 1.02 also contains six 2-wire audio patch panels and a speaker panel. Bay 1.04 is the cable test bay, containing the No. 2 UTMS remote digital display, a HP-180 AR/TDR , a HP-4800 vector impedance meter, a speaker panel, and vf orderwire equipment. Bay 1.06 has the No. 3 UTMS remote digital display at the top. This bay also contains six 2wire audio patch pan&and a speaker panel. Bay 1.07 contains four 2-wire audio patch panels and a SB-1642 top resistance panel. The portion above the writing shelf of bay 1.08 is blank for future use as required. There is a SB-1642 loop resistance panel below the writing shelf. (2) High Level DC Patch Bays 1.09 and 1.10. Each of these bays contain a 48 lamp interbay panel, MISC panel, writing shelf, a loop resistance panel, and have ac power outlets at the bottom. Bay 1.09 also contains a dc meter panel and four dc patch panels. In addition Bay 1.10 contains a digital multimeter, two dc patch panels and Telegraph Test Set AN/GGM-15(V). (3) Fuse and Alarm Bay 1.11 and Orderwire Bay 1.12. Ray contains two major/minor alarm panels, a major alarm panel, three SB-1523/FT fuse panels, three loop resistance panels, and ac outlets at the bottom of the bay. Bay 1.12 is an AN/UGC-61X dc orderwire teletypewriter set. g. Row 2 contains the following equipment: (1) Equal Level Patch Bays 2.01 Through 2.06. Each equal level patch bay contains space for eight 2wire audio patch panels, INT panel, MISC panel, writing shelf, and a dual ac power outlet. Bays 2.02 and 2.06 have only six audio patch panels installed. Bay 2.04 is blank above and below the INT panel, MISC panel, and writing shelf. Bays 2.02 and 2.05 each have a remote digital display at the top of the bay and a dual speaker panel below the writing shelves. (2) Quality Assurance Bays 2.07, 2.08 and 2.09. These three bays each contain an INT panel, MISC panel, writing shelf, and dual ac power outlets. A baseband monitor panel and two echo suppressor control panels are mounted near the center of bay 2.07. The TTI-1140 Universal Transmission Measuring System (UTMS) master unit and power supply, along with the No. 7 remote digital display are mounted in bay 2.08. The UTMS associated relay panel, and a dual speaker panel are in the bottom of bay 2.09. The remaining space in the bays is provided for mounting test equipment. The test equipment may be rearranged or replaced as required by test requirements or change in the state of the art. (3) Low Level DC Patch Bays 2.10 and 2.11. Each patch bay has a low level voltmeter mounted above it and has a 48 lamp INT panel, a MISC panel and writing shelf mounted below the jackfields. Bay 2.10 contains five transmit patch panels and bay 2.11 contains five receive patch panels. (4) Low Level Test Bay 2.12 and DC Orderwire Bay 2.13. Test bay 2.12 is shown with a digital multimeter and AN/GGM-15(V) Telegraph Test Set installed. (These equipments may be changed as required). Below the test equipment area there is a 48 lamp INT panel, MISC panel, and a writing shelf. The low level ±6 volt power supplies, fuse panels and alarm panel are in the bay below the writing shelf. Bay 2.13 is an AN/UGC-61X dc orderwire teletypewriter set. h. Row 3 contains the following equipment: (1) Universal conditioning Equipment Bays. All the bays in row 3 except bay 3.04, 3.08 and 3.09 are universal conditioning equipment bays. Intermediate distribution frames (IDF) are mounted at the top of these bays. Below the IDF's are fuse-alarm panels. Each bay contains ten universal conditioning equip ment shelves, each shelf containing 12 module slots. Conditioning equipment modules are inserted into the shelves as required to build circuits through the technical control facility. (2) DLIU Bays. Bays 3.08 and 3.09 contain the digital line interface units (DLIU). Each bay contains 10 shelves, each shelf capable of containing six DLIU’s. A fuse/alarm panel is mounted above the shelves with an IDF at the top of each bay. (3) Non-Universal Bay 3.04. At the top of the bay there is a UTMS remote digital display, a MISC panel and a 4-way-4-wire bridge shelf. A 25 Hz ringing sup ply system consisting of ballast lamp panel, 20 Hz alarm and monitor panel, and two 25 Hz ring generators are mounted in the center of the bay. At the bottom of the bay there is a station reference tone source (TTS-39A) and four distribution amplifier panels (TTS-39D). i. The combined distribution frame (CDF) in row 4 is constructed of open metal framework. One side of the frame, known as the horizontal side, contains 30 rows of 10 horizontal terminal blocks. The other side of the frame, known as the vertical side, contains 31 columns of 9 vertical blocks per column. The first seven columns contain 750 four wire, line protector blocks. j. Row 5 contains the following equipment: (1) Mobile Test Buy 5.01. This bay is mounted on dolly type wheels to allow it to be moved throughout the TCF as required. The bay contains a INT/MISC panel, a storage drawer, and an ac power connector. The mobile bay provides rack space for the mounting of such test equipment as a digital multimeter, transmission measuring set, envelope delay test set and X-Y recorder. (2) Voice Frequency Carrier Telegraph Bays 5.02 Through 5.05. Each of the four voice frequency carrier telegraph (VFCT) bays is a Telegraph Terminal 3-5 TM 11-5895-1012-10 (3) Mux. Bay 5.06 and Power Equipment Bays 5.07 and 5.08. Bay 5.06 is a Collins MTX-201, VFCT. Bay 5.07 is the -48 vdc power source bay. There are two -48 power supplies at the bottom of the bay. Fuse distribution panels along with a Lorain power hoard monitor panel are above the power supplies. Bay 5.08 houses the ±60 vdc and 120 vdc power equipment along with a modified SB-1642 loop resistance panel. A Hub repeater is also mounted in the bay. Two dc voltmeter panels, three fuse panels and an alarm panel are at the top of the bay. Four Northern Radio Model 370-1 power supplies are below the Hub repeater. Two power supplies strapped for + and - 60 vdc outputs. (4) Orderwire Equipment Bay 5.09. The DualTone Multiple Frequency (DTMF) orderwire equip meat bay contains an SD-3751/FSC fuse panel, Remote Link orderwire Unit TA-924/FSC, one line card shelf, and two common equipment shelves. Duplex ac power outlets are in the front and rear bottom of the bay. IDF blocks, inductors, and a component board are in the rear of the bay. Section III. PENTAGON 3-7. Function a. Pentagon Telecommunications Center (fig. FO-10). The U.S. Army Communications Command Telecommunications Center (PTC) mmunications Systems (DCS) for b. Technical Control Facility (fig. FO-11). The cal Control Facility (TCF) at the Pentatechnical control over BED and BLACKITAL, and VIDEO circuits appearing at se are comprised of military-owned VFCT s and leased DC and data circuits. The high data circuits are in the 2400 to 50K BAUD The low speed circuits are predominantly secure circuits. Test and maintenance is also provided on Government-owned lines and circuits. c. Patch and Test Facility. (fig. FO-12). The P & T function includes the monitoring of circuits and equip. ment within a station, as well as the selection and application of the station facilities and associated equipment, as n to keep the station’s operating and standby communications links and circuits at peak . The Technical Controller coordinates in communications services at the station, alternate routings, directs the correction of functions, restores service when outages occur, and coordinates link and station tests. The P & T Facile station encompasses these areas which with jacks, and test instruments to provide access to the circuits for the purpose of performmonitor, patch and test operations. To efficiently perform the technical control func3-6 tions required to keep all communication links at their peak operating condition, all personnel must be thoroughly familiar with the station capabilities and the functions of all equipment in the station. In addition, familiarization with circuit links of related technical control is required. e. The Pentagon technical control facility is the main Army TCF serving the Washington D.C. area. The facility provides many high priority circuits to and from various local government users to locations scattered throughout the free world and to the Kremlin. Users and connecting sites often change. f. The patch and test facilities of the TCF provide access to each circuit for monitoring, rerouting, and testing. Access is provided to both the black (encrypted) and the red (clear) sides of the circuits. 3-8. Technical Characteristics a. VF Patching Facilities: Red VF Jack Appearances (2-wire). . . . . .264 ea Black VF Jack Appearances (2-wire) . . . .960 ea Nominal Test Tone Signal Leval . . . . . . -2 dbm Nominal Circuit Impedance . . . . . . . .600 ohms Normal Send Signal Leval . . . . . . . . . . . +8 dbm Normal Receive Signal Leval . . . . . . . . -13 dbm b. DC Patching Facilities: Red DC Jack Sets.. . . . . . . . . . . . . . . . . .912 ea Black DC Jack Sets . . . . . . . . . . . . . . . . 1,296 ea Nominal Signal Level . . . . . . . . . . . . . . . ±6 vdc C. Video Patching Facilities Red Video Jack Appearances.. . . . . . . . .160 ea Black Video Jack Appearances . . . . . . . . 100 ea Nominal Circuit Impedance . . . . . . . . .75 ohms d. AC Power Requirements . . . . . . . . . . . . . . . . . . . 208/120 vac, 3 phase, 60 HZ. e. DC Power Supplies 6 VDC . . . . . . . . . . . . . . . . . 4 ea: 2 Red, 2 Black 24 VDC. . . . . . . . . . . . . . . . . 4 ea: 2 Red, 2 Black 48 VDC . . . . . . . . . . . . . . . . 4 ea: 2 Red, 2 Black 3-9. Description of the TCF The equipment is housed in two different rooms. All of TM 11-5895-1012-10 the facilities (except the quality assurance (QA) equipment) are located in TCF, room 5A910 (fig. FO-12). There are three bays of QA equipment in the Electronic Maintenance Room (para 3-10). As shown in figure FO-12, the TCF consists of two rows of equipment bays, a red cable vault, and red and black ground and power distribution boxes. In addition the room contains Crypto equipment, modems, voice frequency carrier telegraph (VFCT) equipment and etc. Equipment rows No. 1 and No. 2 are described in paragraphs a and b below. Sample bay elevations are shown in figures 3-1, 3-2, and 3-3. a. Description of Equipment Row No. 1 (1) General. Equipment row No. 1 contains 21 bays of patch and test equipment and four bays of DCL/MOLINK equipment. Bays 1.22 through 1.24 (DCL/MOLINK) are covered in (C) PDEP 11-5895-832-14(2). Row No. 1 is called the black equipment row, because bays 1.1 through 1.21 connect to unsecure or encrypted circuits. (2) Black VF and Digital IDF Bays. Bay 1.1 con&b of two intermediate distribution frame (IDF) bays. Bay 1.10 consists of three IDF bays. Each bay contains a front door to allow access to a patch cord type cross connect matrix. The IDF's are similar and discussed in paragraph 3-11. (3) Black VF Patch Bays. Bays 1.2, 1.3, 1.4, 1.6 and 1.7 are the VF patch bays. Each of these bays contains eight 2-wire audio patch panels and an interbay (INT) patch panel. Bay 2.1 has a R-390 radio receiver in the bay below the patch panels. Bays 1.3 and 1.7 each have a 60 station voice order wire panel, that are furnished and maintained by the telephone company. Bays 1.4 and 1.6 have dual speaker panels and AM-911/FG audio frequency amplifiers mounted below the patch panels. (4) Black VF Test Bay 1.5. This bay contains various test equipment. There is a writing shelf with a miscellaneous (MISC) and INT panel above the shelf. In addition there are two test equipment connection panels. Test equipment without rear test lead connectors are connected to the MISC panel through the test equipment connection panels. (5) Video Monitor and Station Clock Bays 1.8 and 1.9. Bay 1.8 has two video monitors at the top, used to monitor the TCF door and outside hall. A panel with a push-button switch for unlocking the door is below the monitors. There are five TWINAX wide band patch panels in the bay. The remainder of the bay is used to mount test equipment. Bay 1.9 is a TDS-2 Station Clock Bay. (6) Black Digital Patch Bays. Bays 1.11, 1.12, 1.13, 1.15, 1.16, 1.17, 1.19, 1.20 and 1.21 are the black digital patch bays. Each bay has a ± 15 vdc meter mounted in the panel at the top. There are six universal dc patch panels and a INT panel with 48 lamps in each bay. The bottom of bay 1.11 mounts the black -48 vdc power system; consisting of two 48 vdc power supplies, an alarm panel, and a fused power distribution panel. Bays 1.12 and 1.19 each contain an order-wire panel. Bays 1.13 and 1.15 have writing shelves with AN/FGG-80 t&typewriter sets mounted on the shelves. One 24 vdc power supply is in bay 1.16 with a second unit in bay 1.17. Bay 1.16 contains the 24 vdc meter panel, alarm panel and fused power distribution panel. Bay 1.17 also contains the black 6 vdc power system; consisting of two power supplies (with alarms), meter panel, and fused power distribution panel. Bay 1.21 includes the black indicating equip ment; consisting of a MAJOR/MINOR alarm panel, audible alarm panel and two crypto ancillary unit/cornmon control unit (CAU/CCU) alarm panels. (7) Black Digital Test Bays. Bays 1.14 and 1.18 are the black digital test bays. The bays are similar in configuration. Each bay contains a ± 150 vdc meter panel, a 601 Data Transmission Test Set, HP-180BR Oscilloscope with connection panel, AN/GGM-15(V) Telegraph Test Set, INT panel with 48 lamps, and a writing shelf. b. Description of Equipment Row No. 2 (1) General. Equipment row No. 2 contains 20 bays of equipment and four bays of IDF patch cord cross connect matrixes. The four IDF bays are all numbered 2.21. Row No. 2 is called the red equipment row, because the circuits may carry secure information in clear test. Bays 2.1 through 2.20 are described in (2) through (6) below. (2) Special Intelligence Bay 2.1. SI bay 2.1 is isolated from the rest of the TCF. The bay contains a color video monitor at the top with eight video distribution amplifiers, and three 75 ohm patch panels. Between the monitor and amplifiers there are two universal dc patch panels (digital patch panels) and three 2-wire audio patch panels (VF patch panels). The bay also has its own IDF consisting of two rows of patch cord cross connect matrixes. (3) Red Digital Patch Bays (fig. 3-1). The red digital patch bays are bay 2.3 through 2.6, 2.8 through 2.11 and 2.13 through 2.16. Each of these bays has a ± 15 vdc meter mounted in a panel at the top of the bay. Below the meter panel there are six digital patch panels and a INT panel with 48 lamps. Bays 2.11, 2.13 and 2.14 each contain a writing shelf used to mount AN/FGC-80 teletypewriter sets. Each bay has blank panels below the patch panel. The blank panels may be removed to allow installation of equipment as required. (4) Red Digital Test Bays (fig. 3-2). Bays 2.2, 2.7 and 2.12 are the red digital test bays. Each of these test bays is used to mount test and monitor equipment. In addition there is an INT panel with 48 lamps and a writing shelf in each bay. 3-7 TM 11-5895-1012-10 (5) Red Power and Video Monitor Bays. Bay 2.17 mounts six dc power supplies (two 48 volt, two 24 volt and two 6 volt), along with associated fused distribution panels and alarm panels. The 6 vdc and 24 vdc supplies do not contain current and volt meters. There Figure 3-1. Red digital patch bay (typical), front view. 3-8 fore, a meter panel is provided to measure the output of these supplies. At the top of this bay there is a MAJOR/MINOR alarm panel along with an associated audible alarm panel. Video monitor bay 2.18 has a Figure 3-2. Red digital test bay (typical), front view. TM 11-5895-1012-10 3-10. Description of Quality Assurance Test Center (fig. 3-4) The QA test center consists of three bays located in the Electronic maintenance room. The bays contain test equipment and panels as shown in figure 3-4. The test center is connected to red circuits in the TCF through the RED REIAX 75 ohm INT TRUNK in bay 2. Black TCF circuits are connected to the QA test center through the black INT panel in bay 1.3. 3-11. Intermediate Distribution a. General. There are four IDF's in the TCF area They are an integral part of the Technical Control Facility and each equipment signaling input and output connections are terminated at an IDF. In addition, the input and output signals of each patch panel and circuit line are also terminated at an IDF. (Wide hand circuits are not connected through IDF's). b. Description. Each IDF consists of a matrix made up of rows of cross-connect panels. A panel contains ten jack type patch modules (A through H, and J, and K). Each module has six multi-colored rows of 26 jacks. The color of the jack rows at the front of the modules, from left to right are: red (A), white (B), blue (C), yellow (D), black (E), and orange (F). Each of the 156 jacks is connected to a pin on one of three associated connectors mounted on the rear of the panel. The first 48 jacks on the module are connected to pins 1 through 48 on connector J1. Module jacks 40 through 96 are connected to pine 1 through 48 on connector J2. Module jacks 97 through 144 are connected to pins 1 through 48 on connector J3. Module jacks 145 through 156 are also connected to connector J1, J2 and J3. Four jacks to each connector. The connectors are cabled to patch 3-12. Digital Circuits, General Figure 3-3. Red vf test bay (typical), front view. TCF provides cross-connection. monitoring, testing, circuit patching access, and timing clock for black and red digital circuits. A typical black circuit is discussed in paragraph 3-13. All digital circuits are connected through a Universal Digital Patch Panel. The patch panel and its different configurations are discussed in paragraphs 3-14 and 3-15. 3-9 TM 11-5895-1012-10 EL3Z0084 Figure 3-4. Quality assurance test center 3-10 TM 11-5895-1012-10 3-13. Typical Digital Circuit (fig. FO-13) a. General. In this example of a black digital circuit, the Universal Digital Patch Panel jack sets are programmed with a group 4 module in the send circuit and a group 5 module in the receive circuit. Refer to paragraph 3-156 and c for patch panel circuit details. This circuit is cross-connected in IDF bay 1.10. The local equipment (EQUIP side of circuit) is cabled to module A of panel 6. The line equipment (LINE side of circuit) is cabled to module A of panel 1. The jack sets of the Universal Digital Patch Panel are cabled to module A of panel 2. Optional devices are not used, but connections that could be used are shown. b. Send Circuit. To complete the send circuit, dualplug, cross-connect patch cords are installed as follows: (1) Patch cord No. 4, from jacks 1 and 2, module A, panel 6 to jacks 1 and 2, row 2, module A, panel 2. This connects the transmit data output of the user equipment to pin 5 of patch panel connector C-l. This is the jack sets tip (T1) lead, which is normal-through wired to pin 1 (tipT) of patch panel connector C-l. Pin 1 of C-1 is cabled to jack 1 of row 1 in module A, panel 2. The transmit data return is also cross-connected with patch cord No. 4, and is connected to a common tie point. (2) Patch cord No. 1, between jacks 1 and 2, row 1, module A, panel 2 and pins 1 and 2, row 1, module A, panel 1 completea the transmit data and transmit data return to the line equipment. (3) Patch cord No. 5, from jacks 3 and 4, row 1, module A, panel 6 to jacks 3 and 4, row 2, module A, panel 2 connects the transmit clock through the R1 and R leads of the patch panel jack set, to jacks 3 and 4. row 1. module A. panel 2 of the IDF. The transmit clock return is also connected to the common tie point through patch cord No. 5. (4) Patch cord No. 2, from jacks 3 and 4, row 1, module A, panel 2 to jacks 3 and 4, row 1, module A, panel 1 completes the transmit clock and transmit clock return to the line equipment. c. Receive Circuit. To complete the receive circuit, dual cross-connect patch cords are installed as follows: (1) Patch cord No. 7, from jacks 1 and 2, row 2, module A, panel 1 to jacks 1 and 2, row 3, module A, panel 2 connects the receive data line to the tip (T) lead set. The T lead is nor1 lead of the patch panrow 4, module A, panel rd connects the receive patch panel jack set to the receive pair of the user equipment. (3) Patch cord No. 8, from jacks 3 and 4, row 2, module A, panel 1 to jacks 3 and 4, row 3, module A, panel 2 connects the receive clock to the ring (R) lead of the patch panel jack set. The R lead is normalthrough wired to the R1 lead of the jack set and cabled to jack 3, row 4, module A, panel 2 of the IDF. The same patch cord also connects the receive clock return to a common tie point and to jack 4, row 4, module A, panel 2 of the IDF. (4) Patch curd No. 11, from jacks 3 and 4, row 4, module A, panel 2 to jacks 3 and 4, row 2, module A, panel 6 completes the receive clock circuit to the local equipment. d. Red Digital Circuit. A red digital circuit is connected in a similar manner and will not be discussed. 3 - 1 4 . Universal Digital a. Description. The front tains 24 sets of four jacks with a switch and lamp that is associated with each jack set. There are three rows of identification (ID) card holders. The card holders allow the circuit and equipment connected to the circuit to easily be identified. The rear of each patch panel has two connectors (Cl and C2), that are used to connect the jack set circuits (through connectors J1 and J2) to the IDF. Below the connectors are 24 program modules. Between the connectors and program boards there is a jack set ID strip indicating the jack set associated with each program board. b. Circuit Functions (fig. FO-15). Each jack set is connected (through a flexible printed circuit board) to a program board. The board is programmed by a program module (containing jumpers) to set up an operational circuit. The functions that may be performed by the circuits are given in (1) through (6) below. Two typical circuits for which modules are available are discussed in paragraph 3-15. (1) Provides a normal through path for digital signals when no patches are made. (2) When patching in a replacement sending device, the patching configuration will terminate the interrupted sending equipment in an impedance equal to the input impedance of the receiving device. (3) When patching in a replacement receiving device the patching configuration will hold the interrupt ed receiving equipment with a holding voltage or current equal to the mark voltage or current transmitted by the sending device. (4) The patch panel will perform the above functions for all the following types of digital signals: (a) Low level ± 6VDC send and receive. (b) Low level ± 3VDC send and receive. (c) High level polar or neutral send and receive. (d) Low level receive with associated timing. 3-11 TM 11-5895-1012-10 send with timing from an external standard to both sending and receiving devices. (5) The patch panel also incorporates a special circuits utilizing either an external function for timing standard or timing from a receiving device to a sending device. When a transmitted signal is to be receiving portion of the same patched back purposes, a problem would norequipment for mally arise. Since external timing is necessarily introduced on the line side of a jack field, a line-send-to-linel (back to back) patch required to perform ve test for equipment external to the TCF contwo timing signals (one injected into the send field and one received on the incoming line). Conversely, an equipment send-to-equipment-receive (back to back equip) patch required to perform the test for equipment internal to the TCF contains no timing signal. When timing is sent from a receiving device to a the same problem can occur (i.e., two on a back to hack line and none on a uip). A push button "back-to-back” switch allows the removal of one of the two timing signals present in a back to line patch and the introduction of timing in a to-back equip patch. An indicator light as well as switch position indicates the activation of this function in all cases. (6) The signal common “ring” lead of an interrupted signal is never left open. It may be supplied DC ground or another program elected termination. 3-15. Universal Digital Patch Panel, Programs 3-12 M3 to M2 D3 to E2 M3 to J3 H3 to E1 L1 to J1 F2 to F3 H3 to N3 (Not shown) Al to H1 (Not shown) A2 to M1 (Not shown E3 to K1 (Not shown) H3 to N3 (Not shown) C3 to D1 (Not shown) C3 to K3 (Not shown) (2) When a patch cord plug is inserted into the LINE jack, the following connections are made. Terminal T T1 R1 External timing (3) When a patch cord plug is inserted into the EQUIP jack, the following connections are made. Terminal T R External timing T1 To plugged line equipment R1 To plugged line equipment c. Black Receive Circuit, Program Module GP-5 (fig. FO-16). (1) This programming module connects the following terminals: B2 to E1 B1 to J3 C1 to F3 B3 to J1 C2 to N2 D2 to K3 TM 11-5895-1012-10 Termination To TCF equipment To TCF equipment Unterminated Unterminated Terminal T R T1 R1 Termination Unterminated Unterminated From pl line equipment From pl line equipment 3-13 TM 11-5895-1012-10 CHAPTER 4 TECHNICAL CONTROL FACILITIES OPERATIONS Section I. OPERATION PRACTICES AND METHODS 4-1. System Management sions. Examples of its specific station operational functions are: (1) In the case of the Berlin TCF, to provide a relay service to Templehof (TPF) and be the central access point to the Defense Communications System for subscribers in the local area. (2) In the case of Pirmasens, to provide wideband relay service to Zweibruken (ZBN), Langerkopf (LKF), and Donnersberg (DON) as well as being the central access point to the DCS. b. The mission of a TCF encompassed all of these actions necessary to maintain flexibility in traffic and circuit routing, reliability of through and terminating circuits, and peak efficiency in transmission quality. This capability can be realized only by employing approved management principles and by strict adherence to proven standard operating procedures at all stations. c. Overall system management direction resides with the Defense Communications Agency (DCA) and the Army Communications Command (ACC). Specific designed as the station control center and is equipped to permit effective station management. All operational orders, circuit activation and deactivation functions, system reporting, alternate routing procedures, formed by the Technical Control operators. Much of the content of this chapter is therefore addressed specifically to the station Technical Controllers and is intended to be used as a working guide in conjunction with station SOP's, records, and individual equipment manuals and handbooks. Since the circuit configuration is subject to operational changes a detailed study of the equipment description of those items on site should be made to ensure familiarity with the facilities provided. Moat of the day-to-day Technical Control operations require a thorough understanding of the complete station facility and the Technical Controller ing knowledge of the 4-3. Station Management Facilities and Usage 4-2. Station Management Approach. (1) High Frequency Interface. The multiplexed 4-1 TM 11-5895-1012-10 the TCF. Rerouting of the multiplexed groups is readily accomplished at this central point by patching. (2) Voice Frequency Channel Interface. The multiplex channel modems are wired to the Equal Level Patch bays in the VF Technical Control area. The patching facilities in this area provide access to the circuits. (3) DC Circuit Interface. In the TCF DC area, patching access is provided to DC subscriber loops and VFCT circuits by the DC patch facilities. b. Monitoring and Testing Functions. (1) Monitor and Test Point Interface. All VF and DC jacksets include a monitor jack appearance. These jacks are arranged to permit monitoring and testing without interrupting the circuit. (2) Teat Bay Interface. The test bays contain transmission measuring equipment and other test item to facilitate maintenance, fault isolation, analysis, and correction. c. Status Reporting and Coordination Functions. Operating personnel at the station are the primary users of the supervisory Subsystem which provides orderwire communications. This subsystem provides communications with other stations as required. Reporting requirements are established by the station SOP. 4-4. Duties 4-5. Orderwire Effective control of that comes under the responsi Facility requires format r a. General. The principal functions of the Technical controller are to moni d patch, as required, 4-6. Orderwire Procedures 4-2 TM 11-5895-1012-10 location. Technical control notices will contain a full heduled TELECON’s with the details arrangements with adecircuit, conduct tests and request is received without advance notice, the contacted TCF will provide the service as rapidly as possible. d. If the user reports trouble, immediate action will be taken to clear the trouble or provide an alternate circuit within normal restoration priorities. e. When notified by the user that the TELECON is finished, the controller will initiate action to break down the special arrangements used and return the circuit to normal use. 4-9. On-Call Patches 4-7. Orderwire Circuit Discipline 4-8. TELECON Circuits On-call patches is in no way intended to substitute for planning to meet known communications requirements. They will be activated for a period not to exceed 72 hours. If the requirement is to exceed 72 hours, the requesting activity will be advised to submit an emergency minor telecommunications requirement. When a request for an on-call patch is received the following action will be taken by the technical controller a. Determine and establish the route to be employed and the equipment required to provide satisfactory service. b. When the on-call patch cannot be established, contact the appropriate DOCC for assistance in accordance with established procedures. c. Report all on-call patches in accordance with established procedures. d. Construct a temporary CCSD in accordance with established procedures. e. Deactivate the on-call patch when notified by the user that it is no longer required. The technical controller will coordinate with the next TCF through which the circuit is patched to effect deactivation. All TFC's will follow the same procedure until the circuit is restored to normal. When the user will not release an on-cdl patch after 72 hours and an emergency telecommunication request has not been received, the appropriate DOCC will be notified for permission to break down the circuit. 4-10. Scheduled Service Interruptions Policy requires that the best possible communications service be provided to users of the DCS commensurate with available equipment and facilities. To provide this service it may be necessary, at times, to remove equipment from service or, in cases of major engineering changes, require the complete shutdown of a communications facility. These outages, which will be held 4-3 TM 11-5895-1012-10 to a minimum, are known in advance and every effort must be made to provide continuing service during the time a facility is out of service. When it is absolutely necessary to remove communications equipment, facilities, or an entire DCS Station from service, the planning, notification, and restoral of service must be thorough and complete. a. Planning. Service interruption will normally be scheduled when minimum communications impact will occur and will provide, where possible, for uninterrupted service to users. Planned actions will be time-phased to allow control to be maintained at all time, to ensure that communications capabilities will not be exceeded and to ensure the communications are successfully completed. Planning will include recovery should an emergency arise which would prevent the completion of planned actions. In addition, the planning will consider leasing of additional circuits from commercial carriers, as necessary, to provide uninterrupted service. b. Notification. It is of utmost importance that all users of the DCS be informed of any action that will or may tend to degrade their service. c. Supervision. Control and implementation of a scheduled service interruption rests with the TCF. Supervising DOCC elements will ensure that dependable communications are maintained to the element implementing the outage. d. No User Service Interruption. (1) When there will be no interruption of user service and sufficient spare or backup equipment is available during the affected period, no additional responsibilities, other than normal control practices, are required. (2) When there will be no interruption of user service and sufficient spare or backup equipment is not available during the affected period, the DCS station will notify the appropriate DOCC and operation and maintenance element of this hazardous condition. If necessary, the DOCC element may cancel or request rescheduling of this type of interruption. Further, it may be required that the users be notified of the existing hazardous condition. e. Interruption of User Service. For service inte ruption, other than a complete DCS Station, prior ordination and approval is not required on releases of single circuits or single channel concurrence has been obtained from terminals. However, if the interrup magnitude, but less than the comple nation and approval must be accomp tained in accordance with existing regula directives. Where the complete DCS Stat volved coordination and approval is ance with existing regulations and directives even though user concurrence has been obtained. 4-11. Emergency Interruption of Service prior coordination. However, as soon as possible, the circumstances involved will be reported to the various elements in accordance with existing regulations and directives. 4-12. Interruption of Service to Correct Hazardous Conditions cation is waived for complete station interruption of short duration to correct hazardous conditions providing all the following conditions are satisfied: a The station is in a hazardous condition and the condition has been reported in accordance with existing regulations and directives. b. All necessary equipment and the technical ex tise is available on-site to correct the hazardous co tion. c. User concurrence for the outage has been obtained. d. The interruption is scheduled for non-busy hours. e. Reroute or restoral actions will not be required f. Appropriate DOCC elements have been contac and advised that the above requirements have been met prior to the time of interruption occurs. Section II. CIRCUIT REROUTING 4-13. Introduction 4-14. Normal Circuit Rerouting Circuit rerouting is normally accomplished on a planned (scheduled) basis on orders from DCA or ACC. System planning and growth, circuit priorities, link or equipments reliability, subscriber population density, party line or command net configurations, and system maintenance may be major system operating factors which generate circuit rerouting requirements. In addition, system or equipment failures may necessitate emergency circuit rerouting. All normal circuit rerouting requirements are determined by ACC or higher authority and are primarily based on satisfying customer demands or improving communication services in a particular area of the systern. In the latter case ment is the result of operating and service taken from the daily technical control and maintenance logs and reports which are submitted by all 4-4 TM 11-5895-1012-10 ACC and/or higher headquarters. prior to getting the circuits back into service. Any nonpatching type rerouting actions required to restore service to less than highest priority critical circuits must be first coordinated with or have the approval of DCA or ACC. 4-16. Catastrophic Failure pleted, and the circuit verified in service, the station records are updated and details promptly forwarded to ACC in order that the system master files and records can be maintains current at all times. Circuit 4-15. Any circuit rerouting necessitated by system, equip ment, or facilities failure can be identified as an emergency requirement. Emergency circuit rerouting is accomplished in so far as possible, by temporary cord, plug and jack patching arrangement? at or through the Technical Control Facility using installed spare equip ments or channels to bypass the failed equipment or portion of the circuit or system. The magnitude of failure will determine the degree of emergency attached to each service interruption. A majority of the service troubles encountered can be attributed to failure of a minor item of in-station equipment; in this case, the station personnel are able to restore service expeditiously by patching in spare equipment or components. As soon as maintenance personnel repair or replace the failed items, the circuit is restored to its normal path. All troubles must be logged and reported, but the use of installed spares need not be coordinated with ACC The failure of link equipment, transmitters, or multichannel equipment involving critical highest priority circuits, either by error or intent of man, or by natural forces, are considered catastrophic failures. Under these conditions, the restoration of service to critical and high priority circuits is of paramount importance. Of equal importance at this time is the need to notify ACC of the failure event, the point of failure, extent of damage, estimate of work, equipment, and time involved in correcting the failure, and what has been done or is being done to restore service. Station supervisors and station Technical Controllers immediately take action to reroute predetermined critical and high priority circuits to the maximum degree possible over available spares whenever alternate routing links are available. As services are restored, DCA and ACC are notified. DCA or ACC evaluates initial reports and all subsequent status reports and initiates necessary instructions to Station Supervisors and Technical Controllers detailing additional circuits to be rerouted and routes to be used. DCA or ACC also indicates which, if any, lesser priority circuits will be preempted in order to maintain a maximum service balance throughout the entire system until the failures can be completely restored to normal service. Section III. PATCHING OPERATIONS 4-17. Pu of Patching Patching is defined as the rearrangement of the electrical interconnections among items of station equip ment by means of pat&cords and jackfields. a. Service Restoration. The various patching facilities provided in the station Technical Control area enable the Technical Controller to take positive action to restore service when a circuit failure has been localized to a station. Such restoration action consists of bypassing the defective equipment and substituting like equipment from the complement of operational spares and, similarly, substituting spare, or lower priority, channels for those degraded or inoperative. The substitution of equipment usually involves only a local patching operation, while substitution of channels requires a coordinated patching operation at the distant terminal. b. Fault Isolation by Substitution. Substitution of station equipment and channels by patching operaa valuable fault isolation technique. A logical re of successive substitutions of equipment and/or channels usually locates the trouble. Often, it is possible to patch out all station equipment in one patching operation, establishing quickly whether the fault is in any of the local station’s equipment. Once a channel or equipment has been patched out, test equip ment is employed to evaluate circuit performance and to localize the trouble. c. Service Continuity During Maintenance. Preventive maintenance routines require periodic quality control tests (Section VI) and adjustments of channels and station equipment. When it is necessary to conduct such tests on assigned channels or equipment,, service is maintained by a patching substitution. Fault isolation (Section IV) requires that the defective equip ment is disconnected from the circuit and a spare sub stituted. This substitution is accomplished by patching. d. Operational Spares. Operational spares facilities consist of spare multiplex and VFCT channels and selected items of equipment cross-connected into specific spare configurations. Whenever such spare 4-5 TM 11-5895-1012-10 equipment is available, spare circuits, which correspond to the DCS options in use at the station, may be established to permit rapid restoration of circuits by in-station patching. 4-18. Patching Precautions a. Temporary Measure. The use of patchcords to set up or rearrange circuits is intended as a strictly temporary measure. Service restoration patches should be taken down as soon as the fault condition has been cleared. In some cases, circuit orders may be issued which specify that patchcords be used to set up or rearrange a circuit to fill an emergency or temporary requirement. Such orders may specify, for instance, that circuits be established without delay by patching, and later by cross-connected at the frame to make a permanent configuration. The patch is to be taken down as soon as the normal circuit is arranged. The operational objective is to keep the jackfields as free of patchcords as possible. A multiplicity of patches in a jackfield frequently results in confusion as to the purpose and authority of the patches, and whether they are still required. To preclude such confusion, identification tags should be attached to any pat&cord setup which is to be left in place at the end of a Technical Controllers duty shift. The identification tag should contain the following minimum information: circuit number, terminal locations, using agency, mode of operation, authority, and time to be taken down. b. Patching Technique and Sequence. When patching operational circuits, it is essential that interruption, or service outage resulting from the actual patching procedure, be kept to an absolute minimum duration. In most patching operations, it is possible to limit the effect on a VP circuit to a momentary click, and on a TTY circuit to a few garbled characters. This minimum effect can be realized, however, only when the Technical Controller selects and follows the correct sequence in inserting the plugs in the jacks. The order in which this is done is important. Each of the many possible patching operations must be considered individually to determine the optimum order of events in the patching procedure. Experienced Technical Controllers always take a moment to think out the whole patching procedure before plugging into the jacksets. In general, the spare or alternate signal path should be set up first. The plugs should then be loosely set in the proper NORMAL-THROUGH jacksets, located in the signal path of the circuit to be transferred. Finally, in a coordinated procedure, the plugs should be simultaneously pushed all the way into the NORMAL THROUGH jacksets at two locations that constitute the end of the substitution path. 4-19. Reporting Patching Operations Patching operations which result in reconfiguration of 4-6 channels, rerouting of circuits, or cause interruption of service must generally be reported to higher headquarters. The specific reporting procedures to be followed are contained in the current station SOP. a Equipment Substitution. No operations reports are required for the substitution of equipment during routine maintenance operations. A Failure Report must be completed, however, if an equipment failure has occurred. b. HF Patching. Except as authorized in the current SOP, group patches may not be performed in the multiplex ares without prior coordination with, and approval of, the DCA and ACC. Notice must be furnished to the DCA and ACC following completion of the HF patching operation. c. Channel Substitution. The DCA sad ACC must be informed when a circuit is transferred to a spare channel, or to a channel of lower priority circuit. The notice should specify the time, circuit number, channel designator, reason, and expected duration of the rearrangement. This report is normally submitted after-the-fact, since the Technical Controller must take immediate action when patching is required to restore service. When it is necessary to preempt a lower priority circuit to obtain a substitution channel, the using agency must also be informed. When the circuit is restored, the using agency and higher headquarters must be notified. 4-20. Patching Operations Condu the VF Patching Facilities a. General. The jackfields associated with the VF patching facilities are used to gain access to signals in voice-frequency (300 to 3400 Hz) circuits for monitoring purposes, and to perform circuit rerouting, test measurements, level adjustments, and restoration of service by equipment substitution. Representative patching operations are given in b, c, and d below. The patch panels and jacks used are discussed in Chapter 2. The patching operations are shown in figures 4-1 through 4-3. NOTE The patching operations described below do not take into consideration the extension of E&M signalling leads through a patch panel. Where there is a signalling lead extension, use additional patch cords to transfer over all portions of the circuit. b. Transfer of a Circuit to a Spare Multiplex Channel (fig. 4-1). The situation requires, for test or maintenance purposes, that the user assigned to channel 5, be transferred to channel 2. This patch is made at the equal level patch panel (fig. 2-15) and the procedure is the same for Station A and Station B. (1) Place two patch cord plugs loosely into channel 2 REC LINE and TRANS LINE jacks. TM 11-5895-1012-10 (2) Place the plugs on the other end of the patch cords loosely into the channel 5 REC EQU and TRANS EQU jacks. (3) Establish voice contact between the Technical Controllers at Station A and Station B. (4) One Technical Controller will take charge and on a prearranged signal, usually the count-of-three, all loose plugs are set into the jacks simultaneously. (5) The transmit aide of the patched off channel (in this case channel 5) is terminated with a 600-ohm termination plug set into the TRANS LINE jack. c. Transfer of an Active (Circuit to a Spare Cable Pair (fig. 4-2). The situation requires that for test or maintenance purposes, the active circuit or channel 5 be transferred to the tail segment cable pair for spare channel 2. This patch is made at the primary patch panel (fig. 2-15) at Station A and the Patch and Test Facility patch panel at the other end of the cable. The patching operations are the same at both ends of the cable. Only the patching operation at the TCF is covered below. (1) Place two patch cord plugs loosely into the channel 2 REC LINE and TRANS LINE jacks. (2) Place the plugs on the other end of the patch cords loosely into the channel 1 REC EQU and TRANS EQU jacks respectively. (3) Establish voice contact between the TCF and the PTF. (4) The Technical Controller will take charge and on a prearranged signal, usually the count-of-three, all loose plugs are set into the jacks simultaneously. d. Substitution of Line Conditioning Equipment (fig. 4-3). The situation requires that for test or maintenance purposes, the spare line conditioning equip= ment (channel 2) be substituted for the active line conditioning equipment (channel 5). Before the patch is made, check the spare channel line conditioning equip ment to make sure it is configured the same as the active channel. The patching is accomplished at the primary and equal level patch panels (fig. 2-15) at Station A. Since the patch panels are normally physically separated, two Technical Controllers are needed to perform the operation with minimum interference to the users. The procedure described below is the same at both patch panels. (1) At the equal level patch panel, place two patch cord plugs loosely into channel 5 REC LINE and TRANS LINE jacks. Place the plugs on the other end of the patch cords loosely into the channel 2 REC EQU and TRANS EQU jacks respectively. (2) At the primary patch panel, place two patch cord plugs loosely into the channel 2 REC EQU and TRANS EQU jacks. Place the plugs on the other end of the patch cords loosely into the channel 5 REC LINE and TRANS LINE jacks respectively. (3) Establish voice contact between the two patch panels. On the count-of-three, all loose plugs are set into the jacks simultaneously. (4) On the equal level patch panel, terminate the channel TRANS LINE with a 600-ohm termination plug set into the TRANS LINE jack. 4-21. Patching Operations at Dc Patching Facilities a. General. The jackfields in the Dc patch bays are employed to gain access to Dc circuits for monitoring purposes and to perform circuit rerouting, test measurements and restoration of service by equipment substitution. Representative patching operations are given in b, c, and d below. A cut-key is provided to interrupt a telegraph channel for tactical considerations, or for the correction of an operational fault condition at either the subscriber station locations. In the event a condition exists which caused the teletypewriter equipment at the locations to run open, the Technical Controller activates the appropriate cutkeys to isolate the subscriber loops affected and applies hold battery to the subscriber teletypewriter machines. Upon correction of the condition, the cutkeys are restored to normal position. When a cut-key is activated, the following actions occur: the telegraph circuit is interrupted, hold battery is applied to the channel terminating unit and the associated cut lamp indicator is activated. This cut-key is also employed for scheduled interruptions of circuits such as those encountered with high frequency radio systems. b. Transfer of a Dc Circuit to a Spare VFCT Channel (fig. 4-4). The situation requires that for test or maintenance purposes, a teletypewriter circuit is to be transferred from VFCT channel 1 to a spare or lower priority channel 2. The patching operation is accomplished at the equal level dc patch panel at both the local and distant station. Coordination is required so that the patch is made simultaneously at both ends of the communications path to preclude loss of large blocks of record traffic. (1) Place two patch cord plugs loosely into the channel 2 REC LINE and TRANS LINE jacks. (2) Place the plugs on the other end of the patch cord loosely into channel 1 REC EQU and TRANS EQU jacks respectively. (3) Establish voice contact with the distant station. One Technical Controller will take charge and on a prearranged signal, usually the count-of-three, all loose plugs are set into the jacks simultaneously (at both ends of the circuit). c. Transfer of a Dc Circuit to a Spare Digital Line Interface Unit (DLIU) (fig. 4-5). The situation requires that for test or maintenance purposes, a teletypewriter circuit is to be transferred from the DLIU associated with channel 1, the normal channel, to the spare channel 2 DLIU. Before the transfer can be made the spare 4-7 TM 11-5895-1012-10 Figure 4-1. Transfer of circuit to spare multiplex channel at the equal level patch panel. 4 - 8 TM 11-5895-1012-10 Figure 4-2. Transfer of current to spare cable circuit at the primary patch panel. 4-9 TM 11-5895-1012-10 Figure 4-3. Substitution of line conditioning equipment using the equal level and primary patch panels. 4-10 TM 11-5895-1012-10 Figure 4-4. Transfer of a Dc circuit to a spare VFCT channel. 4-11 TM 11-5895-1012-10 patching is accomplished at both the equal level dc and primary dc patch panels. Since the patch panels are normally physically separated, two Technical Controllers are needed to perform the operation with minimum interference to the user. The procedure described below it the same at both patch panels. (1) At the primary dc patch panel, place two patch cord plugs loosely into channel 1 REC LINE and TRANS LINE jacks. Place the plugs on the other end of the patch cores loosely into channel 2 REC EQU and TRANS EQU jacks respectively. (2) At the equal level dc patch panel place the patch cord plugs loosely into the channel 1 REC LINE and TRANS LINE jacks. Place the plugs on the other end of the cords loosely into channel 2 REC EQU and TRANS EQU jacks respectively. (3) Establish voice contact between the two patch panels. On the count-of-three, all loose plugs are set into the jacks simultaneously. transferred to the tail segment cable pair for spare channel 2. This patch is made at the primary dc patch panel (fig. 2-15) and the Patch and Test Facility, or similar patching facility, at the other end of the cable. The patching operations are the same at both ends of the cable. Only the patching operation at the TCF is covered below. (1) Place two patch cord plugs loosely into the channel 2 REC LINE and TRANS LINE jacks (2) Place the plugs on the other end of the patch cords loosely into the channel 1 REC EQU and TRANS EQU jacks respectively. (3) Establish voice contact between the TCF and PTF. (4) The Technical Controller will take charge, and on a prearranged signal, usually the count-of-three, all loose plugs are set into the jacks simultaneously. Section IV. FAILURES AND FAULT ISOLATION 4-22. General a. All transmission media with breakout capability entering a DCS Station appears on the jack fields in the Technical Control Facility for control and restoral b. The Technical Controllers are responsible for all transmission media entering, terminating or transiting a DCS Station. (1) All traffic will be stopped where practicable before any action is taken that will interrupt its flow. When actions can be predicted; e.g. scheduled maintenance, the user will be notified in advance in order that traffic may be stopped at the scheduled time. (2) Occasionally, traffic will be interrupted due to unforeseen events, such as transmission media degradation or equipment failure, Traffic may also be interrupted by preemption of the circuit to restore a higher priority user. In all such cases, the user will be notified of the transmission media failure or preemption to permit them to stop traffic and maintain continuity. 4-23. Circuit Outages The Technical Controller is responsible for identification of all outages or interruptions on the circuit. Technical Controllers are also responsible for restoration of service with minimum loss of operating time. Controllers will test, monitor, and observe outgoing and incoming circuits and channels to ensure proper operation. They will coordinate with distant stations and local users, as necessary to isolate the report troubles. 4-12 All service interruptions must be logged, regardless of period of outage. 4-24. fault Isolation Fault isolation is the process of determining the location of a trouble within a circuit, or within the transmission media which carries the circuit The trouble could be in any of the transmitting facilities of one station, the receiving facilities of the adjacent station, the media connecting them, or the user's equipment which terminates the circuit. After the general area of a trouble has been isolated; e.g. media, user equipment, access lines, etc., a decision can be made to provide the quickest method of restoral. Fault isolation is not a finger-pointing or blame-fixing exercise. The basic purpose is to locate the source of a trouble and get it fixed, regardless of where it is, or which piece of equip ment is at fault. The same problem recurring at frequent intervals is of prime concern to both DCA and the operation and maintenance agency, and corrective measures must be taken. However, this is a byproduct, not the purpose of fault isolation. a. The first step in fault isolation is the recognition that a problem exists. On the surface, fault recognition may seem to be a trite statement. However, the majority of problems are the result of someone failing to recognize that trouble signs are appearing. Trouble recognition may be a result of quality control testing, equipment sensors and alarms, customer complaint, or any combination of these. The main point is that when the trouble signs appear, regardless of how or from TM 11-5895-1012-10 Figure 4-5 Transfer of a DC circuit to a spare digital line interface unit (DLIU). 4-13 TM 11-5895-1012-10 Figure 4-6. Transfer of a circuit to a spare cable pair. 4-14 TM 11-5895-1012-10 a system such as the DCS, there is little room for error. Even the smallest error can easily be compounded into a series of errors which can render a circuit, group, system, or service completely unuseable. Every station and link in the system was originally tested and accepted as meeting a specified level of performance. In order to continue operating at that level, each and every one of the electrical standards must be maintained with the established parameters. c. The DCS is made up of many different types of equipment which perform identical functions, but do not necessarily have the same electrical characteristics. For example, not all of the voice frequency channel multiplex equipments in the DCS are designed for a - 16 dBm test tone level input to the voice frequency modulator. Because of the detail differences which exist, there are no cut and dried, test-point by testpoint fault isolation procedures which cover all possible installations. There are certain functional areas which are the same in all systems, regardless of the installed equipment The procedures given in this section are addressed to functional areas rather than specific signal and test tone levels at the various equip ments. In addition to general fault isolation procedures, specific fault isolation procedures for the more common faults are also presented. 4-25. Responsibilities Responsiblity for maintaining the DCS at a high level of operation, rests not only with the DCS Stations and Technical Controllers, but also with the user, the DCA and ACC Operations Centers, and Maintenance personnel. a DCS Station. (1) Each DCS Station is responsible for the development of local fault isolation procedures based on the particular type of equipment installed in that station, the design capability of each link or system, patch panel and test point appearances, and test equipment availability. The procedures clearly delineate those functions which will be performed by technical controllers and those which will be accomplished by maintenance personnel. (2) Each station should have ready reference charts at or near each patch panel or test point showing the required teat tone level, the signal and noise levels, and the allowable tolerance at that test point, This data is gotten from the technical evaluation made at the time the equipment, link, or system was accept ed. (3) The requirement for maintaining the correct input or output signal levels cannot be over-emphasized. One or two voice channels operating with excessive signal levels can disrupt the entire baseband In fact, high levels inserted into one channel can disrupt other links or systems through which that signal is routed. By the same token, a change in signal level at one point will affect the level at all subsequent points in the system. Signal level adjustments must not be made without complete coordination with all locations that can be affected. equipment adjustments made by Technical Controllers will normally be limited to operational controls which are necessary for proper circuit or trunk operation; i.e., line current levels, composite audio levels, mode changes, channel reduction, or paralleling (twinning). They will not normally adjust, or attempt to adjust, any of the controls used for equipment alignment. (2) When a &graded condition or other trouble is encountered at a given station, the Technical Controller of that station coordinates with distant stations, local users, and associated transmitting and receiving elements in his efforts to isolate and locate the fault. He has primary responsibility for this action, and must receive full cooperation from all other station Technical Controllers involved. When it is determined that the fault is located at a distant station, or in a link serving an area beyond that station, responsibility for locating and correcting the fault is transferred to, and assumed by, the station Technical Controller primarily concerned. c. User. The user is responsible for notifying the responsible Technical Controller of all instances of service degradation evidenced by high data error rates, occasional noise bursts into the voice channels serving him, or other indications of unsatisfactory conditions. The user renders free cooperative to the Technical Controller and the correction of service degradation. d. DCA and ACC Operations Center. (1) The Operations Centers monitor the progress of the station Technical Controllers in their troubleshooting efforts, but under normal circumstances, does not actively engage in the isolation of a fault. If however, the station Technical Controllers encounter difficulties and cannot restore service within a reasonable period of time, the active Operations Center is responsible for assuming the overall direction of the corrective actions, for providing a workable solution to the problem, and for keeping circuit outage time to an absolute minimum. (2) Troubles encountered on multichannel or multilink circuits often are of an accumulative nature and present a complicated condition for resolution. To determine the cause, or causes of such a condition special link and segment tests may be required. The DCA and ACC are responsible for determining the requirements for such special tests on the basis of station re 4-15 TM 11-5895-1012-10 ports. The Operations Center coordinates the tests, collects and analyzes the results, and directs remedial actions as necessary. (3) Unless there are definite indications of a major abnormality the Operations Center normally does not take immediate action to inquire about circuit conditions, inasmuch as continuous inquiries by the Center impedes the troubleshooting and fault correction actions of the station Technical Controller and maintenance personnel. The Operational Center is responsible, however, for investigating outages which have not been cleared after a reasonable period of time, or if no explanation has been made by the remote stations or the cognizant master station, and for rendering assistance in restoring service. e. Maintenance Personnel. After faults have been located and identified, maintenance personnel are responsible for effecting necessary repairs and maintenance in accordance with appropriate technical manuals pertinent to the particular item of faulty equip ment. 4-26. F u n c t i o n a l A r e a s a. For purposes of fault isolation, a Technical Control Facility will fall into one of the following three functional areas: (1) A Technical Control Facility which provides the user with access to the Defense Communications System; i.e., the serving TCF. (2) A TCF which has voice frequency channel breakout, but does not provide the user a direct access to the DCS; i.e., a receive channel of one group is crossconnected to the send channel of another group.. (3) A TCF in which the signals appear at a group or supergroup level, i.e., no vf channel breakout. b. It is possible that a Technical Control Facility could be involved in more than one functional area at one time, depending upon the circumstances at that particular time and station configuration. 4-27. Troubleshooting Practices a. Fault Notification. Technical Controllers are alerted to actual, or impending circuit outages by means of alarm indicator displays, by notification from the user, of circuit deterioration or failure by a distant Technical Controller, and as the result of test ing and monitoring. (1) The supervisory alarm subsystems provide an alarm when a failure occurs in various equipment and systems at the DCS Station, such as single frequency signaling equipment, ringers, multiplex systems, fuse panels, or the dc power system. When alerted to an abnormal condition by an alarm, the Technical Controller and maintenance personnel must perform systematic step-by-step monitoring, or testing of the system segments into, through, and out of the station, in or 4-16 der to isolate the fault(s) to specific areas and/or equip- tivate the supervisory alarms, and consist noise bursts in the circuit data error rates, channel levels. Usually, these problems are brought to the attention of the Technical Controller by the user. The Technical Controller performs monitoring and testing routinely, as circumstances permit. However, when notified of degrading circuit conditions by the user, other Technical Controllers, or maintenance personnel, monitoring and testing of the degraded circuit in the Technical Control areas, provide a means of sequential access to circuits and groups between most of the major equipment in the station. b. Service Restoration. The Technical must use every means at his disposal to rupted service as expeditiously as possible. These means, when available, should be used in the following order of priority: (1) If a spare channel is available, the Technical Controller should patch the user circuit or group into a spare, while isolating and correcting the defective equipment. (2) If a fault is identified within an item of equip ment for which a standby or spare is available, the sub stitute equipment should be used to restore disrupted service while the defective equipment is being restored. (3) During prolonged, or projected extended outages, the Technical Controller should request alternate routing instructions. Rerouting or pre-empting is obtained from a list in the station SOP. (4) As a last resort, the Technical Controller should pre-empt lower priority circuits in order to restore service for high priority users. Every circuit, including switchboard trunks as well as allocated circuits, is assigned a priority of restoration which must be adhered to in channel restoration. Establishment of these priorities is performed on a worldwide basis by the Defense Communications Agency. C. Records and Reports. The Technical Controller who first determines that a fault exists or to whom a fault is reported by a user, is responsible for coordinating the fault-isolation activities with distant station Technical Controllers, and is responsible for appropriate log entries and reports. When a fault has been isolated, an explanation of the nature of the trouble must be entered in the reporting station log, and the distant Technical Controller must be notified so that the entries for both stations coincide. All circuit out TM 11-5895-1012-10 ages must be recorded on the appropriate station logs, of the duration of the outage time or the cause of the fault. Specific instructions for reporting of stations are contained in Standard Operating Procedures published by DCA and ACC. Trouble reports (work orders) must be prepared for each equipment or circuit failure. This work order will notify maintenance of the faulty or sub-standard equipment- Only by strict adherence to this procedure can proper records be maintained. Prompt, efficient repair of faulty equipment often depends upon the completeness and accuracy of these symptoms described on the written workorder. d. Catastrophic Failure. Normally, the Technical Controllers keep DCA and ACC informed of anticipated, imminent, or existing service failures or degraded conditions which are beyond the local capability to restore within a tolerable delay or outage time period. In an exceptional case, a catastrophic failure condition may be encountered in which the alarm indicator display may depict a number of simultaneous alarms or provide an indication of a second major alarm within the same station before the first alarm has been cleared. In these cases, DCA or ACC may provide alternate routing instructions, or other solutions, as applicable. 4-28. Fault Isolation Procedures The guidelines contained in paragraphs 4-29 through 4-34 are for use in preparing local procedures and in determining the location of the equipment or media which is causing signal degradation. It may not be necessary to take each step in the order listed. Depending upon the trouble indications, it is possible that some steps may be taken in different sequence, combined with other steps, or even eliminated completely. A Technical Controller’s first questions, when a problem is recognized, should be “Does the problem affect only a single circuit or channel, or the entire group or supergroup?” and then, “Is the circuit, group or supergroup meeting the standards through my station?” The Technical Controller must then take the actions necessary to answer those questions. All steps will be taken in complete coordination with the other stations through which the signal is routed, and with the local maintenance activity. a. Fault isolation should proceed from the point of fault recognition toward the signal source to the point where the fault exists. Results of in-station checks will be completely coordinated with the other concerned TCF's and the trouble corrected at the source. Adjust ments will not be made at intermediate points to compensate for a problem generated at some other point in the circuit or system. b. In the event a known fault cannot be corrected within a reasonable amount of time (i.e., 10 minutes), the Technical Controller should reroute or restore in accordance with established restoration priorities, pending completion of repairs. Difficulties encountered in obtaining a reroute path will be reported to the appropriate DOCC and reroute instructions will be requested. 4-29. Voice Frequency Fault Isolation When a Technical Controller discovers that a circuit or a multiplex group is not operating within established parameters, in-service monitoring tests should be performed in accordance with established station procedures. This will help determine whether a single channel, an entire group or supergroup, or the baseband is affected. In addition, whether the fault is located within the station multiplex or line conditioning equip ment. Time is important. The goal is to locate and correct the fault before the users service becomes unuseable. a. In coordination with the distant station(s) and the appropriate control office(s), using available orderwires, selective elimination of each portion of the circuit may be used to locate the fault area. In-station monitoring procedures will locate the fault specifically enough to permit the Technical Controller to modify established fault isolation procedures and attack the problem directly, either by substituting for the faulty item, or by making a patching substitution. Then through the use of out-of-service testing procedures, or the in-station test and alignment procdures, correct the problem. b. Keep in mind that the fault isolation procedures established, serve only as a guide for efficient technical control operations and do not represent a rigid sequence of steps which must be followed to solve a problem. The Technical Controller should by-pass any unnecessary steps in order to quickly locate the fault and restore normal service. 4-30. Single Voice Frequency Channel Fault When it is determined that a single voice channel of a voice frequency group is unuseable or deteriorated, the station Technical Controller will take the following action: a. Coordinate with the distant station Technical Controller to transfer service to a spare channel, or preempt a lower priority user if required. If a low priority user is preempted, have the distant station Technical Controller notify the low priority user of the preemption. b. Request the distant station Technical Controller to send a test signal on the faulty channel in accordance with the appropriate out-of-service test procedure after the traffic signal has been moved to another channel. 4-17 TM 11-5895-1012-10 4-31. Multichannel Fault following actions: a Determine whether alternate equipment is available for substitution. b. If none is available, notify the distant station Technical Controller to block the use of the faulty channels, and to send test signals on specific channels, preferrably on voice frequency channels 1, 6, and 12 of the affected group. c. Notify local users of circuit failure. d. Monitor the test signals transmitted by the distant Technical Control Facility. In conjunction with station maintenance personnel, coordinate maintenance necessary to restore the multiplex group or supergroup equipment to proper transmission standards by alignment, replacement, or repair. If the malfunction cannot be isolated or corrected within a reasonable length of time (i.e., 10 minutes), service will be restored in accordance with established procedures and assigned restoration priorities. e. When the malfunction has been isolated, corrected, and the circuits checked out, notify the distant Technical Control of the nature of the problem end request removal of test signals. If necessary perform additional out-of-service testing to ensure that all circuits meet specified parameters. f. Restore user service to normal routing. g. Complete station records, trouble reports, log entries, etc., in accordance with established procedures. 4-32. Baseband Fault When it is determined that the entire transmission media baseband has deteriorated, the station Techi4-18 f. Measure the group regulation pilot transmission media monitor jacks with selective voltmeter and spectrum analysis at both terminals. Make certain that the levels are in accordance with appropriate subsystem block and level diagram and that they are free of noise. frequency signal, as is excessively noisy indications at the (i.e., 10 minutes), the Technical Controller should notify the appropriate DOCC and request rerouting instructions for any priority circuits that may be involved. h. Connect a frequency selective voltmeter and a spectrum analyzer to the transmission media baseband monitor jack to test for interference or man-made noise at the receive terminal. Observe the baseband signal for noise pulse or interfering signals. i. Work with the maintenance personnel as they alternately deactivate the individual receive while observing the baseband signal and multiplex performance to determine the frequency sensitivity (interfering effect) of unwanted signals or to isolate a defective receiver. j. Request alternate deactivation of the frequency diversity transmitters to ensure that unwanted signals or noise are not caused by the distant end transmitters. Direct maintenance personnel to perform transmitter and common baseband equipment tests to verify normal operation. k. If the fault has not been isolated at t&is point in the test procedure, request deactivation of both transmitters. Monitor the receiver output on the oscilloscope and the automatic gain control (AGC) meters. The presence of noise spikes or pulses indicates either radio interference or local man-made noise. Noise may be caused by many things, including defective antenna TM 11-5895-1012-10 o r e q u i p m e n t to more than one receiver. l. Direct maintenance personnel to perform receiver common base-band equipment tests to verify noroperation. m. Test the common circuitry of the multiplex terminal. n. When the malfunction has been isolated and cornotify the distant Technical Controller of the of the problem and request removal of the test signal. If necessary perform additional out-of-service testing to ensure that all circuits meet specified o. Restore user service to normal when the corrective action has cleared the malfunction. p. Complete station reports, trouble reports, log entries etc., in accordance with the established procedures. 4-33. Dc Fault Isolation When the Technical Controller discovers that one or more dc circuits are not operating properly, in-service monitoring tests should be performed in accordance with established station procedures to determine if a single channel or the entire VFCT group is faulty. If the entire VFCT group is affected, the Technical Controller must continue monitoring to determine whether the fault is within the voice frequency sub system, the multiplex channel equipment, or the local or distant VFCT equipment. If the fault is not in the VFCT equipment, the controller should refer to paragraphs 4-28 through 4-32 and apply the applicable procedures. Multichannel faults not involving the voice frequency subsystem or multiplex channel equip ment are limited to send or receive VFCT equipment. The Technical Controller should proceed immediately to effect isolation of the fault within the portions of the VFCT which are common to all channels. Single dc channel faults may be located by coordinating with the distant station to selectively eliminate each portion of the circuit which is performing properly. In-station monitoring procedures may often locate the fault to a general area which will permit a modification of the fault isolation procedures and attack the problem directly, either by substitution of equipment by patching or replacement of equipment. Out-of-service testing procedures or in-station test and alignment procedures can then be applied to locate and correct the fault. a. When it is determined that one channel of a multichannel VFCT system is unuseable, the Technical Controller should proceed as follows: (1) Coordinate with the distant Technical Control Facility to restore service on a spare channel or preempt a low priority user. If a low priority user is preempted, have the distant Technical Controller notify the user of preemption of the circuit. (2) Request the distant Technical Control Facility to send a teat signal on the faulty channel. (3) If the results of the test procedure are unsatisfactory at a certain point, the trouble will have been isolated to that particular area. In such a case, proceed as follows: (a) In coordination with the distant technical control, determine which equipment is at fault (for example, VFCT keyer or converter, line conditioning equipment, etc.). (b) Coordinate the equipment repair or alignment required tocorrect the fault. (c) If equipment is found to be unuseable, coordinate with station maintenance personnel for its replacement. (d) After repair or replacement, perform the appropriate test to ensure proper operation of the circuit. (e) Notify the user that the fault has been cleared, and restore service to the normal route. Service shall always be returned to the normally assigned channel at the earliest possible time. (4) When the test signal from the distant TCF is satisfactory, request a test signal from the distant sub scriber to determine whether the fault is between the distant subscriber and distant Technical Control Facility or between the local TCF and its subscribers. The Technical Controller at both ends of the circuit should monitor the subscriber’s test signal, and in that way isolate the fault area. (a) Coordinate the repair or alignment required to provide service between the DCS Station and the local subscriber. (b) Perform the appropriate tests to ensure proper operation of the circuit over the lines between the DCS Station and the local subscribers. (c) Notify the user that the fault has been cleared, and restore service to the normal route. (5) Complete station records, trouble reports, log entries, etc., in accordance with the established procedures. b. When it is determined that all channels within a multichannel VFCT system are unuseable, the Technical Controller shall proceed as follows: (1) Notify the distant Technical Control Facility to block user input on all channels. Notify users that the circuit has failed, and deactivate all traffic equipment. (2) The cause of failure could be in the voice frequency channel or in the VFCT equipment. Perform the voice frequency fault isolation procedures as described in paragraph 4-30. (3) If the results of (2) above are satisfactory, request the distant TFC sent a test signal on specific channels. Channels 1, 8, and 16 of the VFCT equip ment are preferred test tone channels. Proceed as follows: 4-19 TM 11-5895-1012-10 (a) Check the level of the multichannel VFCT tones at the voice frequency patch panel and instruct (4) When the trouble has been isolated and corrected by coordinating the maintenance necessary to restore operations, notify the distant Technical Controller of the nature of the problem and restore the . user circuits to normal. (5) If the malfunction cannot be corrected in a reasonable length of time (Le., 10 minutes), the Technical Controller should notify the appropriate DOCC and, if required, request rerouting instructions for priority channels pending the completion of repairs. (6) Complete station records, trouble reports, log entries, etc., in accordance with established procedures. 4-34. Commercial Procedures Initial testing will be conducted to determine whether the reported trouble is in the local terminal portion, distant terminal portion, or in the leased portion of the circuit. So that such testing can be accomplished, it is essential that all parties concerned definitely understand the extent of their responsibility. a. Military terminals are responsible for establishing proper circuitry, correct operation of equipment and circuitry from and to the terminals where the commercial carriers responsibility begins at the interface points. b. The commercial carrier is responsible for establishing and maintaining the type of service requested by the military between the designated terminals. This includes troubleshooting and restoration of service up to the interface points. The following action will be taken: (1) Call the appropriate commercial circuit control office for trouble reporting. (2) Provide an account of the trouble indicated according to results obtained from tests. (3) The nature and indications of common troubles encountered on leased or military circuits are listed below. The terms listed have been chosen so that the nature of the trouble will be understood by commercial carrier personnel throughout the world who have contact with the DCS. (a) No receive current or signal. (b) Cannot receive ringing current. (c) Levels too low. (d) Excessive noise. (e) Intense crosstalk. 4-20 (3) Telephone numbers. (4) Date, time and trouble number. (5) Station reported to. (6) Names or initials of coordinator. d. Inquiries concerning status of reported carrier will provide information as concerning the status of the circuit The commercial carrier may include probably location of trouble switch to an alt-route, but they are not required to furnish more detailed information. Only information concerning restoral of circuit or in-effect between the commercial 4-35. Examples of Voice Channel Fault Isolation Procedures There are a number of acceptable methods of isolating a faulty link in a communications channel. Two methods are explained in this paragraph . The first method (discussed in a and b below) requires the isolation procedure to begin at the point of fault recognition. Each site clears itself of any responsibility for fault by sponsible TCF to isolate the fault over the whole communications chain by having the signal from the local TCF looped back and tested at various points in succession along the chain a. Noise Burst on Multiplexed Through Circuit. The procedure followed is outlined in flow-chart fashion in tant Technical Controller is notified figure 4-7. Th that noise bursts are being received by a subscriber. The complaint has been verified at the distant end, and that station has been cleared of causing the trouble. The noise bursts are incoming to the distant Technical Control Facility, and that Technical Controller requests that the local Technical Controller clear the local station of being the cause of the noise bursts. The local controller is responsible for simply checking the circuit through the site to determine if the fault source is in the station, reporting back to the distant station, and correcting the fault if necessary. Following is an example of an isolation procedure for this type of fault: (1) At the equal level patch panel farthest from the complaining subscriber, connect a loudspesker to the receive monitor jack of the affected circuit. (2) Listen for the noise burst complaint. TM 11-5895-1012-10 action to clear the problem, responsible Technical Control Facility of the source of the trouble, action taken, and complete station records in accordance with established procedures. (9) If, after maintenance personnel have checked the equipment, the source of trouble is not at the local station, notify the responsible TCF so that fault isolation may continue at points closer to the signal (10) Standby to assist in patching or other fault isolation tests if it should be necessary. (11) If noise is not present, then the source of trouble is somewhere between this point and the complaining subscriber. This includes the local station transmit multiplex and transmission media equipment Figure 4-71. Noise Burst on multiplexed through circuit, fault isolation flow chart (sheet 1 of 2) 4-21 TM 11-5895-1012-10 (12) Perform the tests described in (1) through (3) above at the equal level patch panel closest to the complaining subscriber. (13) If noise bursts are present, then the trouble is located somewhere within the local TCF. The responsible Technical Control Facility and local maintenance personnel should be notified. Take action to clear the fault and report in accordance with established station procedures. (14) If noise bursts are not present, request that local maintenance check the transmit side of the circuit towards the complaining subscriber for the possible sources of trouble. Should the local station transmit side be faulty, take action to have the trouble cleared and consider what action must be taken, similar to that outlined in (7) above. (15) Notify the responsible TCF of the source of trouble, action taken and complete station records in accordance with established procedures. with established procedures. b. Noise Burst on a Local Subscriber Circuit. The procedure followed is outlined in flow-chart fashion in figure 4-8. The Technical Controller is notified by a connected subscriber that frequent noise bursts are being received. The local Technical Controller has responsibility for coordinating fault isolation procedures at distant station which may be involved; but, first if must be determined whether the local station is at fault. An immediate decision must be made whether to patch the affected circuit over to a spare channel This decision is influenced by the priority of the circuit Figure 4-72. Noise burst on multiplexed through circuit, fault isolation flow chart, (sheet 2 of 2) 4-22 TM 11-5895-1012-10 encountered, proceed to (6) below. (3) Notify local maintenance personnel of the problem and request the multiplex equipment be is local. If the fault is at this point indicates the fault lies between the level patch panel and the signal source. This trouble by substituting for the defective channel equipment. If the noise is found to be across the entire group, consider patching at the group level, replacing defective equipment, or if the outage may be long in duration, (i.e., longer than 10 minutes), rerouting circuits in accordance with established procedures and priorities. (5) After the fault is cleared, restore any rerouted Figure 4-81. Noise burst on a local subscriber circuit, fault isolation flow chart (sheet 1 of 3). 4-23 TM 11-5895-1012-10 circuits to their normal path. Complete station records in accordance with established procedures. (6) If the local station proves not to be the source of trouble, as the responsible TCF, proceed with established fault isolation procedures through coordination with other TCF's which defective circuit. (7) When the trouble rerouted circuits to their son for and location of Figure 4-82. Noise burst on a local subscriber circuit, fault isolation flow chart (sheet 2 of 3). 4-24 TM 11-5895-1012-10 (11) Notify local maintenance personnel of the problem. When the troulbe has been cleared, remove any patches which have been established. Complete station records in accordance with established procedures. (12) If noise is not encountered at the equal level or primary patch panels, the fault is in the subscriber's terminal equipment or the tie-cable. . (13) Notify local maintenance personnel and locate a spare cable pair. (14) If extended circuit outage time is expected, Figure 4-83. Noise burst on a local subscriber circuit, fault isolation flow chart (sheet 3 of 3) 4-25 TM 11-5895-1012-10 (15) After the fault has been cleared, remove any patches which have been established and complete station records in accordance with established procedures. c. Fault Isolation of a VF Subscriber Circuit by the Loop-Back Method. This procedure followed is outlined in flow-chart fashion in figure 4-9. The Technical Controller is notified by a local subscriber that the circuit level is not correct. A spare channel is available and the circuit is patched over onto the spare circuit so that the normal path can be available for out-of-service testing. The basic procedure is to clear the local station Figure 4-91. 4-26 send point of the same channel under test at the equal level patch panel. (3) The local Technical Controller inputs a 1 Hz test tone on the send circuit at a level of 0 dBm at the equal level patch panel. The same test tone should Vf subscriber circuit loop-back, fault isolation flow chart (sheet 1 of 2) TM 11-5895-1012-10 that channel's receive circuit on panel at a level of 0 dBm. If the leg of the defective channel has If the level is not correct, the fault has isolated between the two TCF’s and the trouble can be turned over to maintenance personnel. (4) If the tone looped back is received at the proper level, the distant TCF is requested to remove the loop back patch and the next TCF further toward the signal source is requested to perform a similar patch. Again the local TCF inputs a 1000 Hz tone at 0 dBm and measures the level of the looped back tone. Following this procedure, trouble can be isolated between any two equal level patch panels in the channel. (5) When the fault has been located in the defective circuit, the tasks is turned over to maintenance personnel to clear the trouble. After the fault has been cleared, restore the circuit to its normal path, obtain the reason for the fault and location, and complete station record% in accordance with established pro= cedures. 4-36. Examples of a Dc Circuit Fault Isolation Procedures a. Open Circuit Condition. The station Technical Control Facility is notified by a connected telegraph subscriber that incoming traffic has been interrupted and that the printer has started to run open. Reference to the circuit layout record card indicates that the subscriber circuit is connected by cable to a nearby military installation. The most likely reason for the condition reported is a break in the dc loop cawed by failure of the loop battery, an open connection at the subscriber terminal, a defect in the cable, or an electrical failure of the receiving equipment. (1) Loop Battery Check. The Technical Controller Figure 4-92 . Vf subscriber circuit loop-back method, fault isolation flow chart (sheet 2 of 2) 4-27 TM 11-5895-1012-10 should check the appropriate fuse panel (or associated alarm output) to verify that no failure has occurred in the loop current distribution system serving the subscriber loop and associated DLIU. If, in fact, a blown fuse alarm is received, the line should be checked for a short circuit. If no short is detected, the DLIU should be substituted and refused. (2) Open Connection at Subscriber Terminal. If no failure in the loop battery supply is detected, the Technical Controller should: (a) Locate the jack appearances of the subscriber circuit at the dc primary patch panel and connect a current meter into a monitor jack appearance of the transmit circuit (receive circuit of subscriber) to measure the loop current. (b) If no loop current is observed, connect a voltmeter into the receive monitor jack appearance of the defective circuit on the dc equal level patch panel. Measure for a steady mark condition from the VFCT equipment. (c) If a steady mark condition is obtained, substitute the DLIU through patching operations. Perform the test in (a) above. If no loop current is measured, proceed to(g) below. (d) If loop current is measured, notify maintenance personnel of the defective DLIU. (e) Complete station records in accordance with established procedures. (f) After maintenance personnel have either repaired or replaced the defective DLIU, return the circuit to its normal routing. (g) If no loop current was measured in (c) above, the TCF interface equipment is not at fault. The break is somewhere in the dc loop between the station and the subscriber. (h) Return the normal interface equipment to the circuit by removing the patchcords. (i) Isolate the defective subscriber loop from the in-station circuits by inserting a shorting-type dummy plug in the line transmit jack on the dc primary patch panel. (j) Request that user maintenance personnel check the continuity of the subscriber loop. (k) Upon verification that maintenance personnel have located and corrected the fault, insure that the normal TCF interface equipment is connected to the subscribers circuit. (l) Remove the dummy plug from the line transmit jack to reconnect the subscriber to the in-station circuit. (m) Measure the loop current at the dc primary patch panel to ensure the circuit is operating normally. (n) Complete station records in accordance with established procedures. (3) Defective Cable. The Technical Controller is notified that the reason for the open circuit condition is 4-28 a break in the cable between the DCS station and the subscriber. The report indicates that the cable will be out-of-service for some period of time. The Technical Controller reviews the area circuit records and they indicate that an alternate link is not available, or feasible, between the two communicating locations. Fur ther, it is not practicable to copy the incoming traffic at the TCF for use by the subscriber. The Technical Controller should take the following action: (a) Contact the distant Technical Control Facility and request that traffic be stopped to the sub scriber until the fault has been cleared. (b) Insert a dummy plug into the line transmit jack (the subscribers receive circuit from. the TCF) at the dc primary patch panel. This will isolate the sub scriber loop from the in-station circuit. (c) Upon notification by maintenance personnel that the cable has been repaired, the Technical Controller should remove the dummy plug from the line transmit jack at the dc primary patch panel to reconnect the subscriber loop to the in-station circuit. (d) Notify both the subscriber and the distant TCF that the circuit is ready for the passing of traffic. (e) Complete station records in accordance with established procedures. (4) Defective Subscriber Terminal Equipment. The Technical Control Facility is notified by maintenance personnel that the reason for the open circuit condition is an electrical failure in the receiving equipment at the subscriber terminal. The Technical Controller should take the following actions: (a) Insert a dummy plug into the line transmit jack (subscribers receive circuit from the TCF) at the dc primary patch panel to isolate the subscriber loop from the in-station circuit. (b) Notify the distant TCF that the circuit is out-of-service and stop traffic from being transmitted to this subscriber. (c) Upon notification by maintenance personnel that the equipment failure has been corrected, the Technical Controller should remove the dummy plug from the line transmit jack appearance at the dc primary patch panel to reconnect the subscriber loop to the in-station circuit. (d) Provide a Fox test as required, so that main= tenance personnel can ascertain that the receiving equipment is adjusted properly. (e) Complete station records in accordance with established procedures. b. Defective VFCT Channel Equipment. The Technical Control Facility is notified by a connected sub scriber that service has been interrupted on the receive circuit. The Technical Controller initiates fault isolation procedures. A zero indication is shown when a voltmeter is inserted in a monitor jack of the subscriber receive channel at the dc equal level patch panel. TM 11-5895-1012-10 The Technical Controller then actuates the cut-key of the receive channel on the dc equal level patch panel. If a cut-key is not available, the Technical Controller inserts a dummy plug into the receive channel jack appearance at the dc equal level patch panel. This action applies hold battery current to the loop, which prevents the receive equipment from running open. The Technical Controller can then proceed with the following fault isolation procedure to determine if the fault exists in the VFCT channel equipment, either in the lo= cal station or at a distant terminal. (1) Consult the station circuit files and identify the voice frequency and tone channel assignments of the dc subscriber circuit which is in trouble. (2) Place the selector switch of the teletype carrier test set to the designated tone channel, and connect the unit to the voice frequency equal level patch panel LINE transmit jack serving that channel of the VFCT equipment. (3) Patch the dc output of the VFCT terminal at the dc equal level patch panel to a distortion analyzer, distortion test set or a monitor teleprinter. Jack appearances for these items of equipment appear on the miscellaneous/interbay jackfields of the dc test bays. If teletype signals are not received at this point, a failure in the local VFCT channel equipment is indicated. If the VFCT passes the test signal, then the fault lies in the voice frequency area or at the distant terminal (c below). (4) If the local VFCT equipment fails the test in (3) above, request that station maintenance personnel check the VFCT channel equipment serving the sub scriber loop. (5) The local Technical Controller should coordinate the transfer of the subscriber circuit to a spare channel, if necessary with the distant station Technical Controller. (6) Upon correction of the fault, the local Technical Controller should take action to return the sub scriber circuit to its normal routing. To prevent unnecessary loss of traffic on the circuit, the patchcords at both ends of the circuit should be removed simultaneously. (7) Complete station records in accordance with establishedprocedures. c. Failure at Distant Terminal. If signals are detected during the test in b(3) above, and the local voice frequency channel equipment serving the VFCT check good, a failure in the VFCT at the distant station is indicated. The local Technical Controller should do the following: (1) Contact the Technical Control Facility at the distant VFCT terminal and request that he continue the fault isolation procedure through the distant station. This procedure must be continued by all Technical Control Facilities involved with the circuit until the fault has been isolated. (2) Upon isolation of the fault at a distant station, the responsible Technical Controller should coordinate efforts to restore service to the subscriber. The temporary transfer of the circuit to a spare channel may be required. (3) Upon notification that the necessary repairs have been made, the responsible Technical Controller should assist the distant Technical Controller(s) in the restoration of normal service to the subscriber. (4) Complete station records in accordance with established procedures. d. Channel Degradation. The local Technical Control Facility is notified by a connected subscriber that a teletypewriter machine has started to produce garbled page copy. The report states that the error rate is serious enough to render incoming messages unintelligible. The local Technical Controller should proceed as follows: (1) Subscriber Loop Check. The local Technical Controller should patch a monitor teleprinter into a MONITOR jack appearance of the complaining sub scriber receive channel at the primary dc patch panel to determine the quality of the signals passing through to the subscriber loop. An alternate method is to patch a distortion analyzer into the subscriber circuit at this point to determine the type of distortion causing the signal degradation. This information is most useful in many instances in identifying the origin of a fault condition. Illustrations of normal and distorted teletype signals are contained in the instruction manual for the distortion analyzer. (2) Range Setting Check. If the telegraph signals are copied without garbling during the subscriber loop check, the reported fault condition may be caused by an improper range setting of the subscriber teletype machine and this should be checked. If the copy is garbled proceed to (3) below: (a) Request the subscriber to standby for a test transmisssion to evaluate the adjustment of the teletype machine. (b) Patch a pattern generator output into the LINE jack appearance of the subscribers receive circuit (transmit from the TCF to the subscriber) at the primary dc patch panel. Transmit a Fox test message to the subscriber station. The range control of the sub scriber teletypewriter machine should be adjusted by maintenance personnel to the midpoint of the range over which perfect page copy is obtained. (c) Upon correction of the fault, complete station records in accordance with established procedures. (3) DLIU Check. If the monitor teleprinter produces garbled page copy when patched into the sub scriber circuit, the Digital Line Interface Unit should be checked for faulty operation. The Technical Con4-29 TM 11-5895-1012-10 troller should proceed as follows: (a) Patch the monitor teleprinter into the MONITOR jack appearance of the subscriber’s receive circuit at the dc equal level patch panel. A defective DLIU is indicated if perfect page copy is obtained at this point. If not proceed to (4) below. (b) Temporarily replace the normal DLIU with a spare unit through patching operations. (c) Request that local maintenance personnel repair the defective unit. (d) When the repaired DLIU is returned to the normal channel assignment, the Technical Controller should remove any temporary patches which were made to restore service to the subscriber. (e) Complete station records in accordance with established procedures. (4) VFCT Channel Equipment Check. If the monitor teleprinter connected in (3)(a) above produces garbled page copy, the isolation procedure should continue following the procedure outlined in b above. (5) Distant Terminal Check. If the degraded signal is present in the voice frequency signal ((4) above) a defect in the VFCT equipment at a distant station is indicated and the fault isolation should continue following the procedures outlined in c above. 4-37. Circuit Status The duty supervisor of the Technical Control Facility must know at all times the status of circuits and equipment removed from service because of failure or sub standard performance. Positive action must be taken to ensure that: a. Notification is made when a circuit is determined to be below acceptable quality standards and is to be removed from service to restore it to an acceptable level. This notification should include the status of the following actions: (1) The appropriate control offices have been notified. (2) That service has been restored using a spare channel. (3) That a spare channel is not available, and service to the user has been temporarily interrupted. (4) That a spare channel is not available, and service is restored by preemption of a lower priority user. The prerempted circuit must be identified by CCSD. b. When user service must be interrupted, the Technical Controller coordinates with the local maintenance activity for initiation of immediate repair action. c. Periodic progress reports on the restoration of service will be provided to the duty supervisor so that he can assure that the circuit is returned to service as 4-30 rapidly as possible. 4-38. Restoration Individual circuits are restored in accordance with their assigned restoration priority. a. R&oration of service to users can basically be accomplished by repairing or replacing faulty equip ment, rerouting the circuit around the disrupted segment of the circuit by using spare facilities, or by preempting a lower priority circuit to make a higher priority circuit good. In order to maintain continuity of service for all users of the DCS, the correction of equipment should be used in lieu of preempting another working circuit when the time required by each method is nearly the same. Where trouble in a high priority circuit has been localized to the transmission media between two circuit end points and lower priori= ty circuitry exist between these two points, the lowest priority circuit(s) should be preempted if this will restore the higher priority circuit in substantially less time than the other methods of restoration. b. To assist the Technical Controller in visualizing the additional possible reroute paths available, block diagrams will be prepared at each Technical Control Facility for the area of interest, showing links between connected stations and any appropriate extension that would permit a reroute to be made. These diagrams should be maintained in a conspicuous location. c. C-reference data will be prepared to permit proper designation of facilities required during coordination for the r&oration of service. For example, commercial numbers will be used to identify circuits to commercial agencies. The cross-reference file will be maintained in a position readily accessible to the Technical Controller on duty. d. Within the DCS, Technical Controllers will, when accomplishing control action& refer to circuits by CCSD, and will refer to trunks by the DCS trunk nator. In all cases, it is essential that Technical Controllers use equipment nomenclature and language that is readily understood. e. The primary responsibility for reroute action normally rests with the receiving Technical Control Facility. The appropriate control office will be notified when reroute action cannot be accomplished. f. When the trouble on the original path of a rerouted circuit has been cleared and tested, the Technical Control Facility initiating the reroute will take action to have the circuit returned to its original use and configuration. Also, this TCF will take action to return the path, used for the reroute to its original use and configuration. TM 11-5895-1012-10 Section V. MANCESTANDARDS AND TEST MEASUREMENTS 4-39. General This section contains the DCS Technical Schedules, which provide circuit performance parameters. Chapter 6 contains the associated test descriptions for test measurements of DCS facilities, systems, or circuits. In addition this section provides guidance for testing DCS circuits to determine compliance with DCS Technical Schedule criteria and to determine circuit signaling performance. parameters, unless specifically guaranteed by contract, are provided by the carrier on a “will-strive, nonguaranteed" basis; however, a circuit cannot be removed from service because of failure to meet these other parameters unless the user reports unsatisfactory service and a nonguaranteed parameter is causing the unsatisfactory service. c. Leased circuits terminating in a military Technical Control Facility or Patch and Test. Facility at both ends will be tested for the parameters in table 4-2 for the type of service specified in the TSO. The common carrier will meet guaranteed parameters and will be requested to meet all other parameters. If the common carrier declines to meet these additional parameters and the user states that the circuit provides acceptable service, the CCO will accept the circuit and identify all out-of-tolerance parameters in the in-effect report. d. Leased circuits terminating in a military TCF or PTF at one end and a commercial test facility at the other end will meet the parameters guaranteed by tariff or contract, as applicable. The TCF or PTF will request the carrier to test for all other parameters in table 4-2 for the type of service specified in the TSO. The CCO will identify in the ineffect report those parameters the carrier declines to test. e. Commercial circuit parameters and identifiers vary throughout the world and it is impractical to at tempt to list all of them in this manual. Table 4-3 contains parameters and identifiers generally recognized by the U.S. common carriers for conditioned circuits. DCA areas will compile a listing of commercial circuit parameters and identifiers used within their area of re- Technical Schedules 4-40. The DCS Technical Schedules are itemized listings of all the common services and circuit parameters provided by the DCS. The DCS Technical Schedules apply to all government-owned circuits within the DCS with the exception of voice circuits provided over high frequency radio. Table 4-1 describes the type of service provided by each circuit performance code. Tables 4-2 and 4-3 are a list of performance parameters required by each parameter code. Table 4-4 is a list of leased service performance parameters which common carriers generally provide. These tables are samples and current procedural documents should be checked for current requirements. a Government-owned circuits are required to meet each parameter for the type of service specified in the TSO. Government-owned circuits unable to meet the DCS parameters, even with optimum transmission adjustment, will meet the requirements specified by the DCA. b. Leased circuits will meet all parameters guarancontract, as applicable. U.S. common tly guarantee frequency response and envelope delay distortion parameters only. All other Table 4-1. DCS Technical Schedules 4-31 TM 11-5895-1012-10 Table 4-1. DCS Technical Schedules-Continued 4-32 TM 11-5895-1012-10 Table 4-1. DCS Technical Schedules-Continued Table 4-2. DCS Technical Schedules Circuit Parameters 4-33 TM 11-5895-1012-10 Table 4-2. DCS Technical Schedules Circuit Parameters - Continued Table 4-3. DCS Technical Schedules Circuit Parameters Z1, Z2, and Z3 4-34 TM 11-5895-1012-10 Table 4-3. DCS Technical Schedules Circuit Parameters Z1, Z2, and Z3 - Continued 4-35 TM 11-5895-1012-10 4 8 12 16 2 0 24 2 8 32 3 6 4 0 4 4 4 8 52 56 60 64 68 72 FREQUENCY (KHz) NOTES: 1. ABOVE CURVE REPRESENTS ENVELOPE DELAY REQUIREMENTS. LIMITS ARE NOT SPEClFlED BELOW 6 KHz. 2. IF THE ENTIRE CIRCUIT CONSISTS OF PROPERLY AMPLITUDE EQUALIZED TWISTED PAIR CABLE, FROM WHICH ALL LOADING COILS AND BRIDGE TAPS HAVE BEEN REMOVED, NO DELAY EQUALIZATION SHOULD BE REQUIRED. GIVEN THE CORRECT FREQUENCY RESPONSE OVER THE RANGE OF .01 TO 50 KHz (NO DISCONTINUITIES OR SHARP ROLLOFFS), ENVELOPE DELAY WILL NOT NORMALLY BE AN ITEM FOR CONCERN ON CABLE PAIRS. 3. SHOULD THE CIRCUIT CONTAIN CARRIER FACILITIES, DELAY EQUALIZATION MUST BE EMPLOYED SUCH THAT THE DELAY VERSUS FREQUENCY RESPONSE OF THE CIRCUIT IS A SMOOTHLY AND CONTINUOUSLY INCREASING FUNCTION OF FREQUENCY, WHICH FALLS WITHIN THE SHADED AREA OF THIS FIGURE. EL3Z0046 Figure 4-10. Relative envelope delay vs frequency limits. 4-36 TM 11-5895-1012-10 Table 4-4. Commercial Technical Schedules Note 1. Schedule 4A parameters are the same as C1 parameters Note 2. Schedule 4B parameters are the same as C2 parameters Note 3. Schedule 4C parameters are the same as C3 parameters Nate 4. CCITT M.102 parameters are the same as C2 parameters, except that loss IS relative to 800 Hz instead of 1000 Hz Note 5. DCS Technical schedules S1 and D1 compare to Commercial C2 Technical schedules for frequency response and envelope delay die tortion. Note 6 DCS Technical schedule S3 compares to Commercial C5 Technical schedules for frequency response and envelope delay distortion 4-41. Test Descriptions Each Test Description (TD) includes the test arrangement, equipment configuration, and test procedure. With the exception of those parameters which are not applicable to all types of channels, each analog parameter test description includes date for testing the following types of channels: voice frequency chanchannels (0-50 kHz), 48 kHz channels 4-42. Digital Distortion Standards The digital distortion standards contained in this paraan extract from other publications. It is that some equipment currently used in the will nut operate within these standards. Each DCS facility using substandard equipment should determine the technical reasons why the equipment will not operate within established standards, and determine a standard which the equipment can consistently meet. As a minimum, equipment will at least meet the specifications contained in the technical or manufacturer manual, where specified. Requests for waivers from DCA performance standards will be sub mitted through appropriate DCA regions to cognizant DCA areas for approval, with an information copy to appropriate O&M activities. Requests will contain the technical justification for the waiver and the proposed interim standard for the equipment. DCA areas will review the technical data and proposed and where appropriate grant the waiver. If necessary, full resolution of the waiver request will be carried to the Director, DCA. a. Application. These standards apply to out-ofservice testing performed at the TCF patch bay. Tech 4-37 TM 11-5895-1012-10 nical Control Facilities should determine distortion thresholds for the particular equipment and circuits with their station and forward recommendations to appropriate DCA field activities for concurrence, with an information copy to appropriate Operation and Maintenance activities. When distortion thresholds are exceeded, the technical controller will initiate corrective action to remove the equipment from service. For example, when the maximum output distortion allowed on a transmitter-distributor (out-of-service) is 1 percent, corrective action will be initiated when the output distortion exceeds 4 percent. Corrective action may include changing transmitter-distributors, repairing equipment on line, or using a spare circuit. b. Equipment Capability. If the design capability of equipment listed in subsequent paragraphs permits operation at maximum distortion limits lower than those specified, the maximum limits specified in the technical manual or manufacturer handbook will apply. c. VFCT. With the transmit and receive terminals connected back-to-back, sending and receiving loops properly terminated, and all transmit tones at proper levels, random undistorted signals will be keyed simultaneously into each sending loop at the maximum modulation rate of the terminal design. The maximum distortion measured in the receiving loops will not exceed 4 percent total peak telegraph distortion at modulation rates up to and including 75 baud. d. Transmitting Equipment Output Distortion. The output distortion (all types) of electromechanical, electronic, or composite transmitting devices (either sequential or coincidental selection) will not exceed. one percent. e. Electromechanical Receiving Devices. Electromechanical receiving devices shall be capable of tolerating signal distortion as follows: (1) Total peak distortion:45 percent. (2) Bias distortion: 45 percent. (3) End distortion: 45 percent. (4) Cyclic distortion 22.5 percent. f. Electronic-Input Receiving Devices. Receiving de vices utilizing electronic input circuitry shall be capable of tolerating signal distortion as follows: (1) Total peak distortion: 49 percent. (2) Bias distortion: 49 percent. (3) End distortion: 49 percent. (4) Cyclic distortion: 24.5 percent. g. Electromechanical Polar Relays. Total distortion introduced into the transmission facilities, attributable to the relay, shall be less than two percent. h. Electronic Polar Relays. Total distortion intro duced into transmission facilities, attributable to the relay, shall be less than one percent. i. Differential Phase Shift Keying (DPSK) Modems. DPSK modems &all operate in accordance with per 4-38 formance requirements when the isochronous distortion of the input data is less than or equal to 10 percent measured at the data signaling rate of the modem. The isochronous distortion of the output data signal when measured at the operating data signaling rate shall be less than four percent. j. Digital Regenerative Repeaters. (1) Synchronous repeater input will accept the following distortion limits and provide an output signal with not more than three percent distortion, of which not more than one-third (one percent) is bias: (a) Total peak distortion: 49 percent. (b) Bias distortion: 49 percent. (C) Cyclic distortion: 49 percent. (d) Fortuitous distortion: 49 percent. (2) Start-stop repeater input will accept the following distortion limits and provide an output signal with not more than three percent distortion, or which not more than one-third (one percent) is bias: (a) Total peak distortion: 49 percent. (b) Bias distortion: 49 percent. (c) Cyclic distortion: 24.5 percent. (d) Fortuitous distortion: 24.5 percent. k. Punched Card Readers. Punched card readers will produce not more than one percent distortion of the signal element for electronic devices and 3.5 percent distortion for electromechanical devices, as measured in relation to the theoretically correct unit interval duration. l. Card Punch. The card punch will operate without error if the input distortion is less than the following: (1) Total peak distortion: 49 percent. (2) Bias distortion: 49 percent. (3) End distortion: 49 percent. (4) Cyclic distortion: 24.5 percent. m. Magnetic Tape Readers. Total distortion attributable to the magnetic tape reader will not exceed one percent at the output of the intermediate equipment. n. Magnetic Tape Recorders. Magnetic tape recorders will operate without error if the input distortion is less than the following: (1) Total peak distortion: 49 percent. (2) Bias distortion: 49 percent. (3) End distortion: 49 percent. (4) Cyclic distortion: 24.5 percent. o. Paper Tape Readers. (1) Electromechanical Equipment. The total output distortion will not exceed one percent for the standard 5-unit code character interval, and 3.5 percent for the standard 8-unit code character (ASCII). (2) Equipment Incorporating Electronic Output Circuitry. The total output distortion will not exceed one percent. p. Paper Tape Punches. Electromechanical paper tape punches incorporating electronic serial input cir TM 11-5895-1012-10 cuitry will operate without error if the input distortion is less than the following: (1) Total peak distortion: 49 percent. (2) Bias distortion: 49 percent. (3) End distortion: 24.5 percent. q. Link Encryption Equipment. Link encryption equipment will accept distortion (all types) up to 49 percent and provide an output signal with not more than one percent distortion. 4-43. Conduct of Tests The Circuit Control Office designated in the TSO is responsible for circuit activation, to include the scheduling, supervising, and reporting of circuit tests. The CCO will ensure that each segment of the circuit is properly aligned and tested against the applicable standards prior to conducting end-to-end testing. Intermediate TCF's on the circuit path will be responsive to directions issued by the CCO. a. End-to-end testing, as used in this technical manual refer to the point nearest the user terminals at each end of the circuit where the capability exists to performance required testing. In many cases, this will be the serving TCF or PTF. In some cases, end-to-end testing may be performed at the user terminal. Technical Control Facilities will determine the point at which required end-to-end test measurements are made for each circuit. When tail segments between the TCF and the user cannot be readily tested on a scheduled basis, arrangements will be made to test the user loop from the TCF to determine loop characteristics. Data obtained from this test will be retained in the TCF for reference during subsequent Quality Control testing or troubleshooting. b. Leased circuits are considered to be one segment, regardless of the number of breakout points in the circuit. Common carriers are responsible for providing required signals at the point where government and commercial facilities interface. 4-44. Test Reporting a. The CCO will submit an In-Effect Report or Exception Report as specified in established procedures. The following instructions pertain to sub mission of the reports: (1) Subsequent to submitting an In-Effect Report, the Circuit Parameter Test Report, DD Form 1697 will be forwarded in accordance with existing directives to the DCA activity that issued the TSO and the cognizant DCA region. (2) When an exception report must be submitted, the CCO will include in the message, as a part of the statement of the problem, an extract of the appropriate portion of the Circuit Parameter Test Report. These extracts will include identification of the test that failed to meet specifications, specific measurements obtained and comments, e.g., change in audio frequency + 20 Hz, measurement made at station Alpha from station Bravo (include further comments on nature of trouble and estimated time to repair). b. When it is determined as a result of out-of-service Quality Control testing that circuit or equipment parameters cannot be brought within test and acceptance specifications, the CCO or affected Technical Control Facility will forward the following information to appropriate DCA and operation and maintenance elements. DCA, in cooperation with lateral O&M elements, will ensure that required technical assistance is provided to return the circuit or equipment test and acceptance specifications. (1) Identification of circuit or equipment. (2) Test and acceptance measurements for those parameters failing to meet specifications. (3) Out-of-service Quality Control test measure ments for those parameters failing to meet specifications. (4) Remarks. 4-45. Recording Test Results a. DD Form 1697 (Circuit Parameter Test Report) will be used to record the results of testing performed for initial acceptance of service and for each reconfiguration of the circuit. A copy of this test report will be filed with the corresponding TSO at the cognizant DCA region or area and maintained in the Technical Control Facility files. DD Form 1697 may be overprinted as required by DCS operating elements. b. DD Form 1697 will not be forwarded to DCA or operation and maintenance elements when scheduled or unscheduled quality control testing is performed unless tasked to do so for specific circuits and for specific periods of time. However, a record of quality control tests and test results will be maintained in the Technical Control Facility files. Local forms may be used provided they contain all information required for DD Form 1697. Section VI. CIRCUIT PERFORMANCE AND QUALITY CONTROL TESTING 4-46. Introduction by detecting and correcting adverse trends before the a. Effective worldwide service to all users of the user service is affected. DCS requires each segment of the system to be opb. Quality control is that function by which pererated and maintained at its specified operating level. formance is measured and the results are then comThe concept of quality control and performance pared against established standards. Optimum monitoring is to prevent interruption to user service performance can be achieved and maintained by 4-39 TM 11-5895-1012-10 thorough testing and analysis of test results. An effective quality control program consists of scheduling prescribed tests, measuring specific parameters, comparing recorded measurements against applicable standards, trend analysis and directing corrective actions where indicated. 4-47. Quality Control of Governmentowned Circuits a. In-Service Quality Control Testing. In-service quality control testing is performed regularly on all active circuits within the Technical Control Facility. Measurements are made using high impedance bridging to prevent interruption of user service. Normal user traffic signals, telephone supervisory parameters which can be measured without interruption of service and then compared to levels normally found at the transmission level point of the circuit under test. (1) The technical controller analyzes the test results to determine if corrective action is required to bring the circuit within system standards or the original circuit acceptance parameters. When required, corrective action can be accomplished by rerouting the circuit, equipment substitution on the normal path, or, when neither is possible, obtaining a user release of service in order to take the circuit out of-service for maintenance action. (2) If the user does not want to release the circuit because of traffic load or mission requirements and states that the degraded circuit is providing satisfactory service, the technical controller will make arrangements with the user for release of the circuit as soon as traffic conditions or mission requirements permit. (3) Appropriate maintenance elements and connected TCF's or PTF’s will be advised of the substandard condition of the circuit and of the projected downtime. b. Out-of-Service Quality Control Testing. It is the responsibility of the TCF designated as Circuit Control Office to schedule out-of-service quality control testing on all circuits over which responsibility has been assigned. Periodic out-of-service testing permits endto-end realignment of circuits to meet applicable DCS circuit parameters. Out-of-service testing usually requires the user to release the circuit for a specified amount of time. Where at all possible a reroute will be provided depending upon the circuit priority. c. Communications Equipment. Scheduled quality control testing of all communications equipment sup porting the DCS, including spares, is required. Communications equipment may be located in other sections of the DCS Station; i.e. radio and carrier, automatic switching centers, communications centers, or within the TCF itself. In most cases, there is a Patch and Test Facility associated with the section involved. 4-40 All quality control testing of communications equip ment will be conducted with the knowledge and permission of the TCF supervisor on duty. Operational equipment will be tested off-line after the completion of regularly scheduled maintenance and in conjunction with the appropriate maintenance personnel. Where possible, equipment will be tested under maximum loading, such as all VFCT equipment channels being keyed with test messages. A review of trend analysis should be made by TFC and maintenance personnel prior to the test. This will identify channels that have had most of the outages and degree of maintenance adjustments since the last scheduled test. This analysis may show the possibility of deteriorating components in the equipment and that this test period may require a closer examination of the item of equipment than is normally required during routing testing. 4-48. The basic requirement for quality control testing of leased communications circuits is identical to that required on Government owned circuits, with the following exceptions: a In-Service Quality Control Testing. When it is determined through in-service testing that a circuit does not meet parameters contracted for in the Communications Service Authorization (CSA), one of the following actions must be initiated: (1) If the user states the circuit is not providing satisfactory service, the circuit will be logged out-ofservice with the commercial carrier for immediate corrective action. (2) If the user states that the circuit is providing satisfactory service and the commercial carrier cannot provide immediate corrective action or reroute, corrective action will be scheduled for a time mutually agreeable to the user and the carrier. b. Out-of-Service Quality Control Testing. The Circuit Control Office will coordinate quality control test schedules with commercial carriers to ensure that the carriers will have personnel and *test equipment available to participate in quality control tests and initiate corrective actions if the circuit does not meet parameters contracted for in the CSA. 4-49. Quality Control a. In-Service Test Schedules. Tests and frequency of tests shown in table 4-5 are considered the minimum required. Detailed schedules will be such that these minimum requirements are satisfied. The TCF may increase the frequency of testing as necessary to ensure required operations. Test requirements may be satisfied by use of automatic sensing equipment which measure circuit parameters and provides a record copy of readings or alarms which sound when present TM 11-5895-1012-10 program will be used as the criteria for developing the exceeded. quality control testing schedule. However, if deemed rvice Test Schedules. Out-of-service, necessary, the frequency of testing may be increased end-to-end quality control tests, will be scheduled by by the TCF to ensure optimum operating conditions. the responsible CCO. The tests and frequency of tests Quality control testing of equipment ensures that the shown in table 4-5 are considered the minimum equipment meets the technical specifications conessential. Selected out-of-service, end-to-end quality tained in the applicable technical manuals. control tests, as determined by the TCF, are required d. Analysis of Test Results. Analysis of test results after a transmission media failure, when equipment or and of equipment failures might indicate a need to lines are suspected of being faulty, when directed by revise test schedules. If a particular type of equipment the appropriate DOCC or operation and maintenance or circuit is causing little or no outage between quality element, or when deemed necessary by the TCF to control tests, an increase in the time interval between ensure optimum operation. scheduled tests might be appropriate. Conversely, if c. Communications equipment Test Schedules. many outages are incurred or frequent adjustments Quality control testing of operational and spare equip are required on the equipment or circuit, a decrease in ment appearing on the TCF of PTF patch panels will the time interval between scheduled tests might be apbe performed on a scheduled basis. The time interval propriate. currently used by the operation and maintenance activities in their established preventive maintenance Table 4-5. Circuit Quality Control Schedule Legend: 72-Every 72 Hours: Q-Quarterly; S-Semiannual: A-Annual Note 1. V2 parameters will be used for out-of-service testing of spare unconditioned VF channels and circuits. unless otherwise specified. Note 2. Certain voice circuits utilize tone-on-while-idle supervisory signaling and will normally have a signal. either speech or tone. present Measurements will be made at the monitor jack AS false rings will be caused by breaking the supervisory tone The normal speech level is - 12 VU at the 0 dBm TLP. The normal tone-on-while-idle signal level IS - 20 dBm0 Note 3 Testing of channels under the PMP satisfies this requirement Note 4. Normal day-today technical control actions satisfy in-service test requirements for active dc circuits Spare dc circuits will be tested for total peak distortion at least once every 72 hours. use of a spare dc circuit for reroute or establishing an on-call circuit satisfies this requirement 4-41 TM 11-5895-1012-10 Table 4-6. Noise Power Conversion 4-42 TM 11-5895-1012-10 Table 4-6. Noise Power Conversion - Continued 4-50. Performance Monitoring The DCS Performance Monitoring Program encompasses monitoring the operation of the DCS transmission links using critical operating parameters as performance indicators, and the analysis of the information received to develop performance trends. Each DCS Technical Control Facility will participate in this program in accordance with established guidelines and directives. 4-51. Trend Analysis Analysis of quality control data will be performed by the Technical Control Facility on as near a real-time basis as possible to identify degrading trends. a. In-service quality control tests are the best tools to identify degradation because measurements can be taken and recorded without interrupting the user. Measurements of each quality control test are compared with the measurements taken in the past. If a definite change is noted, but the circuit is still providing satisfactory user service, it should be flagged as a special interest circuit. One substandard measurement does not constitute a trend. If, after several measurements are taken, further changes are indicated, a degrading trend is evident and corrective action should beinitiated. b. Trend analysis is not limited to quality control measurements. Trends can be detected from the number of outages over a given period of time. The minimum number of outages per circuit, of course, is not definable. The length of outage should not be considered in this analysis. c. Trend analysis can be expanded to determine whether large number of outages are occurriug in the same time frame. This analysis should be performed if large numbers of outages cannot be reduced after repeated attempts to locate and correct the deficiency. d. To simplify the analysis effort, data may be transposed from worksheets to a line or bar graph or some other management tool, such as a computer runoff to give the history and present quality of a given circuit or channel at a glance. Comparison with all other channels of a particular group will indicate the general quality of the group. 4-43 TM 11-5895-1012-10 e. Figure 4-11 through 4-13 are examples of typical graphs that may be used for trend analysis. 4-52. Excessive Signal Levels Frequently, excessive signal levels are introduced into the DCS from the user equipment. Excessive signal levels from just a small number of users can cause crosstalk across the baseboard of an entire system. Whenever excessive signal levels are detected, as a result of inservice quality control testing or as a result of a user complaint, immediate action will be initiated by the technical controller to locate the source. The serving TCF will immediately notify the violating user, direct his attention to the provisions of established directives, and request that immediate action be taken to correct the deficiency. If the user continues to violate signal level limits, the serving TCF will deny service to the user until proper signal levels are by the user. Actions of this nature will be properly documented and immediately reported to the appropriate Docc and operation and maintenance activities. Denial of service for this reason should be done judiciously and then only with approval of the Technical Control Facility shift supervisor. As a rule of thumb, the following criteria may be applied: a. If the signal level is within 3 dB of the correct level, the serving TCF should initiate normal coordination to correct the level. b. If the signal level is between 3 dB and 6 dB above the correct level, the user must correct the level within 15 minutes or the TCF will deny service. c. If the signal level is more than 6 dB above the correct level, the TCF will immediately deny service until the user provides the correct level. Figure 4-11. Sample distortion trend analysis chart. Figure 4-12. Sample noise level trend analysis chart. 4-44 EL3Z0048 TM 11-5895-1012-10 Figure 4-13. Sample number of outages trend analysis chart. 4-53. Improper Termination of Circuits Circuits improperly terminated and user terminals modified without appropriate Technical Service Order action will be denied access to the DCS, in accordance with the procedures in paragraph 4-52. Access will be denied the violating user until the terminations are in accordance with the TSO. It is the responsibility of the user to provide proper interface or terminations for circuits entering the DCS. 4-54. Quality Control and Performance Monitoring Management monitoring is the responsibility of each technical controller within the . The technical control shift supervisor is responsible for ensuring that scheduled testing is performed. The shift supervisor will advise the technical control chief of any problem areas, and of any circuits of sys- tolerance, and coordination with commercial carriers when leased circuits are out of tolerance. b. The teat equipment on site is the responsibility of the Military Department operating the DCS Station. When an item of test equipment is inoperative or turned in for recalibration, and a like piece of equip ment is not available, the test equipment should he declared “mission essential” and an attempt made to obtain a replacement so that fault isolation, quality control testing, and performance monitoring functions are not impaired. c. The DCS Station will prepare quality control and performance monitoring checklists that enable any technical controller to test any equipment, circuit, or system within the facility. 4-55. Quality Control Tests Typical Quality Control Test procedures, with test setup diagrams are contained in chapter 6. The test procedures are general in nature and do not specify test equipment by commercial type number of military nomenclature. Test equipment is referred to in a generic sense, i.e., level meter, signal source (generator), phase jitter meter, etc. Substitution of the specific item of test equipment on site, should any technical controller to perform the specified Quality Control tests. 4-45 TM 11-5895-1012-10 Section VII. IMPLEMENTATION OF COMMUNICATIONS SERVICES REQUIREMENTS AND INSTATION TESTING 4-56. Telecommunications Service Orders (TSO's) The basic circuit design information for all new or changed circuits is provided in the DCA Telecommunications Service Orders (TSO's). The TSO is the authorization for DCA Headquarters of a DCA area to activate, change, or deactivate circuits or trunks, to amend previously issued TSO’s, and to effect administrative changes. The TSO gives the following information: a. Issuing office. b. The year it is issued. c. TSO serial number. d. Circuit identification. e. The sequential action being taken on the circuit. 4-57. TCF Responsibilities a. The many variations found in the configurations of DCS Station Technical Control Facilities prevent the development of precise procedures for the installation, alignment, and testing of circuits which would apply to all types of circuits and to every DCS Station. However, there are certain functional steps in activating circuits which are common to all stations. Upon receipt of a TSO, the following steps are necessary to install, align, and test the circuit. (1) Administrative processing and logging of receipt of the TSO. (2) Preparation of the detailed in-station layout designating specific cross-connects and specific equipment to be utilized as required by the TSO. (3) Preparation of work order, or instructions, to section(s) or personnel responsible for performing instation wiring. (4) Performance of in-station wiring check by Technical Control Facility personnel on in-station circuitry and associated transmission links in conjunction with adjacent TCF’s. (5) Notification to appropriate control offices that in-station and adjacent link tests are complete and meet required criteria. (6) Performance of circuit alignment tests by TCF personnel on in-station circuitry and associated transmission links in conjunction with adjacent TCF. (7) Participation in end-to-end testing and directed by the appropriate control office. (6) Administrative recording and reporting of action required or completed in conjunction with the installation. Managerial procedures for accomplishing the above functions are left to the discretion of the individual station. However, close coordination is important between the section preparing the in-station 4-46 wiring layout and the Technical Controller performing the in-station tests to prevent errors in the circuit installation and to ensure that required technical parameters have been met. b. Upon completion of the in-station installation, the Technical Controller is responsible for ensuring proper alignment of the in-station portion of the circuit as well as the adjacent link(s). Continuity and transmission level adjustments on the in-station installation will be performed first. When the in-station portion of the circuit is properly installed and adjusted, the input and output levels on all external transmission channels assigned to the circuit must he adjusted to the proper value. Additional checks as required to ensure proper functioning of conditioning and signaling equipment will be made. When the internal and external alignment and checks are complete, an overall recheck of the complete installation will be made. In the specific cases where a PTF is located between the Technical Control Facility and the user, the TCF is responsible for ensuring that the transmission levels, signaling and conditioning of the circuit are properly adjusted between the user and the PTF. c. Each circuit installed in the DCS will be tested in accordance with the criteria specified in the DCS Technical Schedule for the type of circuit in the TSO. Upon notification from all intermediate TCF's that in-station and adjacent segment tests are complete, the Tech&al Control Facility designated as Circuit Control Office will initiate end-to-end tests of the circuit. Each of the specific tests are required to ensure compliance with the DCS circuit technical schedule parameters. Refer to applicable DCA documentation to determine the DCS Technical Schedule and Circuit Parameters for the circuit that has been installed. d. The Technical Control Facilities concerned will immediately notify the CCO or the ICO, when, for any reason, delays are encountered or anticipated in activation of circuits. The notification will contain de tailed information on reasons for delay or inability to activate circuits. Pertinent recommendations on methods of providing service should also be included. This information may be used by the CCO in preparation of an exception report. e. Deactivation of circuits will be accomplished after coordination with all concerned and records will be retained in an inactive or “dead” file for 6 months before destruction or disposition in accordance with establishedrequirements. f. Completion of activation records and reports is the responsibility of the Technical Controller. TM 11-5895-1012-10 4-58. Procedures for Changing and Building Circuits a are: , actions necessary to change a circuit (1) Patch around the in-house portion of the existing circuit, or terminate the circuit legs on the line side of the patch panels with 600-ohm terminating plugs. (2) Remove from the universal conditioning equipment shelf the modules of the string to be (3) Remove cross-connects and rewire the IDF in the conditioning equipment bay to form the desired string. (4) Change cross-connections on the voice frequency, combined distribution frame (CDF) to obtain the desired jack appearances and multiples, cable, or VFCT assignments necessary. (5) Replace the conditioning modules. (6) Perform the necessary in-house quality control checks (refer to chapter 6). (7) Remove patches or plugs installed in (1) above. (8) Perform the necessary station-to-station tests (refer to chapter 6). b. Generally, actions necessary to build a new circuit are: (1) Form the desired conditioning equipment string by cross-connecting at the IDF above the bay. (2) Cross-connect at the VF CDF to connect the string to the desired patch panels (insert dummy plugs in all line jacks if the patch panels are already wired to a multiplex or channel VFCT, or cable pair). (3) Plug in all conditioning equipment modules. (4) Perform the necessary in-house quality control checks (refer to chapter 6). (5) Cross-connect the patch panels to the appropriate multiplex or VFCT channel or cable pair at the VF CDF (or remove dummy plugs if previously wired).(6) Perform the necessary out-of-service stationto-station quality control tests (refer to chapter 6). 4-59. Sample Circuit Building Procedure The sample process for building voice frequency circuit configuration figure 4-14 is as follows: a Voice Frequency Circuit Connections. Refer to the cut-sheet table 4-7 and figure 4-14 which illustrate the following cross connection procedure. (1) Connect the Equ Out (Drop) side of the receive equal level patch panel circuit terminated on block H17J, row 1, pins 3 and 4 to the signaling frequency (SF) unit receive input (line aide) terminated at bay 4.1 on block TB3, row 1 pins E and F by cross-connecting black H17J, row 1, pins 3 and 4 to block V9F, row 2, pins 1 and 2 respectively and at bay 4.1, TB3, row 1, pins E and F to TB9, row 1, pins E and F respectively. (2) Connect the Equ In (Drop) side of the transmit equal level patch panel circuit terminated on block H17K, row 1, pins 3 and 4 to the DF unit transmit output (line side) terminated at bay 4.1 on block TB3, row 1 pins C and D by cross-connecting block H17K, row 1, pins 3 and 4 to block V9F, row 1, pins 3 and 4 respectively and at bay 4.1, TB3, row 1 pins C and D to TB9, row 1, pins C and D respectively. (3) Connect the SF unit receive output (Drop) side terminated at bay 4.1 on TB3, row 1, pins H and J to the amplifier (Al) input terminated at bay 4.1 on TB3, row 2, pins A and B by cross-connecting TB3, row 1, pins H and J to TB3, row 2, pins A and B respectively. (4) Connect the SF unit transmit input (Drop) side terminated on TB3, row 1, pins A and B to the Pad (P2) output terminated on TB3, row 3, pins H and 9 by cross-connecting TB3, row 1 pins A and B to TB3, row 3, pins H and J respectively. (5) Connect the SF unit E&M leads terminated at bay 4.1 on TB3, row 1, pins K and L to the ringdown converter (RDC) E&M leads terminated at bay 4.1, TB3, row 1, pins K and L to TB3, row 6, pins K and L respectively. (6) Connect the amplifier (Al) output terminated at hay 4.1 on TB3, row 2, pins C and D to the pad (P1) input terminated at bay 4.1 on TB3, row 3, pins A and B by cross-connecting at bay 4.1, TB3, row 2, pins C and D to TB3, row 3, pins A and B respectively. (7) Connect the pad (P2) input terminated at hay 4.1 on TB3, row 3, pins E and F to the amplifier (A2) output terminated at bay 4.1 on TB3, row 2, pins H and J by cross-connecting at bay 4.1, TB3, row 3, pins E and F to TB3, row 2, pins H and J respectively. (8) Connect the pad (P1) output terminated at hay 4.1 on TB3, row 3, pins C and D to the echo suppressor receive input (line) terminated at bay 4.1 on TB3, row 4, pins E and F by cross-connecting at bay 4.1, TB3 row 3, pins C and D to TB3, row 4, pins E and F respectively . (9) Connect the amplifier (A2) input terminated at bay 4.1 on TB3, row 2, pins E and F to the echo suppressor transmit output terminated at bay 4.1, TB3, row 4, pins C and D by cross-connecting at bay 4.1 on TB3, row 2, pins E and F to row 4, pins C and D respectively . (10) Connect the echo suppressor receive output terminated at bay 4.1 on TB3, row 4, pins H and J to the 2/4 wire terminating set receive input terminated at bay 4.1 on TB3, row 5, pins A and B by cross-connecting at bay 4.1, TB3, row 4, pins H and J to row 5, pins A and B respectively. (11) Connect the echo suppressor transmit input terminated at bay 4.1 on TB3, row 4, pins A and B to the 2/4 wire terminating set transmit output minated at bay 4.1, on TB3, row 5, pins C and D by crossconnecting at bay 4.1 on TB3, row 4, pins A and B to row 5, pins C and D respectively. (12) Connect the 2/4 -wire terminating set’s 2 wire 4-47 TM 11-5895-1012-10 line terminated at bay 4.1 on TB3, row 5, pins K and L to the E&M/25 Hz ring down converter's Send In (T1, R1) line terminated at bay 4.1 on TB3. row 6, pins A and B by cross-connecting at buy 4.1, TB3, row 5, pins K and L, to TB3, row 6, pins A and B respectively. (13) Connect the 2/4 wire terminating set terminated at bay 4.1 on block TB3, row 5, pins E and F to the VF primary patch panel terminated on block H13K, row 1, pins 3 and 4 by cross-connecting at bay 4.1, TB3, row 5, pins 3 and F to TB9, row 5, pins E and F respectively and block V9F, row 10, pins 1 and 2 to block H13K, row 1, pins 3 and 4 respectively. (14) Connect the E&M/25 Hz ringdown converter Receive In line terminated at bay 4.1 on TB3, row 6, pins C and D to the VF primary patch panel equipment side (T1, R1) terminated on block H13K, row 1, pins 3 and 4 by cross-connecting at bay 4.1 TB3, row 6, pins C and D to TB9, row 6, pins C and D respectively and block H13K, row 1, pins 3 and 4 to block V9F, row 11, pins 3 and 4 respectively. b. Voice Frequency Level Adjustments. The InStation test will be run before connecting to the multiplexer equipment. Adjust levels from the equal level patch panel to the primary patch panel as follows: (1) At the equal level patch panel, the receive and transmit levels will be at 0 dBm. (2) The SF-2600 has approximately 0 dB insertion loss and will not affect the circuit level. (3) Adjust amplifiers 1 and 2 for a 12 dB gain and pads 1 and 2 for an 8 dB loss to compensate for the 4 dB insertion loss of the 4 wire termination set and allow an operation level of 0 dBm at the voice frequency (4) The E&M/25 Hz converter and echo su has approximately 0 dB insertion loss and will not affect the circuit levels. c. In-Station Testing After the correct circuit levels have been obtained, perform the in-station test procedures contained in chapter 6. To use a test on a 2 wire circuit, use the same two-wire circuit for both transmit and receive tests and omit the terminating resistor when necessary. d. Multiplexer Equipment Connections. Refer to the sample cutsheet (table 4-7) and cross-connect as follows: (1) Connect the multiplexer receive circuit terminated on block V32K, row 1, pins 3 and 4 to the equal level patch panel DEM IN (line) terminated on block H17J, row 1, pins 1 and 2 by cross-connecting block V32K, row 1, pins 3 and 4 to block H17J, row 1, pins 1 and 2 respectively. (2) Connect the multiplexer transmit circuit terminated on block V32K, row 1, pins 1 and 2 to the equal level patch panel MOD OUT (Line) terminated on block H17K, row 1, pins 1 and 2 by cross-connecting block V32K, row 1, pins 1 and 2 to block H17J, row 1, pins 1 and 2. c. Final Testing. Perform the out-of-service quality control (station-to-station) testing contained in chap ter 6. If the circuit checks out in accordance with the testing and conforms to established parameters, then report the circuit ready for operation in accordance with established procedures. Table 4-7. Sample cutsheet for 2-wire voice circuit t (25 Hz signaling and echo suppressor control) 4-48 TM 11-5895-1012-10 Table 4-7. Sample cutsheet for 2-wire voice circuit (25 Hz signaling and echo suppressor control) - Continued Section VIII. ACCEPTABILITY OF NEW EQUIPMENT 4-60. General There is a need for continuing improvement in transmission quality. Therefore, integration of new equip ment into the DCS is accomplished in some areas of the world every week. Technical and operational compatibility is always an important consideration. 4-61. technical Control Facility Responsibilities a. The Technical Control Facility chief will: (1) Supervise an evaluation test of the equipment to be cutover before it is placed on-line for DCS traffic. This will include as a minimum, but not be limited to, the following (a) All quality control tests that are normally performed on the subject item of equipment. (6) Back-to-back and looped tests will ‘be performed as appropriate. (c) Preparation of quality control records for the new equipment to include posting of all test information. A copy of the initial tests will be provided the appropriate DCA area or region. (2) Coordinate with appropriate control offices and other DCS Stations, as required, the addition of the new equipment into the system. (3) Supervise the cut-over of all circuits to the new equipment. (4) Supervise the testing of all circuits that require conditioning to ensure that the proper transmission parameters are maintained. b. Special attention must be given to protection of service to users that have control, error detection, and alarm devices on their circuits. Full coordination must be made prior to any cut-over or testing to maintain operations without damage to communications equip ment. c. Where service must be interrupted for cut-over of new equipment, the established procedures must be followed. Cut-over plans will be submitted to the appropriate DOCC in sufficient time to review and coordinate the plan. 4-62. Test and Acceptance Acceptability of new systems and subsystems usually require the services of test and acceptance (T&A) teams. In some cases, one terminal and sometimes both, may terminate in a facility where Technical Control Facility personnel are not assigned, but where the facility is aligned as a system or subsystem reporting responsibility of a Technical Control Facility. In all cases it is imperative that personnel of that Technical Control Facility be members of the T&A teams accept 4-49 TM 11-5895-1012-10 Sample voice frequency circuit configuration connection diagram (sheet 1 of 3). Figure 4-141. Sample Sample voice frequency circuit configuration connection diagram (sheet 2 of 3) Figure 4-142. Sample 4-50 TM 11-5895-1012-10 Figure 4-143. Sample voice frequency circuit configuration diagram (sheet 3 of 3). 4-51 TM 11-5895-1012-10 4-52 TM 11-5895-1012-10 CHAPTER 5 STATION MAINTENANCE 5-1. Operator's preventive maintenance is the systematic care, servicing, and inspection of equipment to prevent the occurence of trouble, to reduce downtime, and to assure that the equipment is serviceable. a Systematic Care. The procedures given in paragraphs 5-3, 6-4, 5-5, and 5-6 cover routine systematic care and cleaning essential to proper upkeep and operation of the equipment. Item numbers indicate the sequence of minimum inspection requirements. b. Preventive Maintenance Checks and Services. The preventive maintenance checks and services charts (para 5-3 through 5-5) outline functions to be performed at specific intervals. These checks and services are designed to maintain Army Equipment in a combat-serviceable condition; that is, in good general (physical) condition and in good operating condition. The charts indicate what to check, how to check, and the normal conditions. Defects discovered during operation of the technical control facility will be noted far future correction, to be made as soon as equipment can be freed from service. Operation will be stopped immediately if a deficiency is noted which would damage the equipment. If the defect cannot be remedied by the operator, higher category of maintenance or repair is required. 5-3. Operator Daily Checks 5-4. Operator Weekly Preventive Preventive Maintenance Maintenance 5-2. Preventive Maintenance Checks and services Periods Preventive maintenance checks and services of the technical control facility are required daily, weekly and quarterly. a Paragraph 5-3 specifies the checks and services that must be performed every day that the equipment is used, and under the special conditions listed below: (1) When the equipment is initially installed. (2) When the equipment is reinstalled after removal for any reason. (3) At least once a week, if the equipment is maintained in standby condition. b. Paragraph 5-4 specifies additional checks and services that must be performed on a weekly basis. c. Paragraph 5-5 specifies other checks and services that must be performed on a quarterly basis. Checks and and Services Services 5-1 TM 11-5895-1012-10 5-5. Operator Quarterly Preventive Maintenance Checks and Services 5-6. Cleaning a. Materials Required. The following materials are required for cleaning the equipment in the technical control facility: (1) Trichloroethane. (2) Soft, lint-free cloth. (3) Liquid detergent. (4) Nylon bristle brush. WARNING The fumes of trichloroethane are toxic. Provide thorough ventilation whenever used. DC NOT use near an open flame. Trichloroethane is not flammable, but exposure of the fumes to an open flame or hot metal surface converts them to a highly toxic phosgene gas. Inhalation of this gas could result in serious injury or death. b. Methods. Perform the following procedures to 5-2 clean the equipment in the technical control facility: (1) Inspect exterior surfaces of the equipment for dust, dirt, grease and fungus. (2) Remove the dust and loose dirt with a soft, clean cloth. (3) Remove grease, fungus, and ground-in dirt from metal parts with a cloth dampened (not wet) with trichloroethane. (4) Remove dust or dirt from plugs and jacks with a soft brush. CAUTION Do not press on the METER FACE when cleaning. Damage to the equipment may result. (5) Clean the front panel, meter face, and controls of the equipment using a soft, clean cloth. If necessary, dampen the cloth with water or mild detergent for more effective cleaning. TM 11-5895-1012-10 CHAPTER 6 TEST PROCEDURES 6-1. Introduction a. Scope of Testing. Test procedures in this chapter cover station to station (quality control) and in-station (maintenance) testing. However, testing at a particular facility should not be limited to the testing described by this chapter nor should all facilities necessarily perform all the tests described in this chapter. The number and types of tests performed at a specific technical control facility depends on the type of service provided by the facility and on the technical services schedule for that facility. The tests in this chapter are primarily intended for checking multiplex voice-channel breakout to multiplex voice-channel breakout links with single or multiple hop paths. b. Quality Control Tests. Quality control or station to station tests should be performed regularly as specified in chapter 4. These tests are used for evaluation of the performance of a circuit and in end-to-end circuit fault isolation. c. Maintenance Tests. Maintenance or in-station tests should be performed prior to putting a circuit into operation if the circuit has just been built or repaired. They are also used in troubleshooting station equipment. 6-2. Description of Test Equipment The test equipment described below is required to perform the tests specified by this chapter. The descriptions given are of a general nature since the test equipment at each facility varies with the functions of that facility and the services it provides. a. Noise Measuring Test Set. The noise measuring test set is used to measure noise and signal levels to -85 dbm. It has a frequency range of 50 to 5000 Hz and may be balanced for either 600 or 900 ohms impedance. If a Universal Transmission Measuring System is available, it may be used in place of the noise measuring test set. b. Transmission Test Set. The transmission test set a test oscillator, an attenuator, a matching and a level meter. It has the following performance characteristics: (1) Minimum frequency range of 20 Hz to PO KHz (2) Frequency-Amplitude response of less than 0.5 db variation over 20 Hz to 10 KHz into a matching resistive load. (3) Minimum output level range of + 5 to -30 dbm. (4) Output impedance of 600 to 900 ohms, balanced. (5) Input of level meter is 600 or 900 ohms. c. Envelope Delay Test Set. The envelope delay test set consists of a transmitter and receiver. It measures signal delay and amplitude versus frequency. It has the following performance characteristics: (1) Carrier frequency adjustable from 200 Hz to 600 Hz. (2) Modulation frequencies of 25, 83 1/3, and 250 Hz. (3) Amplitude accuracy of ± 0.5 db. (4) Delay accuracy of ±25 microseconds at 25 Hz or ± 2 microseconds at 250 Hz modulation. d. Frequency Counter. The frequency counter has a range of 200 to 4000 Hz and a sensitivity of 100 millivolts. It has an accuracy of ± 1 count. e. Frequency Selective Voltmeter. The frequency selective voltmeter operates in the range of 5 to 1600 KHz with an accuracy of 0.5 db. It is sensitive from -90 to +30 dbm and has two bandwidths (250 or 2500 Hz). f. Impulse Noise Counter. The impulse noise counter has three adjustable ranges and is capable of counting impulses above the three adjusted levels. It is equipped with a timer and a storage capacity of at least four digits while counting up to 10 counts per second minimum. g. Oscilloscope. The oscilloscope may be either a single or a dual trace with a minimum rise time of 10 microseconds or less. h. Phase Jitter Meter. The phase jitter meter measures the phase jitter of a single frequency signal. It has a minimum level range of -30 to 0 dbm with a measuring range of at least 0 to 30 degrees peak to peak jitter. The readout is in degrees peak to peak jitter. i. Dual-Channel Recorder. The dual-channel recorder is capable of measuring 0.1 to 500 volts with a sensitivity of 0.1 volts per millimeter. The chart speed is adjustable. j. Signal Test Set. The signal test set measures pulse speed and percent of break. The test set also generates pulses used to test signaling circuits and may be used as a pulse repeater or converter. k. Test Set, Teletypewriter AN/GGM-15(V)1. This test set provides a capability for measuring signals in dc teleprinter/data loops and for transmitting digital test messages over these loops. The test set includes a 6-1 TM 11-5895-1012-10 signal generator, a signal distortion analyzer, and an oscilloscope. These items are described below: (1) Signal Generator SG-860/GGM-15(V). This unit generates data and telegraph signal outputs with controlled distortion at speeds up to 9600 baud. Various message options are available for Baudot or ADCII codes. (2) Signal Distortion Analyzer TS-2862/ GGM-15(V). This unit performs three major functions: distortion analysis, distortion monitoring, and error rate determination. (3) Oscilloscope OS-20/GGM-15(V). This unit is used to display the signal under analysis. l. Accessory Items. The accessory items listed below are required for some of the tests in this chapter. (1) Test Tone Source. 1000 Hz at - 10 dbm0. (2) Resistors. Two 300 ohm ± 1%, 1 watt resistors and one 150 ohm ± 1% 1 watt resistor are required. (3) Transformer. An center-tapped audio transformer with a 1:1 ratio and an 600/600 ohm impedance is required. 6-3. Test Conditions a. Patch Panels. Unless otherwise specified, station to station tests will utilize two equal level patch panels while in-station tests will utilize one equal level and one primary patch panel. b. Service Conditions. Unless otherwise specified, the circuit to be tested will he out of service. However, it will be aligned and conditioned for the circuit characteristics and transmission levels specified in the applicable TSO. 6-4. Idle Channel (Residual) Noise Test (fig. 6-1) a. Purpose. This test will measure idle channel (residual) noise on a circuit between stations or within a station and will determine circuit compliance with standard operating requirements. Idle channel or residual noise is a combination of all of the disturbances occurring within the channel bandwidth and includes noise caused by nonlinearities, crosstalk, and thermal effects. b. Test Equipment. The following test equipment is required to perform this test: (1) Noise Measuring Test Set. (2) Terminating plugs (600 ohms) and patch cords. c. Station-to-Station Test. Contact distant station and arrange for one station to act as transmitter and one as receiver. Perform the procedure below and then reverse roles and repeat the procedure. (1) Transmitting Circuit. If the local station is to act as transmitter, prepare the transmitting circuit shown in figure 6-1. (2) Receiving Circuit. If the local station is to act as receiver, prepare the receiving circuit shown in fig6-2 ure 6-1. (3) Procedure. The receiving station will measure and record the noise level indication. This measurement will be taken with the Noise Measuring Test Set set for C message filtering and will be measured in dbrnc. (4) Performance Standard. Refer to the Technical Services Schedules (table 4-2) for the maximum allowable noise for the channel being tested. The noise measured during this test will not exceed the level specified by the Technical Services Schedule. d. In-Station Test. In-station testing is accomplished in the same manner as station to station testing except the local station acts as both transmitter and receiver. 6-5. Frequency Response Test (fig. 6-2) a. Purpose. This test will measure frequency response of a circuit either between stations or within a station and determine circuit compliance with the standard operating requirement. Frequency response is the capability of a system or component to pass a group of frequencies with the original amplitude relationship relatively intact. b. Test Equipment. The following test equipment is required to perform this test: (1) Transmission Test Set. (2) Noise Measuring Test Set. (3) Terminating plugs (600 ohms) and patch cords. c. Station-to-Station Test. Contact distant station and arrange for one station to act as transmitter and one as receiver. When test has been completed reverse roles. (1) Transmitting Circuit. If the local station is to act as transmitter, prepare the transmitting circuit shown in figure 6-2 and set the equipment as follows: (a) Patch panel impedance selectors at 600 ohms. (b) Patch panel frequency control at less than 5 KHZ (c) Transmission Test Set for 1000 Hz, -10 dbm0 output to the transmit circuit. (2) Receiving Circuit. If the local station is to act as receiver, prepare the receiving circuit shown in figure 6-2 and set the equipment as follows: (a) Input selector set for 600 ohms. (b) Filter selector set for 15 Hz. (c) Sensitivity set for 0. (3) Procedure. While the transmitting station varies the frequency and holds the input level constant, the receiving station will record level readings on the Noise Measuring Test Set for the following frequencies: 300 Hz, 400 Hz, 500 Hz, 600 HZ, 700 Hz, 800 Hz, 1000 Hz, 1200 Hz, 1400 Hz, 1600 Hz, 1800 Hz, 2000 Hz, 2200 Hz, 2400 Hz, 2600 Hz, and 3000 Hz (4) Performance Standard. Maximum deviation TM 11-5895-1012-10 Figure 6-1. Idle channel (residual) noise teat. from 1000 Hz if - 2 + 6 db. d. In-Station Test. h-station testing is accomplished in the same manner as station-to-station testing except the local station acts as both transmitter and receiver. 6-6. Envelope Delay Distortion Test (fig. 6-3) a. Purpose. This test will measure circuit delay distortion of circuits between stations or within a station and determine compliance of circuits with the standard operating requirements. Circuit delay distortion is the distortion caused by differing amounts of delay for each of the various frequencies comprising the intelligence carrying signal. This is tested by transmitting several narrow band modulation envelopes and measuring the difference between the longest envelope delay and the shortest envelope delay. This difference is called the envelope delay distortion. b. Test Equipment. Two envelope delay test sets are required if the teat is to be conducted within a station. One envelope delay test set is required for each station the test is to be conducted between two stations. c. Station-to-Station Test. Contact distant station and arrange for one station to act as transmitter and one as receiver. Perform the procedure below and then roles and repeat the procedure. (1) Transmitting Circuit. If the local station is to act as transmitter, prepare the transmitting circuit shown in figure 6-3 and set the envelope delay test set as follows: (a) Transmit and receive reference. (b) Signal level of - 10 db. (c) Carrier frequency of 2000 Hz. (d) Modulation frequency of 25 Hz. (2) Receiving Circuit. If the local station is to act as receiver, prepare the receiving circuit shown in figure 6-3 and set the envelope delay test set as follows: (a) Receive-return reference. (6) Carrier frequency of 2000 Hz. (c) Modulation frequency of 25 Hz. (3) Procedure. With the transmitting station envelope delay test set set for the reference frequency of 2000 Hz, record the delay indicated on the envelope delay test set. The transmitting station will then set the envelope delay test set for each of the frequencies. indicated in table 6-1. As each frequency is obtained, measure the delay and calculate the difference between that delay and the delay measured at the reference frequency of 2000 Hx. This difference may be either positive (more delay than was measured at 2000 Hz) or negative (less delay than was measured at 2000 Hz). (4) Performance Standard. The maximum deviation permissible from the reference frequency of 2000 Hz is indicated in table 6-1. d. In-Station Test. In-station testing is accomplished in the same manner as station to station test ing except the local station acts as both transmitter and receiver. 6-3 TM 11-5895-1012-10 Figure 6-2. Frequency response test. 6-4 TM 11-5895-1012-10 Figure 6-3. Envelope delay distortion test. 6-5 TM 11-5895-1012-10 Table 6-1. Envelope Delay Measurements d. In-Station Test. In-station testing is accomplished in the same manner as station to station testing except the local station acts as both transmitter and receiver. 6-8. Minimum Longitudinal Balance Test 6-7. Audio Frequency Test a. Purpose. This test will measure maximum circuit frequency change between stations or within a station and determine compliance of circuits with the standard operating requirements. b. Test Equipment. The following test equipment is required to perform this test: (1) Noise Measuring Test Set. (2) Frequency Counter (two required for in-station test). (3) Terminating plugs (600 ohms) and patch cords. c. Station-to-Station Teat. Contact distant station and arrange for one station to act as transmitter and one as receiver. Perform the procedure below and then reverse roles and repeat the procedure. (1) Transmitting Circuit. If the local station is to act as transmitter, prepare the transmitting circuit shown in figure 6-4 and set the equipment as follows: (a) 1000 Hz Test Tone Source set for - 10 dbm0 coupled to transmit line. (b) Frequency Counter set to measure ac within .1 Hz (2) Receiving Circuit. If the local station is to act as receiver, prepare the receiving circuit shown in figure 6-4 and set the equipment as follows: (a) Frequency Counter set to measure ac within .1 Hz. (b) Noise Measuring Test Set set Hi Pass filtering and 600 ohm input. (3) Procedure. The transmitting station will measure the Test Tone Source and record the indication to the nearest .1 Hz. The receiving station will measure and record the level meter indication on the Noise Measuring Test Set. The receiving station will then observe the indication on the Frequency Meter for one minute and record this measurement. The two stations will then compare the recorded frequencies and determine the difference between them. (4) Performance Standard. The maximum permissible change between the transmitted and received frequencies is ± 5 Hz. 6-6 transmit and receive circuits and determine circuit compliance with the standard operating requirements. Any voltage that causes a current to flow in the same direction in both conductors of a circuit is a longitudinal voltage. This can be caused by extraneous voltages induced into the circuit by either electromagnetic or capacitive coupling to both conductors from other circuits, or as a result of any external electrical disturbances. This test measures of the induced longitudinal voltage on the signal voltage by introducing a known signal voltage and measuring the resulting longitudinal voltage. b. Test Equipment. The following test equipment is required to perform this test: (1) Transmission Measuring Test Set (3 required). (2) Transformer, 1:1 ratio, 600/600 ohm, audio, center-tapped. (3) Resistors, 300 ohm ± 1%, 1 watt (2 required). (4) Resistor, 150 ohm ± 1%. 1 watt. (5) Terminating plugs (600 ohms) and c. Station-to-Station Input Teat. Co station and arrange for one station to act as transmitter and one as receiver. Perform the procedure below and then reverse roles and repeat the procedure. (1) Transmitting Circuit. If the local station is to act as transmitter, prepare the transmitting circuit shown in figure 6-5 and set the equipment as fellows: (a) Transmission test sets jumpered as shown in figure 6-5 with voltmeter function switch to on. (b) Patch panel impedance selectors at 600 ohms. (c) Patch panel frequency selector at less than 5 KHz. (2) Receiving Circuit. If the local station is to act as receiver, prepare the receiving circuit shown in figure 6-5. (3) Procedure. (a) At the transmitting station, set the frequency of the Transmission Test Set No. 1 to a value near the top of the 2700 Hz). Adjust the Set No. 1 for an inpu mit input as read on Transmission Teat Set No. 3 voltmeter. Note the level in volts and label this V1. (b) Adjust the range control of Test Set No. 2 voltmeter for a suitable sensitivity, measure the low longitudinal signal across the ohm resistor. Note this level and label it V2. TM 11-5895-1012-10 Figure 6-4. Audio frequency test. 6 - 7 TM 11-5895-1012-10 (c) Remove the input signal by disconnecting Transmission Test Set No. 1 and observe Transmission Test Set NO. 2 voltmeter. If the voltage measured by Transmission Test Set NO. 2 does not drop in value when the input signal is disconnected, then the line noise is probably mashing the reading Of V2. This con&ion must be corrected before the test can be completed. (d) If the voltage measured by Transmission Test Set NO. 2 (V2) did drop in value when the input signal was disconnected then calculate the Longitudinal Balance using the following formula: Longitudinal Balance (db) = 20 Log10V1/V2. (4) Performance Standard. Minimum Longitudinal Balance is 40 db. d. Station-to-Station Output Test. Contact distant station and arrange for one station to act as transmitter and one as receiver. Perform the procedure below and then reverse roles and repeat the procedure. (1) Transmitting Circuit. If the local station is to act as transmitter, prepare the transmitting circuit shown in figure 6-6 and set the equipment as follows: (a) Transmission test set jumpered as shown in figure 6-6 with voltmeter function switch to on. (b) Patch panel impedance selectors at 600 ohms. (c) Patch panel frequency selector at less than 5 KHz. (2) Receiving Circuit. If the local station is to act as receiver, prepare the receiving circuit shown in figure 6-6 and set the equipment as follows: (a) Transmission test sets jumpered as shown in figure 6-6 with voltmeter function switches to on. (b) Patch panel impedance selectors at 600 ohms. (c) Patch panel frequency selectors at less than 5 KHz. (3) Procedure. (a) At the transmitting station, set the frequency of Transmission Test Set No. 1 to a value near the top of the audio bandwidth (approximately 2700 Hz). Adjust transmission Test Set No. 1 for a level of - 10 dbm0 as read at the receiving station on Transmission Test Set No. 3 voltmeter. Note this level and label it V1. (b) Adjust the range control of Transmission Test Set No. 2 for a suitable sensitivity and measure the voltage displayed on Transmission Test Set No. 2 voltmeter. Note this voltage and label it V2. (c) Calculate the longitudinal balance of the output circuit using the following formula: Longitudinal Balance (db) = 20 Log10V1/V2. (4) Performance Standard. The permissable minimum longitudinal balance is 40 db. e In-Station Testing, In-station testing is accomplished in the same manner as station to station 6-8 testing except the local station acts as both transmitter and receiver in both input and output tests. 6-9. Single Tone Interference Test a. Purpose. This test will measure maximum single tone interference of circuits between stations or within a station and determine circuit compliance with the standard operating requirements. These interferring tones may come from carrier leak or from nearby equipment or systems. b. Test Equipment. Test equipment required to perform this test consists of a Frequency Selective Volt meter and terminating plugs (600 ohms) and patch cords. c. Station-to-Station Test. Contact the distant station and arrange for one station to act as transmitter and one as receiver. Perform the procedure below and then reverse roles and repeat the procedure. (1) Transmitting Circuit. If the local station is to act as transmitter, prepare the transmitting circuit shown in figure 6-7. (2) Receiving Circuit. If the local station is to act as receiver, prepare the receiving circuit shown in figure 6-7 and set the frequency selective voltmeter as follows: (a) Input impedance set for 600 ohms. (b) Input attenuator set so that the maximum level of the single tone interference is included in the measuring range of the voltmeter. (3) Procedure. (a) Slowly sweep the frequency control of the frequency selective voltmeter through the frequency range of the channel under test. (b) Record the power level (in dbm) of the peaks indicated by the frequency selective voltmeter. Convert this measurement to dbm0 by allowing for the relative level of the transmission level point at which the measurement was made. (c) Convert this level from dbm0 to dbm0 using the conversion chart in figure 6-8. Read the frequency of the interferring tone from the frequency selective voltmeter and then find the conversion factor for the frequency in figure 6-8. Then, dbrnc0 = dbm0 + conversion factor. (4) Performance Standard. Refer to the Technical Services Schedules (table 4-2) for the maximum allowable noise for the channel being tested. The maximum single tone interference (measured in dbrnc0) will not exceed the level specified by the Technical Services Schedule. d. In-Station Test. In-station testing is accomplished in the same manner as station to station testing except the local station acts as both transmitter and receiver. 6-10. Impulse Noise Test a. Purpose. This test will measure impulse noise on TM 11-5895-1012-10 Figure 6-5. Longitudinal balance input test. 6-9 TM 11-5895-1012-10 Figure 6-6. Longitudinal balance output test. 6-10 TM 11-5895-1012-10 Figure 6-7. Single tone interference test. Figure 6-8. Conversion of dbm to dbrnc0. 6-11 TM 11-5895-1012-10 a circuit between stations or within a station and will determine circuit compliance with standard operating requirements. Impulse noise consists of transient waveforms of various shapes, durations, and amplitudes. It can be caused by natural disturbances such as lightning or atmospheric static, or by manmade disturbances. b. Test Equipment. The following test equipment is required to perform this test: (1) Impulse Noise Counter. (2) Terminating plugs (600 ohms) and patch cords. c. Station-to-Station Test. Contact distant station and arrange for one station to act as transmitter and one as receiver. Perform the procedure below and then reverse roles and repeat the procedure. (1) Transmitting Circuit. If the local station is to act as transmitter, prepare the transmitting circuit shown in figure 6-9. (2) Receiving Circuit. If the local station is to act as receiver, prepare the receiving circuit shown in figure 6-9 and &the impulse noise counter as follows: (a) Power switch to ON. (b) Hold switch to OFF. (c) Bridge/Term switch to Term. (d) Weighting selector to Voice. (e) Input impedance at 600 ohms. (f) Timing at 15 minutes. (g) Sensitivity controls set so that all impulse hits above the reference level specified in the technical schedules (table 4-2) will be registered or recorded. (3) Procedure. Receiving station will record all impulse hits above the reference level specified in the technical schedules (table 4-2). (4) Performance Standard. The maximum number of impulse hits permissable in the 15 minute time period is 15. d. In-Station Test. In-station testing is accomplished in the same manner as station to station test ing except the local station acts as both transmitter and receiver. 6-11. Terminal Impedance Test mit Circuit (fig. 6-10) of Trans- a. h-pose. This test will measure the terminal impedance of the transmit circuit between stations or within a station and determine circuit compliance with the standard operating requirement Terminal impedance must be kept within specifications to preclude impedance mismatch which will result in poor frequency response, excessive loss of signal power, or improper signal level measurements b. Test Equipment. The following test equipment is required to perform this test (1) Transmission Test Set. (2) Terminating plugs (600 ohms) and patch cords. c. Station-to-Station Test. Contact distant station 6-12 and arrange for one station to act as transmitter and one as receiver. Perform the procedure below and then reverse roles and repeat the procedure. (1) Receiving Circuit. If the local station is to act as receiver, prepare the receiving circuit shown in figure 6-10. (2) Transmitting Circuit. If the local station is to act as transmitter, prepare the transmitting circuit shown in figure 6-10 and set the equipment as follows: (a) Jumper the transmission test set as shown in figure 6-10. (6) Set the transmission test set patch panel out put impedance selector to 600 ohms. (c) Set the transmission test set patch panel input impedance selector for bridging‘ (d) Set the transmission test set patch panel frequency selector at less than 5 KHz. (e) Turn on the transmission test set voltmeter. (3) Procedure. Calibrate the transmission test set for 1000 Hz and a 1 volt (V1) voltmeter reading. Switch the calibrate-measure switch back to the measure position, and read the voltage (V2) on the transmission test set voltmeter. Calibrate the transmit impedance from the following expression: V1 = transmission test set open circuit output voltage V2 = t-on teat set output voltage when terminated at the receiving circuit. (4) Performance Standard. The permissable terminal impedance is 600 ohms ± 10%. d. In-Station Test. In-station testing is accomplished in the same manner as station to station testing except the local station acts as both transmitter and receiver. 6 - 1 2 . Terminal Im the terminal impedance of the receive circuit between stations or within a station and determine circuit compliance with the standard operating requirements. Terminal impedance must be kept with specifications to preclude impedance mismatch which will result in poor frequency response, excessive loss of signal power, or improper signal level measurements. b. Test Equipment. The following test equipment is required to perform this test: (1) Transmission Test Sets (2 required). (2) Terminating plugs (600 ohms) and patch cords, c. Station-to-Station Test. Contact distant station and arrange for one station to act as transmitter and one as receiver. Perform the procedure below and then reverse roles and repeat the procedure. (1) Receiving Circuit. If the local station is to act as receiver, prepare the receiving circuit shown in fig TM 11-5895-1012-10 Figure 6-9. Impulse noise test. 6-13 TM 11-5895-1012-10 Figure 6-10. Terminal impedance test for transmit circuit. ure 6-11 and set the transmission test set as follows: (a) Jumpered as shown in figure 6-11. (b) Patch panel impedance selectors at 600 (c) Patch panel frequency selector at less than 5 (d) Voltmeter function switch to on. (2) Transmitting Circuit. If the local station is to act as transmitter, prepare the transmitting circuit shown in figure 6-11 and set the transmission test set as follows: (a) Jumpered as shown in figure 6-11. (b) Patch panel input impedance selector at bridging. (c) Patch panel frequency selector at less than 5 (d) Voltmeter function switch to on. (3) Procedure. The receiving station will calibrate set for 1000 Hz and set it for 1 on the transmitting station volt- V1= 6-14 receiving station open circuit voltage V2= receiving station voltage terminated in 600 ohms (4) Performance Standard. The permissable terminal impedance is 600 ohms ± 10%. d. In-Station Test. In-station testing is accomplished in the same manner as station to station testing except the local station acts as both transmitter 6-13. Harmonic Distortion Test (fig. 6-12) measures the signal frequency and each separately and then gives a mathematical for computing the total harmonic distortion. b. Test Equipment. The following test equi required to perform this test: (1) Transmission Test Set. (2) Frequency Selective Voltmeter. (3) Terminating plugs (600 ohms) and patch c. Station-to-Station Test. Contact distant and arrange for one station to act as transmitter and one as receiver. Perform the procedure below and the reverse roles and repeat the procedure. (1) Transmitting Circuit. If the local station is to TM 11-5895-1012-10 Figure 6-11. Terminal impedance test for receive circuit. act as transmitter, prepare the transmitting circuit wn in figure 6-12 and set transmission test set as ws: (a) Jumpered as shown in figure 6-12. (b) Patch panel impedance selectors at 600 ohms. (c) Patch panel frequency selector at less than 5 KHz. (d) Turn on voltmeter. (2) Receiving Circuit. If the local station is to act as receiver, prepare the receiving circuit shown in figure 6-12 and set the frequency selective voltmeter as follows: (a) Input impedance control at 600 ohms. (b) Bandwidth to 200 or 250 Hz. (3) Procedure. Transmitting station will calibrate the transmission test set for a 700 Hz, - 10 dbm0 output. Receiving station will measure the circuit level of the fundamental (700 Hz), second harmonic (1400 Hz), third harmonic (2100 Hz), ad fourth harmonic (2800 Hz). Calculate the total harmonic distortion using the following expression: (4) Performance Standard. The maximum permistotal harmonic distortion is -40 dbm0. d. In-Station Test. In-station testing is accomplished in the same manner as station to station testing except the local station acts as both transmitter and receiver. 6-14. Composite Signal Transmission Level Test (fig. 6-13) t of operating conditions rather than a measurement of circuit parameters. As such, this test is not applicable as an in-station or maintenance test. b. Test Equipment. A noise measuring test set and patch cords are required to perform this test. c. Procedure. Prepare the test arrangement shown in figure 6-13 and set the noise measuring test set for 600 ohms impedance and for bridging. Set the filter selector for high pass filtering. The circuit being tested should be in service and the connection should be made at the VF patch panel. Read and record the indications on the noise measuring test set. d. Performance Standard. The required composite level is the reference level minus 13 dbm0. 6-15. Phase Jitter Test Using Oscila. Purpose. This test will measure phase jitter of a circuit between stations or within a station and determine circuit compliance with minimum operating requirements. Phase jitter is the instantaneous deviation from the average phase of the signal and may be caused by channel induced phase noise or by additive amplitude noise. Phase jitter may be measured using an oscilloscope or using a phase jitter meter. The procedure for measuring phase jitter using an oscilloscope is given below. The procedure for 6-15 TM 11-5895-1012-10 Figure 6-12. Transmission Test Set 6-16 TM 11-5895-1012-10 Figure 6-13. Composite signal transmission level test. itter using a phase jitter meter is 6-16. b. Test Equipment. The following test equipment is required to perform this test: (1) Test Tone Source, 1000 Hz at - 10 dbm (2 re(4) Performance S t a n d a r d . T h e m a x i m u m permissable peak-to-peak phase jitter is 15 degrees. quired). d. In-Station Test. In-station tasting is ac(2) Oscilloscope. C. Station-to-Station Test. Contact distant station complished in the same manner as station to station and arrange for one station to act as transmitter and testing except the local station acts as both transone as receiver. Perform the procedure below and then mitter and receiver. reverse roles and repeat the procedure. 6-16. Phase Jitter Test Using Phase Jitter (1) Transmitting Circuit. If the local station is to Meter (fig. 6-15) act as transmitter, prepare the transmitting circuit a Purpose. This test will measure phase jitter of a circuit between stations or within a station and deterIf the local station is to act mine circuit compliance with minimum operating receiving circuit shown in requirements. Phase jitter is the instantaneous deviation from the average phase of the signal and may . At the receiving station, patch the be caused by channel induced phase noise or by additive amplitude noise. Phase jitter may be measured by using a phase jitter meter or an oscilloscope. The procedure for use with a phase jitter meter is given below. The procedure for using an oscilloscope is given in paragraph 6-15. b. Teat Equipment. The following test equipment is required to perform this test: (1) T&Tone Source, 1000 Hz at - 10 dbm. (2) Phase Jitter Meter. c. Station-to-Station Test. Contact distant station and arrange for one station to act as transmitter and one as receiver. Perform the procedure below and then reverse roles and repeat the procedure, (1) Transmitting Circuit. If the local station is to act as transmitter, prepare the transmitting circuit 6-17 TM 11-5895-1012-10 Figure 6-14. Phase jitter testing using an oscilloscope b. Teat Equipment. The following teat equipment shown in figure 6-15. required to perform this test: (2) Receiving Circuit. If the local station is to act (1) Signal Test Sets (2 required). as receiver, prepare the receiving circuit shown in (2) Terminating plugs (600 ohms) and patch cord figure 6-15 and set the phase jitter meter as follows: c. Teat Procedure. Contact distant station and a (a) Power switch on. (b) Impedance switch to 600 ohms. range for one station to act as transmitter and one as receiver. Prepare the circuit as shown in figure 6-16 (c) Meter select switch to input level. and perform the procedure below. Then reverse roles (3) Procedures. At the receiving station, verify and repeat the procedure. that the input level is between +10 dbm and -40 (1) Place the controls of each signal test set as dbm. Then switch the meter select switch to frequency follows: and verify that frequency lock has been achieved (a) Send PPS selector to ON (10 PPS). Switch the meter select switch to 30° P-P JITTER and (b) Function switch to Test L & D. read the meter indication of peak-to-peak phase jitter. (c) TWD-L, LINE (E) key switch to OFF HOOK (4) Performance Standard. The maximum (d) TWD-D key switch to Thru & Meas. permissable peak-to-peak phase jitter is 15 degrees. (2) With the off hook signals being sent on the M d. In-Station Test. In-station testing is aclead at each station, the E lead at both ends should be complished in the same manner as station to station grounded as indicated by the extinguishing of the testing except the local stations act as both transmitter and receiver. LINE (E) lamps. (3) At both stations, switch the signal test set 6-17. Station to Station Signaling Test TWD-L, LINE (E) key switch on O (fig. 6-16) on-hook signal being sent to the M lead at each end, the E lead at both stations should be open as indicated a. Purpose. This test determines signaling perby the LINE(E) lamp at both stations being lighted. formance and compliance with the standard operating (4) At the transmitting station, place the signal requirements. test set controls as follows: NOTE (a) Test-Send key switch to Send Osc. Prior to performing this test, the circuit shall (b) Meter circuit selector % Break Direct. be aligned and conditioned to the required (c) Receive selector to any position except Send circuit characteristics and transmission levels and Rec. specified in the TSO. 6-18 TM 11-5895-1012-10 Figure 6-15. Phase jitter testing using a phase jitter meter. 6-19 TM 11-5895-1012-10 (d) Send selector to E&M line (M = B&G). (e) Send PPS selector to 10. (f) Function selector to Send Off Hook for calibrating and Send & Rec for sending. (5) At the receiving station, place the signal test set controls as follows: (a) Meter Circuit to % Break Direct. (b) Receive selector to G&O(E). (c) Function selector to CAL MTR for calibrating and Send & Rec for measuring. (6) The receiving station will calibrate the % break meter for 0% with the transmitting station in the off hook condition (Function selector to OFF HOOK). (7) If SF signaling is being tested, the transmitting station will send continuous pulse streams as follows: % Break Pulse Rate 47 10 PPS 67 10 PPS 47 12 PPS 12 PPS (8) If DX signaling is being tested, the transmitting station will send continuous pulse streams as follows: % Break Pulse Rate 8 PPS 54 8 PPS 62 12 PPS 54 12 PPS (9) The receiving station will measure the percent breaks of the received pulses. d. Performance Standards. For SF signaling the percentage breaks recorded at the receiving station will be 57 ± 10%, irrespective of the pulse rate used. For DX signaling the breaks recorded at the receiving station will be 58 the pulse rate used. 6-18. In-Station Signaling a Purpose This test determines operational signaling capability. b. Test Equipment. The following test equipment is required to perform this test: (1) Signal Test Set. (2) Signal Unit. (3) Circuit Termination Panel. (4) Terminating plug (600 ohms) and patch cords. c. Test Procedure. To test the receive line of a circuit, prepare the circuit shown in figure 6-17 and perIf a 4 wire circuit is to transmit lines. If FM on a separate pair, then connect the lead from the MISC PATCH panel to the voice circuit on the of the primary patch panel. signal test set as follows: (1) (a) Send PPS selector to ON (10 PPS). (b) TWD-L, LINE (E) selector to Off-Hook. 6-20 (c) Function selector to Test L&D. (2) Switch the TWD-L, LINE (E) selector to the ON HOOK position. The circuit termination panel should ring. (3) Switch the MISC PATCH lead from the REC to the XMIT line and terminate the REC line with a termination plug. Send a ring out from the circuit termination panel. The LINE (E) lamp should light. 6-19. Net Loss Variation Test (fig. 6-18) a. Purpose. This test will measure maximum net loss variation between stations or within a station and determine circuit compliance with the standard operating requirement. b. Test Equipment. The following test equipment is required to perform this test: (1) Transmission Test Set. (2) Noise Measuring Test Set. (3) Dual-Channel Recorder. (4) Termination plugs (600 ohms) and patch cords c. Station-to-Station Test. Contact distant station and arrange for one station to act as transmitter and one as receiver. Perform the procedure below and them reverse roles and repeat the procedure. (1) Transmitting Circuit. If the local station is to act as transmit&, prepare the transmitting circuit in figure 6-18 and set the transmission test set as follows: (a) Patch panel output impedance selector to 600 ohms. (b) Frequency selector to less than S KHz. (c) Turn on voltmeter. (2) Receiving Circuit. If the local station is to act as receiver, prepare the receiving circuit shown in figure 6-18 and set the noise measuring test set as follows: (a) Filter selector at Hi Pass. (b) Input at 600 ohms. (c) Sensitivity selectors initially at 0 dbm. (d) On the recorder, place the chart speed selector to one inch per minute and the range selector to 1 volt. (3) Procedure. (a) The transmitting station will calibrate the transmission test set for a 1000 Hz at - 10 dbm0 output signal. (b) Using only the servo pm drive corresponding to the upper module, the receiving station will calibrate the recorder to zero the servo pin in the center of the chart. (c) The receiving station will record the level of the 1000 Hz signal for a period of 15 minutes between 0800Z and 1200Z hours and for a period of 15 minutes between 2000Z and 2400Z hours. During this time, the transmitting station will vary the output of the transmission test set in 1 db steps, and the receiving station TM 11-5895-1012-10 Figure 6-16. Station to station signaling teat. 6-21 TM 11-5895-1012-10 Figure 6-17. In-station signaling test. will verify that the level meter changes in 1 db steps d. In-Station Test. In-station testing is acand the strip chart recorder shifts the distance in steps complished in the same manner as station to station testing except the local station acts as both transStandard. The maximum mitter and receiver. is ± 4db. Figure 6-18. Net loss variation test. 6-22 TM 11-5895-1012-10 6-20. Total Peak and Average Bias Telegraph Distortion Test (e) INPUT SELECT SWITCH to BRIDGING H1Z. WARNING DANGEROUS VOLTAGES are present during the preparation of the test circuits specified in figures 6-19 and 6-20. Turn all power switches off before constructing these test circuits. Failure to observe safety precautions could result in serious injury or death. c. Station-to-Station Test. Contact distant station and arrange for one station to act as transmitter and as a receiver. Perform the procedure below and then reverse roles and repeat the procedure. (1) Transmitting Circuit. If the local station is to act as transmitter, prepare the transmitting circuit shown in figure 6-19 and set the AN/GGM-15(V)1 test pattern generator controls as follows: (a) Use DATAOUTPUT. (b) P-N switch to P. (c) DISTORTION SELECT to NO DIST. (d) LEVEL CODE to 5. (e) CHARACTER LENGTH to 7. (f) MESSAGE SELECT to MSG. (g) BAUD RATE to 75. (2) Receiving Circuit. If the local station is to act as receiver, prepare the receiving circuit shown in fig- (f) BAUD RATESELECTOR to 75. (g) DISTORTION SELECT to TOTAL PEAK. (h) TRANSITION SELECT to ALL. (i) ALARM switch to RESET. (3) Procedure. (a) Turn on the power. If the distant station distortion analyzer signal lamp does not light, reverse the polarity switch. At the transmitting station, transmit the message "Quick Brown Fox". (b) At the receiving station, read the total peak distortion in percent and record it. The place the distortion analyzer ALARM switch to RESET and the DISTORTION SELECTOR to AVERAGE S/M. (c) At the transmitting station, transmit the message "Quick Brown Fox". The receiving station will mad the average displacement of the mark-to-space transitions of the input signal as indicated on the percent distortion meter. If the mark indicator lamp is on, marking bias distortion is indicated. If the space indicator lamp is on, spacing bias distortion is indicated. Record the results. (d) Turn power off at both stations. (4) Performance Standards. The maximum total peak telegraph distortion permissable is 20%. The maximum mark or space bias distortion permissable is 12%. Figure 6-19. Station to station total peak and average bias telegraph teat. 6-23 TM 11-5895-1012-10 Figure 6-20. In-Station total peak and average bias telegraph test. 6-24 TM 11-5895-1012-10 APPENDIX A REFERENCES The following publications are available to personnel assigned to the Technical Control Facility: A Pam 310-4 Index of Technical Manuals, Technical Bulletins, Supply Manuals, (Types 7, 8, and 9), Supply Bulletins, and Lubrication Orders. A Pam 310-7 US Army Equipment Index of Modification Work Orders. CAC 310-70-1 Volume I, DCS Technical Control Policy and Facilities; Volume II, DCS Technical Control Procedures; Volume IV, DCS Technical Control Glossary. ECEO H500-12-64 DCS Technical Control Engineering Criteria. Subsystems Design and Engineering Standards for Technical Control Facilities. IL-STD-188-310 Reservation, Packaging, Packing, and Marking Materials, Supplies and Equipment Used B 38-100 by the Army. B 43-0118 Field Instructions for Painting and Preserving Electronics Command Equipment Including Camouflage Pattern Painting of Electrical Equipment Shelters. M 38-750 The Army Maintenance Management Systems (TAMMS). A-1 TM 11-5895-1012-10 APPENDIX B ABBREVIATIONS B-1 TM 11-5895-1012-10 B-2 TM 11-5895-1012 INDEX Abbreviations Administrative storage Circuit performance Excessive signal levels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Improper terminations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .......................................................... Introduction Performance monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Quality control Government-owned circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...................................................... Leased circuits Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Schedules ............................................... . ............................................ Tests Trend analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Circuit rerouting Catastrophic failure procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Emergency procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Normal procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Circuit test procedures (Quality and maintenance) Audio frequency. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Composite signal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .......................................... Envelope delay distortion. ......................................... Frequency response Harmonic distortion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Idle channel noise. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Impulse noise ........................................ Longitudinal balance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Net loss variation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Phase jitter Using oscilloscope Using phase jitter meter Signaling test In-station Station-to-station Single tone interference Telegraph bias distortion Terminal impedance Receive circuit transmit circuit Test conditions Paragraph 1-7. , 1-4. , Page 1-1 1-1 4-52. 4-53. 4-46. 4-50. 4-44 4-45 4-39 4-43 4-47. 4-48. 4-54. 4-49. 4-55. 4-51. 4-40 4-40 4-45 4-40 4-45 4-43 4-16. 4-15. 4-13. 4-14. , , , , 4-6 4-5 4-4 4-4 6-7. , 6-6 6-14. , 6-15 6-6. , 6-3 6-5. , 6-2 6-13. , 6-14 6-4. , 6-2 6-10. , 6-8 6-8. , 6-6 6-19. , 6-20 6-15. 6-16. , , 6-15 6-17 6-18. 6-17. 6-9. 6-20. , , , , 6-20 6-18 6-8 6-23 6-12. 6-11. 6-3. , , , 6-12 6-12 6-2 Destruction Distribution frames 1-5. 2-22. , , 1-1 2-27 EIR reporting Examples of operating TCF's Berlin 1-6. , 1-1 3-4. 3-6. 3-7. 3-15. 3-1. 3-3. , 3-4 , , , 3-6 3-12 3-1 4-23. 4-37. , , Pentagon Pirmasens Fault isolation Circuit outages Circuit status 4-12 4-30 Index 1 TM 11-5895-1012-10 Page Paragraph Commercial outages. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Example procedures Dc circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Voice channel ............. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Faults Baseband . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Dc . . . . . . . . . . . . . . . . ................ ................................ Multichannel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Single VF channel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Responsibilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Restoration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . TCF functional areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Troubleshooting practices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Voice frequency isolation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Forms and records . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Implementation of CSR's Procedures . ................................ . . . . . . . . . . . . . . . . Sample circuit ................ . .. . . . . . . . . .... TCF responsibilities .. .. ... . . . . . . . . . . . . . . . TSO's .. ................ Index of publications . . . . . . . . . . . . . . . . Installed facilities (See TCF facilities) 4-34. 4-20 4-36. 4-35. 4-27 4-20 4-32. 4-33. 4-31. 4-30. 4-22. 4-28. 4-25. 4-38. 4-26. 4-27. 4-29. 1-3. 4-18 4-19 4-18 4-17 4-12 4-12 4-15 4-30 4-16 4-16 4-17 1-1 4-58. 4-59. 4-57. 4-56. 1-2. 4-47 4-47 4-46 4-46 1-1 Maintenance tests (See circuit testing procedures) New equipment acceptance General TCF responsibilities Test and acceptance Operation practices and methods On-call circuits Orderwires Discipline Procedure Types Service interruptions Correction of hazardous conditions Emergency Scheduled .. Station management ......... . Approach. . . . . . . . . . . . . Facilities and usage System management Technical controller duties TELECON circuits .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..... . . . . . . . . . . . . . . . . 4-60. 4-61. 4-62. , , , 4-49 4-49 4-49 . . . . . . . . . . . . . . . . . 4-9. , 4-3 . . . . . . . . . . . . . . . . ...... ................ ..... . . . . . . . . . . . . . . . . 4-7. 4-6. 4-5. , , , 4-3 4-2 4-2 ................ .... . . . . . . . . . . . . . . . . ................ 4-12. 4-11. 4-10. , , , 4-4 4-4 4-3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .... ................ ................ ................ ................ . . . . . . . . . . . . . . . . .. 4-2. 4-3. 4-1. 4-4. 4-8. , , , , , 4-1 4-1 4-1 4-2 4-3 , , , , , 4-7 4-6 4-5 4-6 4-6 , , , , , , 4-39 4-37 4-31 4-39 4-31 4-37 4-39 , 2-33 Patching 4-21. Dc facilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-18. Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Purpose . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-17. 4-19. Reporting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-20. VF facilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . Performance standards 4-43. Conduct of tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-42. Digital distortion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . General 4-39. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-45. Recording test results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-40. Technical schedules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Test descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-41. . . . . . . . . . . . . . . . . 4-44. Test reporting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2-23. Power facilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-29. Index 2 TM 11-5895-1012-10 Paragraph Page QC test (see Circuit testing procedures) Quality control testing (See circuit performance) Representative TCF equipment Circuit conditioning . . . . . .. . . . . .. . . . . .. . . . . .. . . . . .. . . . . . . . . . . . . . . . . . DLIU . . . . . .. . . . . .. . . . . .. . . . . . General . . . . . .. . . . . .. . . . . .. . . . . . Other conditioning equipment. . . . . . . . . . . . . . . . . . . . . . . .. . . . . . Patch panels Dc . . . . . . . . . . . . . . . . . . . . . . . ...... Miscellaneous . . . . . . . . . . . . . . . . . . . . . . . . VF and E&M . . . . . .. . . . . .. . . . . . . . . . . . . . . . . . . . . . . . Signaling . . . . . . . . . . . . . . . . . . . . . . . . Test equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rerouting (See circuit rerouting) ............ ............ Scope Signal facilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............ Station cabling . . . . . . . . . . . . Station maintenance Checks and services . . . . . . . . . . . . Daily . . . . . . . . . . . . . . . . . . . . . . . . Periods . . . . . . . . . . . . . . . . . . . . . . . . Quarterly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Weekly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............ Prevention maintenance . . . . . . . . . . . . . . . . . . . . . . . . System service interfaces AUTODIN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . AUTOVON . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Common user network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Communications facilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Relay centers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............ ............ Transmission media . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............ TCF function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . TCF interfaces Ac power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Classes of power . . . . . . . . . . . . . . . . . . . . . . . . ........................ Configuration . . . . . . . . . . . . . . . . . . . . . . . . Digital data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............ Distribution frames . . . . . . . . . . . . . . . . . . . . . . . . ............ Generating equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Internal . . . . . . . . . . . . . . . . . . . . . . . . .. ............ . . . . . . . . . . . . Miscellaneous . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Power. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Power distribution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... . . . . . . . . . . . . Stating cabling . . . . . . . . . . . . ... Uninterruptible power supply (UPS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............ . . ............ Voice frequency . . . . . . . . . . . . Wideband . . . . . . . . . . . . . . . . . . . . . . . . ... . ............ . . . . . . . . . TCF purpose . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...... TCF responsibilities. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. ..... ...... TCF signals. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Technical control facility Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ........................ Purpose . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Responsibilities Additional ............ ..... . . . . . . . . . . . . General 2-31. 2-39. 2-30. 2-33. , , , , 2-36 2-54 2-34 2-37 2-36. 2-37. 2-35. 2-34. 2-33. , , , , , 2-38 2-45 2-33 2-37 2-50 1-1. 2-17. 2-18. 2-19. 2-20. 2-21. , , , , , , 1-1 2-15 2-24 2-24 2-26 2-27 6-3. , 5-1 5-2. , 5-1 5-5. , 5-2 5-4. , 5-1 5-6. , 5-2 5-1. , 5-1 2-13. 2-12. 2-8. 2-10. 2-7. 2-11. 2-9. , , , , , , , 2-9 2-8 2-4 2-6 2-4 2-8 2-4 2-2. , 2-1 2-25. 2-24. 2-16. 2-18. 2-22. 2-26. 2-20. 2-29. 2-23. 2-27. 2-21. 2-28. 2-17. 2-19. 2-1. 2-3. 2-6. 2-14. , , , , , , , , , , , , , , , 2-28 2-23 2-12 2-24 2-27 2-28 2-26 2-33 2-27 2-29 2-27 2-30 2-15 2-24 2-1 , , 2-3 2-11 2-2. 2-15. 2-1. , , , 2-1 2-11 2-1 2-5. 2-3. , 2-2 2-1 Index 3 TM 11-5895-1012-10 To subscribers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Special assignments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Technical controllers duties. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Test equipment description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Test procedure introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Test procedures (see circuit testing procedures) Paragraph Page 2-4. 2-6. 4-4. 6-2. 6-1. 2-2 2-3 4-2 6-1 6-1 , , , *US GOVERNMENT PRINTING OFFICER 1978-703-128558 Index 4 TM 11-5895-1012-10 BERNARD W. ROGERS General, United States Army Chief of Stuff Official: B J.C. PENNINGTON r General, United States Army The Adjutant General (1) USACC (1) Armies (1) HISA (Ft Monmouth) (33) Ft Huachuca (2) Ft Richardson (ECOM Ofc) (1) *Ft Carson (2) Ft Gillem (2) USASIGS (10) Svc Colleges (l) USAERDAA (1) USAERDAW (1) Sig FLDMS (1) ARNG & USAR: None. For explanation of abbreviations used, see AR310-50. Figure FO-1. Simplified power distribution diagram. Figure FO-2. Vf primary or equal level patch panel, interconnection diagram Figure FO 2 Vf primary or equal level patch panel, interconnection diagram TM 11-5895-1012-10 Figure FO-3. Primary dc patch panel, interconnection diagram. TM 11-5895-1012-10 Figure FO-4. Dc patch panel (receive) with cut keys and lamps, interconnection diagram TM 11-5895-1012-10 Figure FO-5. Dc patch panel (transmit) with cut keys and lamps, interconnection diagram TM 11-5895-1012-10 Figure FO-6. TCF, Pirmasens, signal diagram TM 11-5895-1012-10 Figure FO-7. TCF, Pirmasens, floor plan. TM 11-5895-1012-10 Figure FO-8. TCF, Berlin, signal diagram. TM 11-5895-1012-10 Figure FO-9. TCF, Berlin, floor plan TM 11-5895-1012-10 Figure FO-10. TCF, Pentagon, signal diagram. Figure FO-11. TCF, Pentagon, floor plan. TM 11-5895-1012-10 Figure FO-12. TCF, Pentagon, floor plan. Figure FO-13. Typical black digital circuit IDF connection diagram TM 11-5895-1012-10 Figure FO 13. Typical black digital circuit IDF connection diagram TM 11-5895-1012-10 Figure FO-14. Universal digital patch panel, interconnection diagram. TM 11-5895-1012-10 Figure FO-15. Universal digital patch panel black send circuit strapping diagram TM 11-5895-1012-10 Figure FO-16. Universal digital patch panel black receive circuit strapping diagram This fine document... Was brought to you by me: Liberated Manuals -- free army and government manuals Why do I do it? I am tired of sleazy CD-ROM sellers, who take publicly available information, slap “watermarks” and other junk on it, and sell it. Those masters of search engine manipulation make sure that their sites that sell free information, come up first in search engines. They did not create it... They did not even scan it... Why should they get your money? Why are not letting you give those free manuals to your friends? I am setting this document FREE. This document was made by the US Government and is NOT protected by Copyright. Feel free to share, republish, sell and so on. I am not asking you for donations, fees or handouts. If you can, please provide a link to liberatedmanuals.com, so that free manuals come up first in search engines: <A HREF=http://www.liberatedmanuals.com/>Free Military and Government Manuals</A> – Sincerely Igor Chudov http://igor.chudov.com/ – Chicago Machinery Movers
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