QRSS - TE Connectivity
ADCP-61-027 • Issue 5 • July 2000
Q1544-20 and Q1544-21)
Quasi-Random Signal Source (QRSS)
User Manual)
13830-A
Content
Page
INTRODUCTION .......................................................................... 2
Revision History ..................................................................... 2
Trademark Information ................................................................ 2
Admonishments ..................................................................... 3
1088958 Rev A
1
PRODUCT DESCRIPTION ............................................................... 3
2
SPECIFICATIONS..................................................................... 5
3
INSTALLATION ...................................................................... 6
4
OPERATION ........................................................................ 6
5
CUSTOMER INFORMATION AND ASSISTANCE ................................................. 7
Page 1
© 2000, ADC Telecommunications, Inc.
ADCP-61-027 • Issue 5 • July 2000
INTRODUCTION
This manual provides the description and operation of ADC’s Model Q1544-20 T1 QuasiRandom Signal Source (QRSS) Common Module (provides 10 QRSS outputs), and the
optional T1 QRSS Output Module, Model Q1544-21 (provides 20 QRSS outputs). The
common module may control either one or two optional output modules.
The QRSS common module and optional output module are plug-in printed circuit cards,
attached to a front panel, that mount in an ADC QRSS/Bridging Repeater Mounting Shelf,
Model M1544-100. The front panel also has a pull-out handle plus Bell’s common language
equipment identification (CLEI) code and bar code label.
ADC PCM equipment is identified by a model and part number on the front panel or located
elsewhere on the equipment.
The T1 (1.544 Mb/s) Quasi-Random Signal Source performs the following functions:
1. Provides a controlled error-free test signal used during troubleshooting.
2. Provides a far-end office with a standard signal source for bit error-rate measurements.
3. Provides testing signals for spans thought to be marginal.
4. Drives unassigned lines.
5. Drives idle lines during system turn-up or span line rearrangements.
6. Drives maintenance and backbone lines.
Two QRSS common modules and four output modules can be mounted in ADC’s Model
M1544-100 QRSS/Bridging Repeater Mounting Shelf. Altogether, they provide a total of 100
QRSS outputs. The QRSS/Bridging Repeater Mounting Shelf also provides eight (8)
mounting slots for bridging repeaters.
One QRSS common module and one output module can be mounted in ADC’s Model M1544310 QRSS/Bridging Repeater Mounting Shelf. Altogether, they provide a total of 30 QRSS
outputs. The QRSS/Bridging Repeater Mounting Shelf also provides two (2) mounting slots
for bridging repeaters.
Revision History
ISSUE
DATE
REASON FOR CHANGE
Issue 4
10/1991
Reissued to add caution to Installation section.
Issue 5
07/2000
Update to current format standards.
Trademark Information
ADC and ADC Telecommunications are registered trademarks of ADC Telecommunications, Inc.
Common Language is a registered trademark and CLEI, CLLI, CLFI, and CLCI are trademarks of
Bell Communications Research, Inc.
Page 2
© 2000, ADC Telecommunications, Inc.
ADCP-61-027 • Issue 5 • July 2000
Admonishments
Important safety admonishments are used throughout this manual to warn of possible hazards
to persons or equipment. An admonishment identifies a possible hazard and then explains
what may happen if the hazard is not avoided. The admonishments — in the form of Dangers,
Warnings, and Cautions — must be followed at all times. These warnings are flagged by use
of the triangular alert icon (seen below), and are listed in descending order of severity of
injury or damage and likelihood of occurrence.
Danger: Danger is used to indicate the presence of a hazard that will cause severe personal
injury, death, or substantial property damage if the hazard is not avoided.
Warning: Warning is used to indicate the presence of a hazard that can cause severe
personal injury, death, or substantial property damage if the hazard is not avoided.
Caution: Caution is used to indicate the presence of a hazard that will or can cause minor
personal injury or property damage if the hazard is not avoided.
1
PRODUCT DESCRIPTION
The QRSS common module (block diagram shown in Figure 1) generates a basic quasi-random
word (QRW) signal. The generated QRW is 1,048,575 bits in length and is limited to 14 successive
zeros. This is the Bell System standard signal and because the QRW incorporates a full range of
mark/space combinations, it is used to simulate the energy spectrum of a T1 carrier line.
T1 CLOCK
CLOCK
CIRCUITRY
RAIL 2
DOUBLE RAIL
CONVERTER
FAST CLOCK
RAIL 1
TO OUTPUT MODULE
15 ZERO
DETECTOR
20 BIT SHIFT
REGISTER
PATTERN
LOGIC
QRW
T1
BIPOLAR OUTPUTS
OUTPUT
DRIVERS
OUTPUT SHIFTING
RAIL 1
FEEDBACK
LOGIC
20 ZERO
DETECTOR
OUTPUT SHIFTING
RAIL 2
RAIL 1 TO OUTPUT MODULE
RAIL 2 TO OUTPUT MODULE
–5
VOLTS
–48 VOLTS IN
GND IN
POWER
CONVERTER
GND
TO ALARM
RELAY CONTACTS
ALARM
CIRCUITRY
OUTPUT
MODULE 1 ALARM
OUTPUT
MODULE 2 ALARM
FAIL
LAMP
13820-A
BOR ALARMS
Figure 1. Common Module Block Diagram
Page 3
© 2000, ADC Telecommunications, Inc.
ADCP-61-027 • Issue 5 • July 2000
The common module provides ten (10) outputs via wire-wrapped terminals at the rear of the
mounting shelf. It also provides the signal bit data to the first optional output module. The –48
Vdc office battery power is fed through a 0.5 A GMT alarm type fuse, on the common
module, into a –48 to –5 Vdc converter. Most of the common module circuitry is powered
from the -5 Vdc supply. The analog portion of the alarm circuitry for both modules is powered
from the –48 Vdc office battery. The two optional output modules associated with the
common module are also powered from the common module. The –48 Vdc office battery
input is connected to a terminal block on the rear of the mounting shelf.
The common module LED and its alarm relay contacts provide the essential alarm functions.
The LED is illuminated and the alarm relay releases under the following conditions:
1. Front panel fuse operates.
2. Loss of internal –5 Vdc supply.
3. Faulty PCM bit stream.
The common module alarm relay only (LED is not illuminated) releases under the following
conditions:
1. Input (-48 Vdc) office battery fails.
2. Alarm signal from either optional output module.
3. Bridging repeater alarm.
Note: The ADC M1544-100 also provides mounting slots for eight ADC bridging repeaters.
The alarm relay, in the normal position (operated), furnishes a dry contact alarm interface
with “Normally Open” (NO) or “Normally Closed” (NC) contacts for alarm leads. These
alarm lead terminals appear on a terminal block, at the rear of the mounting shelf, for
connection to a local alarm system. One of the two optional output modules controlled by a
common module is depicted in Figure 2. Each output module provides 20 QRSS outputs.
Altogether, a total of 50 QRSS outputs are provided via wire-wrapped terminals at the rear of the
mounting shelf, per common module group.
FAST CLOCK
RAIL 1 INPUT
OUTPUT SHIFTING
RAIL 1
RAIL 2 INPUT
OUTPUT SHIFTING
RAIL 2
BIPOLAR
OUTPUT
DRIVERS
T1 OUTPUTS
RAIL 1 (BIT FOLLOWING 20TH OUTPUT)
RAIL 2 (BIT FOLLOWING 20TH OUTPUT)
ALARM
CIRCUITRY
TO COMMON
MODULE
ALARM/RELAY
GND IN
–5 VOLTS IN
–48 VOLTS IN
TO ALARM
FAIL
LAMP
13821-A
Figure 2. Output Module Block Diagram
Page 4
© 2000, ADC Telecommunications, Inc.
ADCP-61-027 • Issue 5 • July 2000
The first output module receives its signal bit data from the output of the common module and
the second output module receives its signal bit data from the first output module. The output
modules are powered by the –5 Vdc supply from the common module and the alarm circuit is
powered from –48 Vdc battery.
The alarm circuitry is the same as in the common module except that the output module alarm
signal is sent back to the common module alarm relay. The output module LED is illuminated
and an alarm signal occurs under the following conditions:
1. Loss of the –5 Vdc.
2. Faulty PCM bit stream.
2
SPECIFICATIONS
The Common and Output Modules specifications are listed in Table 1.
Table 1. Specifications
PARAMETER
SPECIFICATION
Outputs
Output Signal
QRW Format
T I Pulse Format
Pulse Width
Pulse Width Unbalance
Rise/Fall Times
Pulse Amplitude
Pulse Amplitude Unbalance
Baseline Overshoot
Meets Bell DSX-1 Interconnect Specification (CB-119).
1,048,575 bit sequence generated by a 20-bit shift register with
bits 17 and 20 fed back and limited to 14 successive zeros.
Rate of 1. 544 Mbps ± 80 bps bipolar alternate mark inversion;
50% duty cycle.
Note: Output parameters apply to T1 outputs with a nominal
load of 100 ohms.
324 nsec ± 30 nsec (measured from 50% crossing of rising edge
to 50% crossing of falling edge of pulse).
Positive and negative pulse width within –15 nsec of each other.
60 nsec maximum.
3 Volts ± 0.3 Volts at midpoint.
Positive and negative pulse amplitude within .15 Volts of each
other.
10% to 30% of pulse amplitude.
Environmental
Supply Voltage
Supply Current:
Common Module Alone
Common Module + 1 Output Module
Common Module + 2 Output Modules
Fuse
Operating Ambient Temperature
Storage Ambient Temperature
Operating Relative Humidity
Storage Relative Humidity
–42 to –56 Vdc.
150 mA.
225 mA.
300 mA.
1/2 Ampere.
O°C to +50°C ( +32°F to +122°F).
–40°C to +70°C (–40°F to +158°F).
Meets NEBS requirements (no condensation).
5 to 95% (no condensation).
Physical Description
Dimensions:
Common Module: 10. 1 × 3.7 × 0. 6 inches (25.7 × 9.4 × 1. 5 cm)
Output Module: 10.1 × 3.7 × 0.6 inches (25.7 × 9.4 × 1.5 cm)
Page 5
© 2000, ADC Telecommunications, Inc.
ADCP-61-027 • Issue 5 • July 2000
3
INSTALLATION
Warning: Never install telephone equipment in a wet location or during a lightning storm.
When installing or modifying telephone lines, disconnect lines at the network interface before
working with uninsulated lines or terminals.
The optional QRSS output modules mount in positions ten (10), eleven (11), thirteen (13), and
fourteen (14). The output modules in positions 10 and 13 are driven by the common modules
in positions 9 and 12 respectively. The output modules in positions 11 and 14 are driven by
the output modules in positions 10 and 13 respectively
Other QRSS applications may only require a common module (10 outputs), or a common
module and output module (30 outputs).
To install the common and output modules, proceed as follows. Slide the keyed card into
place in the mounting position and make sure it is firmly seated. Electrical, circuit and alarm
connections are established by plug-in contacts at the rear of the printed circuit card. Channel
guides assure proper alignment of the card and positive connections of the contacts. If there is
excessive resistance, remove the module and check for improper alignment or obstructions.
Terminate all unused QRSS outputs with 100 ohm 1/4 watt resistors. This may be
accomplished by wiring 100 ohm resistors to the QRSS output jacks using ADC’s Resistor
Panel Assembly, Part Number 4-26232-0010 (see Figure 3 for the wiring diagram). The
Resistor Panel Assembly provides fifty 1/4 watt 100 ohm resistors secured to wire-wrap
terminal block pins and mounted on a 19-inch panel suitable for relay rack installation.
Another method of terminating the unused QRSS output jacks is by inserting 100 ohm plugs
in the output jacks.
RES.PNL.
DSX-1
MISC. JACKFIELD
A
100Ω
B
QRSS
OUTPUT
T
T
R
R
S
13822-A
Figure 3. Resistance Panel Wiring Diagram
4 OPERATION
There are no operating instructions to initiate the operation of the common and output
modules. The modules are operational as soon as they are installed in the mounting shelf and
power is applied.
Page 6
© 2000, ADC Telecommunications, Inc.
ADCP-61-027 • Issue 5 • July 2000
5
CUSTOMER INFORMATION AND ASSISTANCE
For customers wanting information on ADC products or help in using them, ADC offers the
services listed below. To obtain any of these services by telephone, first dial the central ADC
telephone number, then dial the extension provided below.
The central number for calls originating in the U.S.A. or Canada is 1-800-366-3891. For calls
originating outside the U.S.A. or Canada, dial country code “1” then dial 612-946-3000.
Sales Assistance
Extension 3000
• Quotation Proposals
• Ordering and Delivery
• General Product Information
Systems Integration
Extension 3000
•
•
•
•
•
•
•
Complete Solutions (from Concept to Installation)
Network Design and Integration Testing
System Turn-Up and Testing
Network Monitoring (Upstream or Downstream)
Power Monitoring and Remote Surveillance
Service/Maintenance Agreements
Systems Operation
BCG Technical Assistance Center
Extension 3475
E-Mail: technical@adc.com
•
•
•
•
•
•
Technical Information
System/Network Configuration
Product Specification and Application
Training (Product-Specific)
Installation and Operation Assistance
Troubleshooting and Repair
Product Return Department
Extension 3748
E-Mail: repair&return@adc.com
• ADC Return Authorization number and instructions must
be obtained before returning products.
Product information may also be obtained using the ADC web site at www.adc.com or by
writing ADC Telecommunications, Inc., P.O. Box 1101, Minneapolis, MN 55440-1101, U.S.A.
Contents herein are current as of the date of publication. ADC reserves the right to change the contents without prior notice. In
no event shall ADC be liable for any damages resulting from loss of data, loss of use, or loss of profits and ADC further
disclaims any and all liability for indirect, incidental, special, consequential or other similar damages. This disclaimer of
liability applies to all products, publications and services during and after the warranty period.
This publication may be verified at any time by contacting ADC’s Technical Assistance Center at 1-800-366-3891, extension
3475 (in U.S.A. or Canada) or 612-946-3000 (outside U.S.A. and Canada), or by writing to ADC Telecommunications, Inc.,
Attn: Technical Assistance Center, Mail Station #71, P.O. Box 1101, Minneapolis, MN 55440-1101, U.S.A.
© 2000, ADC Telecommunications, Inc.
All Rights Reserved
Printed in U.S.A.
Page 7
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