Installing The Loop Start Line Board

In The DXP Plus Digital Communications System

1.0 Introducing The Loop Start Line Board

1.1

Defining Loop Start

The line board signals for the host system to complete a line connection by sending a supervisory signal to the host system. Typically this signal is the hookflash that occurs when a user takes a telephone off hook on the line.

The line board transmits this signal to the host system by placing a resistance across the line’s tip and ring leads to complete a current loop. When the host system senses this resistance, it sends dial tone over the line thus giving line service to the system.

1.2

Inventorying The Loop Start Line Boards

There are two versions of the loop start line board. One version interfaces four central office lines and the other version interfaces eight central office lines.

1.3

Complying With Underwriters Laboratories Regulations

Per The Underwriters Laboratories regulation 1459, 2nd edition, be aware of the following precautions when installing telephone equipment that is to be directly connected to the telephone company network:

•

Never install telephone wiring during a lightning storm.

•

Never install telephone jacks in wet locations unless the jack is specifically designed for wet locations.

•

Never touch un-insulated telephone wires or terminals unless the telephone line has been disconnected at the network interface.

•

Use caution when installing or modifying telephone lines.

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This manual has been developed by Comdial Corporation (the “Company”) and is intended for the use of its customers and service personnel. The information in this manual is subject to change without notice.

While every effort has been made to eliminate errors, the Company disclaims liability for any difficulties arising from the interpretation of the information contained herein.

The information contained herein does not purport to cover all details or variations in equipment nor to provide for every possible contingency to be met in connection with installation, operation, or maintenance.

Should further information be desired, or should particular problems arise which are not covered sufficiently for the purchaser’s purposes, contact Comdial, Inside Sales Department, Charlottesville, Virginia

22906.

Printed in U.S.A.

IMI89-172.01

7/95

IMI89–172 Installing The Loop Start Line Board

2.0 Installing Circuit Boards In The Equipment Cabinet

CAUTION

Circuit boards are susceptible to damage caused by electrostatic discharge, and you must keep this fact in mind as you handle the circuit boards.

Refer to the Comdial publication IMI01-005, Handling Of

Electrostatically Sensitive Components, for general information. Specific handling precautions are also included in this installation instruction.

2.1

Creating A Static Safe Work Area

When servicing the common equipment cabinet at the installation location, it is a good practice to place a conductive mat in front of the cabinet area and ground the mat to a good earth ground. (The third wire ground of the AC power line is also an acceptable grounding point.) The grounded conductive mat provides a safe static electric discharge path.

When removing the common equipment cabinet from the installation location for servicing, it is a good practice to prepare a static-safe work area on which to place the cabinet.

You should supply yourself with a static discharge wrist strap, and wear it every time you handle electronic circuit boards either at the cabinet mounting location or at your work area.

2 – Installing The Loop Start Line Board

Installing The Loop Start Line Board IMI89–172

PLUS035

Expansion

Cabinet

Common

Equipment

Cabinet

Static Discharge

Wrist Stap

Expansion

Cabinet

Conductive

Mat

1 Meg Ohm

Resister

Earth

Ground

Providing Static Protection At The Cabinet Mounting Location

Static

Wrist

Strap

Common Point Ground

ESD Protective

Mat

ESD Protective

Worksurface

Typical Earth

Ground

Static 2

ESD Protective

Mat

Creating A Static Safe Work Area

Installing The Loop Start Line Board – 3

IMI89–172 Installing The Loop Start Line Board

2.2

Installing Loop Start Line Boards

1. Normally you should disconnect the AC power cord from the AC outlet and disconnect the optional battery back-up assembly from the main cabinet power supply; however, when necessary, you can install a line board in an operating system. If you must do this, connect one end of a standard telephone handset coil cord to the precharge port on the power supply. During step 5, you will connect the other end of this coil cord to the precharge jack on the line board.

2. Install your static discharge wrist strap on your bare wrist; adjust it for a snug fit. Be sure that the strap is touching bare skin and is not isolated by clothing. Connect the wrist strap cord between the wrist strap and an

AC or earth ground

NOTE: With the common equipment in the installed position, the ground lug on the side of the cabinet is an appropriate grounding point since it should have a heavy ground wire connected between it and a good earth ground.

3. Each circuit board is supplied in a static protection bag for safe keeping. When you are ready to install the circuit board, remove it from its static protection bag.

4. Locate the proper board slot.

•

On DXP Plus systems the loop start line boards connect to any universal slot.

NOTE: On DXP Plus systems, do not install a line board at the right-most board slot in the second (or lower) expansion cabinet. The system reserves this slot for internal use.

5. If you are installing the line board in an operating system, connect the free end of the precharge cord that you installed in step 1 to the precharge jack on the line board.

6. Orient the circuit board with its top and bottom guides in main cabinet board cage. and press the board firmly until its board edge connection properly mates with the connector on cabinet’s backplane.

CAUTION

When pressing circuit boards into place, press them only at the extractor lever locations.

If you apply pressure at other locations you may damage the board assembly.

7. Repeat steps 3 and 4 until all circuit boards are installed.

8. Make a final inspection to ensure that all circuit boards are, oriented correctly and mated properly.

9. Install and tighten the supplied screws to secure the circuit boards to the board cage.

10. Each line board includes a ferrite collar. Bundle the line cables together and snap the ferrite collar around the cable bundle to provide protection against radio frequency interference.

4 – Installing The Loop Start Line Board

Installing The Loop Start Line Board

PLUS032

Power Supply

Pre-charge Port

IMI89–172

Line Board

Pre-charge

Jack

Pre-charge Cable

For Line Board

Installation During

Power Up

Loop Start

Line Board

Static Discharge

Wrist Strap

Viewing A Typical Line Board Installation

Installing The Loop Start Line Board – 5

IMI89–172 Installing The Loop Start Line Board

3.0 Connecting The Telephone Lines

The line terminations on the line board are standard modular plug/jack connections. Each modular jack provides termination for two lines. The line outside termination can be a type 66M-xx connector block or individual

6-position modular jacks. The wiring that is routed between the outside termination and the common equipment circuit board termination should be twisted-pair wiring.

Remember, each line board is shipped with a ferrite collar. Bundle the line cables together and snap the collar around the bundle to provide protection against radio frequency interference.

Detailing The Line Board Connections

Line Jack

1

2

3

4

5

Pin Number

1

5

6

1

2

3

2

3

4

4

5

6

5

6

1

2

3

4

5

6

1

2

3

4

5

6

1

2

3

4

Connection

No Connection

Line 8 Tip

Line 7 Tip

Line 7 Ring

Line 8 Ring

No Connection

No Connection

Line 6 Tip

Line 5 Tip

Line 5 Ring

Line 6 Ring

No Connection

No Connection

Line 4 Tip

Line 3 Tip

Line 3 Ring

Line 4 Ring

No Connection

No Connection

Auxiliary (Line 2) Tip

Line 1 Tip

Line 1 Ring

Line 2 Ring

Auxiliary (Line 2) Ring

No Connection

No connection

Power Fail (Line 1) Ring

Power Fail (lIne1 ) Tip

No Connection

No Connection

Telephone Number

NOTE: If the system operation includes the direct inward station access (DISA) feature on a particular line, callers that use DISA to access a trunk group and place calls (trunk to trunk calling) may experience low audio levels on their calls due to the normal line resistance of CO lines. Low audio level is usually only noticeable on long line loops. If signal loss is a problem at your site, try adding a line amplifier (repeater) in the DISA line. Comdial does not recommend DISA for use on loop start lines without disconnect supervision. While DISA will function, Comdial will not be liable for its performance under any condition where disconnect supervision is not provided.

6 – Installing The Loop Start Line Board

Installing The Loop Start Line Board

PLUS033

IMI89–172

Ferrite

Collar

Viewing A Typical Line Connection

Connect Line

Cable to

Outside Line

Termination

Installing The Loop Start Line Board – 7

IMI89–172 Installing The Loop Start Line Board

3.1

Understanding The DXP Plus Logical Numbering

Because there are no dedicated station or line ports in the DXP Plus, the system uses an automatic configuration method to logically number its stations and lines. Automatic configuration occurs after you perform a master clear on the system.

How automatic configuration works

With automatic configuration, the system does a search for all installed station and line boards in the main and expansion cabinets, and assigns a logical number for each provided station and line encountered during the search.

The search begins in the main cabinet at the left-most universal slot and proceeds left to right. The search then moves to the upper expansion cabinet where it searches left-most slot to right-most slot. The search finally moves to the lower expansion cabinet where it again searches left-most slot to right-most slot. When automatic configuration is finished, the system has logically numbered all station and line ports in ascending order from the left-most slot to right-most slot throughout the entire system.

How logical number and physical location relate to one another

The logical number of a station or line corresponds to its relationship to other stations or lines in the system but is not dependent upon the board’s placement in the cabinet. The physical location of a station or line corresponds to the order of the system’s board slots. The main cabinet contains slots 1–9, the upper expansion cabinet contains slots 10–20, and the lower expansion cabinet contains slots 21–30. Therefore, even if the first encountered station board is located in slot five of the main cabinet, the system still assigns logical number one to the first station provided by that board. During installation, you can skip slots. For example, you can install eight-line, loop start, line boards in only slots one and 30 if you wish. In this case, slot one yields logical line numbers 1–8 and slot 30 yields logical line numbers 9–17.

Where you can place circuit boards

Each installed board requires timing circuits equal to its capacity. For example, a 16–station board requires 16 timing circuits, an eight–line loop start line board requires eight circuits, and a fully configured T1 trunk board requires 24 timing circuits. In the DXP Plus, each universal slot provides 32 timing circuits. Because of this timing circuit provision of each slot, you can place any station or line board at any slot location with no restrictions.

Adding boards without renumbering

If you install or relocate a station or line board, this board does not operate until you take appropriate programming action. If you use an available open slot for adding or relocating a board, that board’s stations or lines assume logical numbers in sequence after the system’s last assigned logical station or line number. For example, if the system’s last logical station number is 24, the logical numbers of the newly installed board’s stations begin at logical number 25.

After you remove a board and delete it through programming, that board’s logical numbers are available for reassignment. This means that you can remove a board, add or move another board, take the appropriate programming action, and have the stations or lines of the added or relocated board assume the logical numbers made available by the removed board. For example, if the system’s last logical number is 64 and you remove the board providing stations with logical numbers 1–16 and delete it through programming, the stations on an added board assume logical numbers beginning with 1 instead of 65. However, if you remove and program delete an eight-station board and add a 16-station board, the first eight stations stations on the added board assume logical numbers 1–8 and the last eight stations assume logical numbers 65–72.

Remember, should you master clear the system, the automatic configuration feature logically numbers all station and line ports in ascending order from the left-most slot to right-most slot throughout the entire system. This action renumbers those station and lines provided by boards that you have added or relocated since you last performed the system master clear.

8 – Installing The Loop Start Line Board

Installing The Loop Start Line Board IMI89–172

4.0 Making A Power Failure Station Connection

Every loop start line board provides a tip and ring pair connected to line 1 as an emergency power failure circuit.

This power fail circuit is active during a commercial AC power failure if an external battery assembly is not installed to provide battery back-up power to the system. Connect an industry standard, single-line telephone to the power failure jack and use it to provide basic communications capability until the AC power to the system is restored. The bottom jack on the line board provides the power failure connection.

PLUS065

Line Board

4

3

6

5

2

1

(Front View Of Jack)

Typical Industry Standard

Non-Electronic Telephone

Making A Power Failure Station Connection

Installing The Loop Start Line Board – 9

IMI89–172 Installing The Loop Start Line Board

5.0 Making An Auxiliary Equipment

Interface Connection (Busy Lead Detection)

When needed, connect an industry standard non-electronic telephone device such as a FAX machine, an industry-standard telephone, or a data device, such as a modem, on a line ahead of the common equipment. The system will detect an off-hook condition in the connected device and turn on the status light for the line at the system telephones to indicate that the line is busy.

Each line board makes one auxiliary equipment connection available for use. This connection is at pins 1 and 6 of the lines 1,2 jack and is associated with line 2 of that line board.

PLUS066

Line Board

Line 1 Conn.

Line 2 Conn.

3

2

1

6

5

4

(Front View Of Jack)

Industry-Standard

Telephone Device

Such As: Fax

Machine, Model

2500 Telephone,

Modem, Etc.

(No A-Lead Control Required)

Making A Typical Auxiliary Interface Connection

Accredited by the Dutch Council for Certification for certification and registration activities.

Comdial’s Quality Management System Is

Certified To The ISO 9001 Standard.

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Charlottesville, Virginia 22901-2829

World Wide Web: http://www.comdial.com/