AT&T 518-600-016 User Manual

AT&T

518-600-016

®

MERLIN II

COMMUNICATIONS SYSTEM

Installation, Administration,

and Maintenance Manual

©1990 AT&T
All Rights Reserved
Printed in USA

January, 1990

Issue 2

NOTICE

The information in this document is subject to change without notice. AT&T
assumes no responsibility for any-errors that may appear in this document.

MERLIN is a registered trademark of AT&T.
HOLADAY is a trademark of Holaday Industries.

Section 1: System Description

What’s in This Manual

Section 1: System Description

Section 2: Installation
Section 3: Administration
Section 4: Troubleshooting
Section 5: Ordering Information

System Overview

System Configuration
System Features

System Hardware

MERLIN II System Components

Control Unit Components
Module Controls and Indicators
Voice Terminals
Basic Operation of Voice Terminals
System Accessories

1-1

1-1

1-1
1-1
1-1

1-1

1-2
1-4

1-7

1-18

1-18
1-18
1-23
1-25
1-29
1-31

Theory of Operation

System Architecture
Analog to Digital Signal Processing
Digital Switching
System Capacity

E&M Signaling

System Connectivity

Simultaneous Voice Data
Local Host Computer Access
Modem Pools
General Requirements for Modems
Music-On-Hold

External Loudspeaker Paging

1-36
1-36

1-40

1-42
1-44
1-45

1-52
1-52

1-54
1-54
1-58
1-60
1-60

What's in This Manual

This manual provides information about how to install and
maintain a MERLIN II Communications System. It covers
the MERLIN II System Feature Module 1, Feature Module
2, and Release 3. For further information on specific

features and options, see the

System System Manual

on data communications options with the MERLIN II
system, refer to the

Data Communications Guide

The information in this manual is divided into five
sections, as described below.

MERLIN

MERLIN

II

Communications

for that release. For information

mmunications System

II

Co

for the release.

SECTION 1: SYSTEM DESCRIPTION

SECTION 2: INSTALLATION

SECTION 3: ADMINISTRATION

SECTION 4: TROUBLESHOOTING

SECTION 5: ORDERING INFORMATION

This section provides a general overview of the system
and its components.

This section describes how to wire and install a MERLIN
II system.

This section tells you how to customize and administer the
system to meet specific business needs.

This section can help you isolate and solve technical

problems that may cause the system to malfunction.

This section tells you how to order MERLIN II system

components and accessories.

What’s in This Manual

1-1

System Overview

The MERLIN® II Communications System is a
programmable digital telephone system with many
features to make voice and data easy to manage. It

supports up to 56 outside lines and 120 stations, depending
on the configuration. Voice terminals allow access to the
system for conversations, feature programming, or system
administering. By connecting an optional printer to the
system, the user can receive a detailed call report of each

station’s activity and a printout of all system
administration.

The MERLIN II System is designed to handle integrated
voice and data calls without reducing system capacity. It
can support various terminal types: analog voice
terminals, digital voice terminals, and digital data
terminals. It also supports the new 7102A single-he
voice terminal, Touch-Tone (2500) telephones, and rotary
(500) telephones.

Data and voice options are implemented by selecting the
appropriate station module. There are three types of

station modules: analog modules for analog voice
terminals, basic telephone modules for 7102A, 2500, or
500 sets, and digitaI modules for digital voice terminals
and data devices. Station modules, used with system
accessories, allow the user to select from the simplest

method of voice and data communication to complex
arrangements such as data calls between two digital
stations and modem pooling. Refer to Figure 1-1 for an
example of MERLIN II system configuration.

1-2 System Overview

MERLIN II System control unit

Modern pool types

Digital Digital Digital

port port port

MTDM

Modern Modern

2500 Port

MTDM

BTMI

Analog

port

MTDM

Modern

Central

office

line

Analog voice and data

Voice Terminal

Voice Terminal

Voice Terminal

General

Purpose
Adapter

Power

supply

Local host access

Digital Digital

port port

MPDM MPDM

Host

Computer

Display

Console

34-Button

22-Button

10-Button

Modem

Processor
module

Terminal

or PC

Analog
station
module

Accessories/auxlliary

equipment

Telephone

and Modem

Interface 2

Music

Coupler

Single/Multizone

Paging
Alerter

Accessories

MERLIN II

Attendant

Basic

telephone

module

Basic

Tie

line

module

Digital voice and data

PT510D
Digital

Voice/Data

7406D

Digital

Voice

Basic voice and data

Modem

Digital
station

module

7406D/with
display
Digital Voice

7406D/with

Data Stand

Digital

Voice/Data

2500 Type

telephone

500 Type

telephone

Terminal

or PC

FIGURE 1-1 MERLIN II system configuration.

Answering

machine

Printer

System Overview 1-3

SYSTEM CONFIGURATION

The size, type, and features of a MERLIN II system are
determined using system planning forms.

System Size

A MERLIN II system can be as small as four outside lines
and eight analog voice terminals, or as large as 56 outside

72

lines and

stations. A MERLIN II system with as many

as eight lines and 20 stations is considered a small system

for administration purposes.
Basic and expanded system capabilities are determined by

these system hardware maximum limitations:

●

Thirty-six analog stations with the Simultaneous Voice

and Data feature

●

Sixty-four digital stations with the Simultaneous Voice

and Data feature

● Eleven line pools

●

Seventy-one off-premises devices or Basic Telephone

and Modem Interfaces

System Type

A system can be configured for pooled, square, or behind­switch operation. The MERLIN II system default
configuration is pooled with button access.

●

In a square system, each outside line has a dedicated

position on a voice terminal. This arrangement is also
known as a key system. In a standard square
configuration, outside lines appear on the same buttons
on each voice terminal. In a customized square
system, different groups of outside lines are assigned

to the same buttons on selected groups of voice
terminals.

1-4 System Overview

●

In a pooled system, outside lines can be grouped into

line pools (groups of interchangeable lines). To get an
outside line in a pooled system, the user must dial an
access number or use a dedicated pool button on the

voice terminal. Access to outside line pools can also
be had through Automatic Route Selection (ARS).

●

In a behind-switch system, the MERLIN II system

operates behind a larger system such as a System 25,
75, or 85 PBX. In this configuration, most features of
both systems are available to the MERLIN II system
user. Refer to Figure 1-2 for an example of a MERLIN
II system operating behind a digital PBX.

System Overview 1-5

Central

office

lines

\

25 Pair cable

/

Network

interface

66 Type
hardware

DIW cable

DIW cable

Digital PBX

(System 25,

System 75,

or System 85)

Jack Field

for outside

lines

Z122C Box

with

Z61OA

Adapters

D2R

cords

Power
Supply

408 408 408 408 408

PFT

04
03
02
01

08
07
06
05
04
03
02
01

PFT
08
07
06
05

16

15

14

13

12

11

10

09

PFT
12
11
10
09

24
23
22
21
20
19
18
17

PFT
16
15
14
13

32

31

30

29

28

27

26
25

PFT
20

18
17

40

19

39
38
37
36
35
34
33

D8W
cords

\

To voice

terminals

and

adjunct

equipment

/

MERLIN II System

contol unit

FIGURE 1-2 A MERLIN II system behind-switch operation.

1-6 System Overview

SYSTEM FEATURES

Table 1-1 lists the features that are available for
MERLIN II System Feature Modules 1 and 2, and
Release 3.

NOTE:

The features in Table 1-1 are described fully in

MERLIN II Communications System System

the

Manual.

The following paragraphs describe feature that are either

new in Release 3 or have been significantly modified for
Release 3.

●

Disallowed List.

Using a Disallowed List, you can
create up to eight lists of numbers, area codes, or
exchanges that selected users will not be permitted to
dial. Each list can have up to 10 numbers. The
administrator may assign one or more of these lists to
any station in the system. If a station is assigned so a
disallowed list any attempt to dial a number contained
in the list wiIl be denied.

●

Extended Station Status.

Extended Station Status (ES
Status) indicates the operating status of other stations
to the administrator. When ES Status is administered
for Hotel/Motel mode, the attendant can put voice
terminals into different categories to indicate whether
the room is occupied. With Release 3, if the voice
terminal is off-hook, the attendant can’t change its
status. This ES Status Inhibit feature helps prevent
hotel guests from making calls from their room after

they have checked out.

NOTE:

The alternative to Hotel/Motel mode is Call

Management System (CMS) mode. CMS is
the automatic call distributor (ACD) for the
MERLIN II system, and is available only with
Feature Module 1 or 2,

not

Release 3. The
CMS component of the MERLIN II system
answers calls and connects them to available

agents. CMS is not a system feature and
requires a separate software package.

System Overview 1-7

●

MERLIN II Attendant. The MERLIN II Attendant
automatically answers and routes incoming calls. The
feature is available only when the optional MERLIN II
Attendant accessory is installed. Also, to gain access
to this feature, you

must

use the517C13 Basic

Telephone (012) Module.
The MERLIN II Attendant performs two major

functions (Figure 1-3):

Immediate call handling, in which all incoming

>

calls are received and routed by the MERLIN II
Attendant. Multiple MERLIN II Attendants can
be used to handle call groups.

Backup call handling, in which incoming calls are

>

directed to the MERLIN II Attendant if the
receptionist (Station 10) does not answer within a
predetermined number of rings.

Each of these functions includes night service call
handling in which the MERLIN II Attendant maybe

used for call coverage only after normal business
hours.

●

On-Line Module Swap.

The On-Line Module Swap

feature allows you to replace a module in the control

unit without powering the system down. The
replacement module must be the same as the one

removed (i.e., a 408 module must be replaced with a
408 module). To use this feature, it is necessary to
follow the exact procedures described in “On-­Module Swap,w on page 4-7.

●

Page All.

This feature allows you to page all

telephones in the system at once over voice terminal
speakers.

1-8 System Overview

●

Posted Message.

The Posted Message feature
provides a method of sending one of 20 user-defined
messages to another terminal. Each message can be up

to 16 characters long and will appear on the caller’s
display.

●

System Speed Dial.

System Speed Dial allows the
caller to store frequently used numbers as three-digit
codes. For Release 3, the feature has been enhanced to
accommodate 130 speed dial numbers.

●

Tie Lines.

The MERLIN II system interfaces to a tie
line with E&M signaling through a Tie Line Module.
This feature permits the interconnection of a MERLIN
II system to another MERLIN II system or to other
switches such as a System 25,75, or 85 PBX. (See
“E&M Signaling” on page 1-45 for a description of
E&M signaling.)

System Overview 1-9

Call transferred to

receptionist;

MERLIN II Attendant

disconnects

▲

No

MERLIN II Attendant

answers call.

Caller
enters route
or extension

number.

No

Route

or extension

valid?

Yes

Route

or extension

answers?

No

Second

route or
extension
answers?

No

MERLIN II Attendant
plays Transfer Fail

announcement.

Yes

Yes

call transferred; connection

announcement played;

MERLIN II Attendant

disconnects.

Does

No

caller select
another route
or extension?

Yes

FIGURE 1-3 MERLIN II Attendant operation.

1-10 System Overview

Repeat process

TABLE 1-1 MERLIN II System Features

Feature

Account Code Entry
Allowed List
Attendant (Automatic) [MERLIN II Attendant]
Attendant Barge-in
Attendant Position Setting
Auto Answer All
Auto Answer-Intercom
Auto Intercom
Automatic Line Selection (ALS)
Automatic Route Selection (ARS)

FM1 FM2

1

x
x

x
x

x

x

x

x

x
x

x
x x
x x

x x

Release 3

x
x

x

2

x

x
x
x

x
x

x

Basic Telephones

x x

Behind-Switch Operation

3

Bridging on Shared Lines
Call Coverage

1 The feature name is "Account Number Entry- for Feautre Module 1.
2 The feature name is ‘Executive Barge-In
3 The feature name is “Bridging” for Feature Module 1 and Feature Module 2

-

for Release 3 and can be used from any voice terminal.

x

x

x

x

3

x
x

x

x
x

System Overview 1-11

TABLE 1-1 MERLIN

II

System Features (continued)

Feature

Call Forwarding and Follow Me
Call Park
Call Pickup
Call Pickup Groups
Call Report (SMDR)
Call Restriction
Camp On
Centralized Programming
Conference
Coverage Inhibit

FM1

FM2

Release 3

x x

x x x

4

x

4

x

x
x
x

x

x x

x x

x
x
x

x x

x x

x

4

x

x
x

x
Dialing Timeout Internal for Rotary Lines
Direct Inward System Access (DISA)

x

x

x
Disallowed List
Display
Do Not Disturb
Drop

4 This feature in Feature Module 2 and Release 3 is the same as "Line Pickup” in Feature Module 1.

x
x x
x x

x

x
x
x
x
x
x

1-12 System Overview

TABLE 1-1 MERLIN II System Features (continued)

Feature

Executive Barge-In
Extended Station Status (ES Status)
Flexible Numbering

Follow Me
Forced Account Code Entry (FACE)
Group Call Distribution (GCD)

Group Listening
Group Page

Hold
Hold Disconnect Interval

FM1

x

x

x

x

x

FM2 Release 3

5

x
x

x

x

x x

x

x

x
x x

6

x

x
x

7

x x
x

x

x

x
Intercom
Intercom Dial Tone
Labels for Lines and Stations
Last Number Redial

5 For Feature Module 2, the feature name is “Attendant Barge-In” and it operates only from an attendant

station.
6 For Release 3, the feature name is “Call Forwarding and Follow Me”
7 The information for this feature is found in Section 2, "System Components," of the System Manual for

Release 3.

8 For Feature Module 2, the feature name is "labels for Stations” and it is limited to stations only.

x x

x x
x

x x

8

x

x
x

System Overview 1-13

TABLE 1-1 MERLIN II System Features (continued)

Feature

Leave Word Calling
Line Assignments in Behind-Switch Systems
Line Assignments in Pooled Systems
Line Assignments in Square Systems

Line Pickup
Line Representation Setting
Line Request

Loudspeaker Page
Manual Signaling

Menu Driven Administration

FM1

x

FM2 Release 3

x

x

9

x

10

x

11

x

x

x

x

x

x x

12

x
x x
x

x

x x x

x

x

x

x

12

x

13

x

Message
Monitor-on-Hold

9 The feature name is "Line Pools" for Feature Module 1.
10 The feature name is "Square Line Configuration" for Feature Module 1.
11 This feature is called "Call Pickup" for Feature Module 2 and Release 3.
12 The feature name is “System Type” for Feature Module 2 and Release 3.
13 This is not technically a feature of MERLIN II System with Release 3, since menu-driven is the only

administration method for that release. See “Overview” in Section 3, "Reference," of the Release 3 System
Manual for information on menu-driven administration.

14 The information for this feature is found in Section 2, "System Components," of the System Manual for

Release 3.

x x x

x

x

14

x

1-14 System Overview

TABLE 1-1 MERLIN II System Features (continued)

Feature

Music-on-Hold
Night Service

Notify
On-Hook Dialing
On-Line Module Swap

One-Touch Hold with Call Announcement

Outside Auto Dial
Page All
PBX, Centrex, or Custom Calling Features
Personal Speed Dial

FM1

FM2 Release 3

x x
x

x
x

x
x

x

x x x

x

x

x x

x

x

x
x

x

15

x

x

x
x

x

Personalized Ringing
Posted Message
Privacy
Reed
Recall Timer Interval

Reminder Service

15 The information for this feature is found in Section 2, "System Components," of the System Manual for

Release 3.

x

x

x x x
x
x

x
x

x

x
x

x
x
x

System Overview 1-15

TABLE 1-1 MERLIN II System Features (continued)

Feature

Ringing/Idle Line Preference
Ringing-on-Transfer
Ringing Options

Saved Number Redial
Send Message
Simultaneous Voice and Data Calls
Special Characters in Programmed Dialing Sequences
Stopwatch
System Renumbering

System Size

FM1

16

x
x

x x
x
x

x

x

x

x

17

x

FM2

Release 3

x x
x

x
x x
x x
x
x
x
x

x

x

x

x
x
x
x

System Speed Dial
System Type

Test

16 The feature name is “Ringing Line Preference” for Feature Module 1.
17 The feature name is “System Size Setting- for Feature Module 1.
18 This feature name is "Line Represention Setting" for Feature Module 1.
19 The information for this feature is found in Section 2, "System Components," of the System Manual for

Release 3.

x

18

x

x

x

x
x

x

x

19

x

1-16 System Overview

TABLE 1-1 MERLIN II System Features (continued)

Feature

Tie Lines

Tones
Touch-Tone Enable
Touch-Tone or Rotary Signaling
Transfer

Transfer Return Interval
Type of Telephone

Voice Announcement Enable/Disable

Voice Announcement to Busy Telephone

FM1

x

x

21

x
x
x

22

x

x

23

x

FM2

x

x

x

x
x

22

x

x

23

x

Release 3

x

20

x

x

x

x

x

x

x

x

20 The information for this feature is found in Section 2, “System Components,” of the System Manual for

Release 3.
21 The feature name is "Touch-Tone or Rotary Setting" for
22 The feature name is "Voice Terminal Type Setting" for Feature Module 1, and "Voice Terminal Type" for

Feature Module 2.
23 The feature name is "Voice Announcement to Busy Voice Terminal" for feature Module 1 and Feature

Module 2.

Feature

Module 1.

System Overview 1-17

System Hardware

MERLIN II SYSTEM

COMPONENTS

CONTROL UNIT COMPONENTS

The MERLIN II system includes the following hardware:

●

Control unit
Voice terminals

●

> Analog
> Digital

●

Basic Touch-Tone

●

Digital data equipment

●

Modems

●

System accessories/auxiliary devices

The assembly of modules containing a power source, a
processor, and jack connections for outside lines, tie lines,
MERLIN II system telephones, and other devices mounted
on a carrier is called the control unit (Figure 1-4). The
individual components are as follows:

●

Basic carrier.

The basic carrier is the main housing
for the control unit. Every MERLIN II system must
have at least one basic carrier, which houses the Power
Supply Module, Processor Module, and up to five line
and/or station modules.

● Expansion carrier. The expansion carrier provides

slots for an additional Power Supply Module and six
line and/or station modules. The expansion carrier
does not require a Processor Module.

1-18 System Hardware

Basic carrier

FIGURE 1-4 Control unit components.

●

Power Supply Module. The Power Supply Module

receives an input of 117 VAC and supplies the system
with the following dc voltages: +5, -5, and -48 VDC.
The Power Supply Module can support up to 45 unit

loads per carrier. (A unit load is a measure of power
used to determine the electrical load of the MERLIN II
system.) if the system’s power requirements exceed 45
unit loads, an Auxiliary Power Unit must be used. This
device supplies an additional 20 unit loads to the
system. For more information on unit loads and the
Auxiliary Power Unit refer to “Determining Unit Load
Requirements” on page 2-57.

If the system uses Basic Telephone (012) Modules, a
Frequency (Ring) Generator must be installed in the
Power Supply Module.

Expansion

carrier

System Hardware 1-19

Power supply

module

Processor

module (R3)

(with feature

module)

Processor

module

(FM1 and 2)

(with feature

module)

Line/station

module

(408)

Station

module

(000)

Line module

with DTMF

(400)

Line

module

(800)

Tie line
module
(400EM)

FIGURE 1-4 Control unit components (continued).

1-20 System Hardware

Digital

station-module

(008D)

Basic

telephone

module

(012)

●

Processor Module.

The Processor Module contains
the circuitry that controls the system’s programs and
features. It houses the Feature Module. Release 3 of
the MERLIN II System must use Processor Module

517B7 with Feature Module 517F6.

● Feature Module. The Feature Module contains the

Read Only Memory (ROM) and Random Access
Memory (RAM) for the system features. It is housed
inside the Processor Module. The MERLIN II Release
3 Feature Module(517F6) must be used only with the
517B7 Processor Module.

● Line and station modules. Line and station modules

provide jacks for the system’s tie lines, outside lines,
and stations. Line and station modules can occupy
slots 1 through 5 in the basic carrier and slots 6
through 11 in the expansion carrier. There is no
required slot assignment for line and/or station
modules except that the module in slot 1 of the basic
carrier must be a 408 or 008 module. Either of these
modules provides the user with an analog station port

(port 01) to administer the system.

> Analog line and station modules:

—

4-Line/8-Analog (408) Module.

module is required for a MERLIN II system
minimum configuration. It has four jacks for
outside lines and eight jacks for analog
stations. The 408 module has a Power Failure
Telephone (PFT) jack for connecting a Basic
Touch-Tone or rotary telephone for backup
during power outages. The system
automatically switches service to this jack in
the event of a power failure.

Simultaneous voice and data is available but
requires you to connect both an odd and even
numbered jack to the same voice terminal.

The 408

System Hardware 1-21

– 8-Analog (008) Module. The 008 module has

jacks for eight analog stations. It has no jacks

for outside lines. Simultaneous voice and data

is available but requires you to connect both
an odd and even numbered jack to the same
voice terminal.

– 4-Line (400) with DTMF Module. The 400

module has jacks for four outside lines and one
PFT jack. The board has four Touch-Tone
receivers.

– 8-Line (800) Module. The 800 module has

jacks for eight outside lines and two PFT

jacks.

>

E&M Tie Line (400 EM) Module. A tie line is a
transmission facility dedicated to interconnect two
private switching systems. The MERLIN II system
Tie Line Module may be connected to another
system locally or many miles away. Tie lines are
provided by the telephone company.

>

Digital (008D) ModuIe. The 8-station digital
module interfaces digital voice and data equipment
to the system. Simultaneous Voice and Data is
available on every port.

>

Basic Telephone (012) Module. The Basic
Telephone Module permits Touch-Tone or rotary
telephones to be used with the MERLIN II system.
This module provides 12 station jacks and supplies
the tip/ring interface and Touch-Tone circuitry
needed for basic telephones. This module requires
the installation of the Frequency Generator in the
Power Supply Module.

The 517CI 3 Basic Telephone Module must be
installed in order to use the MERLIN II Attendant.

1-22 System Hardware

Label

Power indicator

Auxiliary power
input jack

On/Off switch

Power
connector

Ground lug

Power supply module

FIGURE 1-5 Module controls and indicators.

MODULE CONTROLS AND INDICATORS

The from panel controls, indicators, and special

connectors (excluding line and station jacks) on control
unit modules are described below. Refer to Figure 1-5 to
locate these items.

Diagnostic
96-pin connector

SMDR port

Application port

Warning light

Pr

ocessor module (517B7)

for Release 3

Power Supply Module.

The controls and indicators for

this module are the following:

●

Power indicator. Its light goes on when power is

supplied to the module.

●

Auxiliary power input jack This jack provides the
interface for the Auxiliary Power Unit.

System Hardware 1-23

Label

SMDR port

Application port

Status indicators (LEDs)

DIP switch (S2)

Port 4

Port 3

Port 2

Port 1

DIP switch (S1)

Tie line module (517A14)

Warning iight

label

Diagnostic
96-pin connector

Processor module (517A7)

for Feature Moduies 1 and 2

FIGURE 1-5 Module controls and indicators (continued).

●

On/off switch. This switch applies or removes power

to the earner.

●

Power connector. This is a male connector for the ac

power cord.

●

Ground lug. This connects the control unit chassis to

an approved ground for the building.

1-24 System Hardware

Processor Module.

This module has the following port

and light:

● SMDR port. This port is an interface to Station

Message Detail Recording (SMDR) for call reports on
call activity or a printout of system administration.

●

Warning light. When this red light is lit it indicates

that there is a problem with either the Feature Module,
line or station module, or the Processor Module.

Tie Line Module. The controls and indicators for this
module are the following:

●

Status indicators (LEDs). The three status indicators

show the condition of the Tie Line Module.

Green = test condition
Amber = busy
Red = standby mode

●

Dual In-Line Package (DIP) switch (S2). This switch

controls the signaling format for tie line ports 3 and 4.

VOICE TERMINALS

●

DIP switch (S1). This switch controls the signaling

format for tie line ports 1 and 2.

●

Ports 4 through 1. These ports are jacks for tie lines.

Voice terminals are the user’s link to the MERLIN II
system. They are designed to allow easy access to system
features, and have various buttons and indicators to
facilitate operation The buttons on a voice terminal can
function as line buttons or feature buttons. There are fixed
feature buttons for the transfer, hold, recall, conference
and drop features.

Each analog voice terminal has a Test/Program (T/P)
switch that allows testing, programming, and normal
operation. Digital voice terminals are programmed using
a dial code. Other controls on a voice terminal include a
message button, speaker volume control, speaker ON/OFF
button, and red and green lights to indicate status of lines
and features.

System Hardware 1-25

Voice terminals work like special input/output (I/O)
devices. The control unit performs all the decision making
for the system while voice terminals act as the system’s
sensors. Voice terminals inform the control unit of button
depressions and feature status. They also inform the user
of specific conditions by flashing lights or generating
tones.

Voice terminals are connected to the control unit by a
4-pair wire. Each pair has a specific function:

●

Voice 1 pair. The control unit uses this pair of wires
for the primary audio path to and from the voice
terminal. The control unit selects this pair to complete
the path for outgoing, incoming, and intercom calls.

●

Control pair. The control unit receives information
on voice terminal status and user input on this pair of
wires. It also uses this path to send ringing and lighting
instructions to the voice terminal.

●

Power pair. This pair provides power to the voice
terminal.

●

Voice 2 pair. The control unit uses this pair of wires
for the secondary audio path to and from the voice
terminals. This pair is used with the analog voice
terminal to provide the Voice Announcement to Busy
Voice Terminal and the Simultaneous Voice and Data
features.

Voice terminals used with the MERLIN II system are
listed here. Refer to Figure 1-6 for examples of analog

voice terminals, including the MERLIN II Display
Console. Figure 1-7 shows digital voice terminals.

1-26 System Hardware

● Analog voice terminals

>

7102A

>

5-Button

>

10-Button

>

10-Button HFAI

10-Button with Built-In Speakerphone (BIS-10)

>

BIS-22

.>

BIS-22 with Display

>
>

34-Button

>

34-Button Deluxe

>

34-Button (SP-34)

>

34-Button (SP-34D)

>

BIS-34

>

BIS-34 with Display

>

Display Console (used to administer a system with
Release 3)

NOTE:

The new 7102A single-line voice terminal

(not illustrated) has been certified for the
MERLIN II system. It is the same as a basic
telephone and must be connected to a 012
module.

●

Digital voice terminals

> 7406D
> 7406D with Display
> 7406D with Data Stand

> 7406D with Display and Data Stand

System Hardware 1-27

10-Button

10-Button

HFAI

BIS-10

BIS-22D

with display

BIS-34

34-button

BIS-34D

with display

Display console

FIGURE 1-6 A selection of analog voice terminals.

1-28 System Hardware

7406D with
Data Stand

FIGURE 1-7 A selection of digital voice terminals.

7406D with
display and

Data Stand

BASIC OPERATION OF VOICE TERMINALS

Voice terminals perform a variety of functions. With a
voice terminal, a user can make and receive intercom and
outside calls, page someone, and, with the proper voice
terminal (the attendant console), administer the MERLIN

II system. Buttons on voice terminals maybe
programmed for different functions. The following
paragraph describe the basic operations of voice

terminals.

●

Administration. Two voice terminals, the Display
Console and the BIS-34D, can be used to administer
systems with Feature Module 1 and Feature Module 2.

The Display Console, however, is the only voice

terminal that can administer new MERLIN II Release
3 features. The voice terminal used for administration
must be connected to station jack 01 on the control
unit. During administration, the voice terminal

Test/Program switch must be set to “Program”. This
switch is set to the center position during normal
operation

System Hardware 1-29

●

Dialing out or in.

When a voice terminal goes off­hook, it signals the control unit to make a connection
through a network switch to an available or requested
outside line. When the path is established, the voice
terminal receives a dial tone. The control unit will
select a path in its multiplexing scheme to make the
connection. A call coming into the will
activate the ring indicator in the control unit and
generate control signals to alert the voice terminal.

●

Intercom call.

Intercom calls can be made from one
voice terminal to-any other voice terminal connected to
the control unit. Dialing the intercom number of
another voice terminal will cause the control unit to
establish a voice path between both voice terminals.

●

Loudspeaker paging.

The system interfaces with
auxiliary equipment such as a power amplifier and
loudspeaker for single or multiple zone external
paging.

●

Programming.

In programming mode, instructions
keyed into a voice terminal are stored in the control
unit’s memory; the voice terminal itself has no
memory. When a particular feature is requested by a
voice terminal, the control unit examines its memory to
determine the features for that station.

For an analog voice terminal, you enter and exit
programming mode by using the T/P switch. For a

digital voice terminal, which doesn’t have a T/P
switch, you must use a dial code to enter and exit

programming mode. For a basic voice terminal, the
administrator must program any feature changes.

●

Telephone paging.

The MERLIN II system allows

paging over voice terminal speakers. The Group Page

feature allows paging to a maximum of 10 voice
terminals. The Page All feature allows paging to all
voice terminals in the system.

1-30 System Hardware

SYSTEM ACCESSORIES

Figure 1-8 shows several of the MERLIN II system
accessories described here.

●

Alerter Accessories.

Devices such as a horn, bell,
strobe, or chime can be connected to a Supplemental
Alert Adapter so that people working in noisy or
remote areas of a building can be alerted to incoming
calls.

●

Attendant Intercom Selector.

Can be attached to a
34-Button Deluxe voice terminal when a MERLIN
system has more than eight lines or more than 20 voice
terminals. A system attendant can use the selector’s 30
buttons to access up to 120 Auto Intercom numbers.
The light beside each button indicates whether a voice
terminal or basic telephone is busy and whether a
voice terminal’s message light is on.

●

Auxiliary

Power Unit. This unit must be added to the
control unit if the total number of voice terminals and
voice terminal accessories (including Hands-Free
Units and Headset Adapters) is greater than the control
unit’s power capacity. The control unit supports up to

45 unit loads, and each Auxiliary Power Unit adds 20
unit loads to the system.

●

Basic Telephone and

Modem Interface.

The BTMI
connects telephones and data communications devices
such as autodialers, answering machines, cordless
telephones, facsimile machines, and modems to the
MERLIN II system. A timer may be connected to a
BTMI for automatic answering based on time of day.

The BTMI is no longer available, having been
replaced by the BTMI-2. The BTMI supports more
features than the BTMI-2, however, including the
Conference and Drop features, and line selection. For
customers who already have the BTMI, it can be used
with MERLIN II systems with Feature Module 1,
Feature Module 2, and Release 3.

System Hardware 1-31

Basic Telephone and Modem

interface 2 (BTMI-2)

Off-Premises Telephone

Interface (OPTI)

General Purpose

Adapter (GPA)

In-Range Out- of-

Building Protectors (IROB)

Hands-Free Unit (HFU)

Headset with Headset Adapter

Indoor

bell

Extra alert

strobe

Alerter accessories

FIGURE 1-8 A selection of MERLIN II system accessories.

Indoor

horn

Indoor/outdoor

alerter

1-32 System Hardware

● Basic Telephone and Modem Interface 2 (BTMI-2).

The BTMI-2 is a replacement for the BTMI. It
connects telephones and data communications devices
such as autodialers, answering machines, cordless
telephones, facsimile machines, and modems to the
MERLIN II system. A timer may be connected to a
BTMI-2 for automatic answering based on time of day.

Unlike the BTMI, the BTMI-2 does not support
Conference, Drop, or line selection features. It can be
used with MERLIN II systems with Feature Module 1,
Feature Module 2, and Release 3.

●

Basic Telephones.

Basic Touch-Tone telephones,
connected to the MERLIN system with the Off­Premises Telephone Interface (OPTI) and to outside
telephone lines, provide service to people at a remote
location. On-premises Basic Touch-Tone telephones
can be connected to the system with a Basic Telephone
and Modem Interface 2 or a Basic Telephone Module.

●

Frequency Generator.

If your basic carrier or
expansion carrier has a Basic Telephone (012)
Module, you must connect a Frequency Generator to
the Power Supply Module, located in the first slot of
each carrier containing Basic Telephone Modules.

The Frequency Generator converts 117-volt, 60-Hz
input power to 105-vol~ 30-Hz ringing voltage for
basic telephones connected to the Basic Telephone
Module.

●

General Purpose Adapter

(GPA). Permits
connection of accessories such a modem with PCs or
data terminals, cordless telephones, and autodialers to
a MERLIN II system voice terminal. To use this
accessory, you must program Auto Answer AU. The

GPA is for use with all analog voice terminals except

5-button and 10-button HFAI.

System Hardware 1-33

●

Hands-Free Unit (HFU).

Provides the voice terminal

user with full speakerphone capability. This includes
hands-free telephone conversation, on-hook dialing,
monitor-on-hold, and teleconferencing at a short
distance from the voice terminal. To use this

UtO

accessory, you must program A

Answer- Intercom.
The HFU is for use with all analog voice terminals
except 5-button and 10-button HFAI. An HFU used

with a 7406D voice terminal requires a local power
unit.

●

Headset-and-Headset- Adapter.

Enables a user

to

answer and listen to calls without lifting the handset.
The headset and headset adapter is for use with all
analog voice terminals except 5-button and 10-button
HFAI.

●

In-Range, Out-of-Building (IROB) Analog Voice
Terminal Protectors.

A voice terminal can be placed
in another location outside of the main building but
within 1000 feet of the MERLIN H system control
unit. IROB protectors protect the control unit and
voice terminal from exposure to lightning, contact with

power lines, and power currents induced by nearby

power lines.

1-34 System Hardware

●

Loudspeaker Paging System.

An optional
loudspeaker paging system allows people with
MERLIN II system voice terminals to page co-workers
and/or make announcements through loudspeakers.

●

Music Coupler.

A music coupler connects a music

source (such as a cassette player) to the MERLIN II
system. It also provides a secondary bridged
connection to provide Music-on-Hold. In addition, it
allows the music source to be connected to a
loudspeaker paging system to provide background
music at the same time.

●

Off-Premises Range Extender (OPRE).

The OPRE
will be available in place of the Off-Premises
Telephone Interface (OPTI) for users of Feature

Module 1, Feature Module 2, and Release 3. The
OPRE will allow users to connect off-premises
Touch-Tone Basic telephones to the MERLIN II
system.

NOTE:

As of this printing the Off-Premises Range

Extender is not available. Installation

information will be supplied in a CIB with the
product.

●

Off-Premises Telephone Interface (OPTI).

Connects off-premises Touch-Tone Basic telephones
to the MERLIN II system. Allows you to use an off­premises telephone to access many of the features of
the on-premises communication system. The OPTI is
used with MERLIN II Feature Module 1. It can also
be used with Feature Module 2 and Release 3, but only
for two-digit intercom numbers.

●

Power Failure Telephone.

A power failure telephone
allows calls to be made and received in case of a
power failure. A Basic Touch-Tone or rotary
telephone, when connected to a Power Failure

Telephone jack on a module in the control unit, bridges
onto the lowest line number in the block of jacks that it
serves on the module when a power outage occurs.

●

Supplemental Alert Adapter.

Allows Extra Alert
Devices, such as a horn, bell, strobe, or chime, to be
connected to an analog voice terminal jack so that
people working in noisy or remote areas of a building
can be alerted to incoming calls.

System Hardware 1-35

Theory of Operation

SYSTEM

ARCHITECTURE

The MERLIN II system architecture provides a digital
network that supports voice and data communications.
The modular nature of the system makes the base
configuration efficient and easy to expand. The control
unit contains the memory for the system’s features,
Input/Output (I/O) functions, and interface requirements.
The various modules are electrically connected to a
backplane assembly that provides common circuitry for
the I/O bus, Time Division Multiplex (TDM) bus, and
power distribution. Refer to Figure 1-9 for a fictional
block diagram of MERLIN II system architecture. System
architecture is made up of the following items: a
Processor Module interconnected to intelligent port
modules by an I/O bus; a communications network made
up of a TDM bus connected to the DigitaI Switch Element
(DSE) of each module; and a Power Supply Module.

1-36 Theory of Operation

FIGURE 1-9 System architecture.

Theory of Operation 1-37

●

Power Supply Module.

The Power Supply Module
converts 117 VAC line voltage to the following
outputs: +5 VDC, -5 VDC, and -48 VDC (tip/ring).

●

Processor Module.

The central processor complex
consists of a main board and the Feature Module. The
main board contains the 68000 microprocessor, RAM,
a real-time clock, interrupt circuitry, and port interface
to the modules through the I/O bus.

Communication between the Processor Module and
the port processors on the various modules occurs over
a parallel address/data bus. This structure allows
memory-mapped I/O with up to 1 megabyte per second
bandwidth.

●

Input/Output Bus.

Included in the I/O bus are a 16­bit address bus and an 8-bit data bus. The address bus
selects the module that receives instructions from the
68000 microprocessor. The microprocessor provides
instructions to the port processors and Digital Switch
Elements (DSEs) through the 8-bit data bus.

●

Time Division Multiplex Bus.

The Time Division
Multiplex bus (TDM) is a major part of the control
unit. It connects the DSEs to allow voice and data to
flow in and out of the MERLIN II system. The TDM
bus is parallel, 8 bits wide, and runs at 2.048 MHz.
Each TDM cycle has 256 time slots for voice, data,
tones, and clocks.

Voice signals on the TDM bus are encoded in “Mu-

Law 255” Pulse Code Modulation (PCM) format for
domestic use and “A-Law 100” for international
applications. See “Analog to Digital Signal
Processing” on page 1-40. Data signals are processed
according to Digital Communications Protocol (DCP).

●

408 or 008 Module.

A 408 Loop Start Line/ATL
Station Module or 008 module is required in slot 1 of
the basic carrier of the control unit. Note, however,
that the 008 module does not provide any outside lines

1-38 Theory of Operation

If you use a 008 module in this slot, you must provide
for outside lines using another module.

The 408 module has a port processor to handle real-

time intensive tasks such as ATL line protocol and

central office rotary outpulsing. The port processor

receives instructions from the main processor over the
I/O bus. The instructions are stored in the dual port
RAM. Buffer circuitry interfaces the I/O bus to the
port processor.

The 408 module converts analog signals to digitaI for
switching. Analog signals come into the 408 module
through the outside lines and are converted to digital
levels by coder-decodes (codecs). Voice and data

signals going to the station jacks are converted to
analog signals by codecs. Interface circuitry couples

the analog output to the station jack. The DSE

interfaces voice and data with the TDM bus. The main

processor (through the 1/0 bus) directs the DSE to

place or remove samples from the TDM bus in specific
time slots.

●

008D Module.

The 008D Digital Module provides a
digital interface to the system for PCs and other data
devices. This module does not require codecs because
no analog to digital conversion is required. Data flow
through the module is controlled by the port processor,
which receives its instructions from the I/O bus. Dual
Line Interface (DLI) circuitry assures proper clocking
and synchronization during all transfer cycles.

●

012 Module.

The 012 Module interfaces basic

telephones to the MERLIN II system. It provides the

-48 VDC tip/ring voltage and monitors the circuit for
tip/ring conditions. The 012 module converts analog
signals into digital levels for interface to the TDM bus
and provides -24 VDC for the Ring relay. When a
basic telephone goes off-hook and dials a number, ring
control circuitry closes the ring voltage relay. At this
point, ring control circuitry outputs signals to the port

Theory of Operation 1-39

processor. The port processor directs Touch-Tone

circuitry to output tones. The tones are placed on the
TDM bus by the DSE through buffer circuitry. After a
tip condition occurs at the remote end, a conversation
may occur.

ANALOG TO DIGITAL
SIGNAL

PROCESSING

Analog to Digital
Signal Conversion

The MERLIN II system receives analog signals from the
central office lines and analog modules. In order to be
switched, the analog signals must be converted to digital

signals. Digital transmissions have several advantages
over analog transmissions. They produce superior bit
error rates and have lower noise/signal degradation,
simpler circuitry in some cases, and greater flexibility.

They also have various performance advantages, such as

speed and a nonblocking architecture.
If an analog signal is sampled in increments equivalent to

twice the frequency of that signal, then the sample can
faithfully reproduce the signal at a digital level.

The first step in analog to digital conversion is to sample

the pulse amplitude of the analog signal. Then the sample
is converted into a series of amplitude steps. This
technique is referred to as Pulse Amplitude Modulation
(PAM). Analog to digital converters (codecs) are an
integral part of voice and data systems. Codecs use a
variety of encoding techniques. The MERLIN II system
uses Pulse Code Modulation (PCM).

1-40 Theory of Operation

The process of converting an analog signal to a digital

level increases the capacity and efficiency of data
transmissions. However, a digitized analog signal retains
some of the problems of older transmission systems, such
as having to be amplified.

PCM uses PAM as its starting point but goes further.

PCM digitizes the information and sends the 8-bit code via
PAM. PCM digitizes the PAM information by comparing
each PAM sample to a point on a chart. Each point has a
distinct 8-digit binary code. Therefore, it is the binary
code, not the amplitude pulse, that is transmitted in PCM.

Quantizing

Commanding

The process of converting PAM samples into discrete

PCM values is known as “quantizing”. In the case of voice

grade signals eight bits are commonly used to encode one
PAM sample. Quantizing with eight bits allows 256

unique values to represent the analog signal being

sampled. With adequate sampling of an analog voice
signal, the digital product can be toll quality.

The quantizing process creates errors due in part to the

“rounding off” of PAM samples into discrete PCM values.

This distortion can be minimized by increasing the number
of bits used to sample the analog signal or to increase the

sampling rate.

Distortion also occurs in the quantizing process because

equal consideration is given to all amplitude levels. Linear

quantizing divides the amplitude range into equal
segments which results in unnecessary quality at levels
where voice signals are unlikely to occur. Commanding
eliminates this distortion by using a nonlinear scale which
has smaller divisions and more accuracy in areas of the
scale where voice signals are most likely to occur.

Commanding is, in effect, a compression/expansion of the
quantizing scale. This nonlinear scale is more accurate in

areas where signal amplitudes occur most (thereby
reducing quantizing distortion). The scale is less accurate

in areas where signal amplitudes occur least (resulting in
more quantizing distortion).

Theory of Operation 1-41

Mu-Law 255

Mu-Law 255 is a commanding scheme which uses a
compression ratio that is compatible with modern channel
bank equipment. The scale is divided into 16 intervals,
with each interval having 16 levels. Therefore, it has 256

discrete values. Mu-Law 255 has a negative and positive
zero; therefore, it really has 255 discrete values. This
commanding scheme is used in the United States and
Japan.

A-Law 100

DIGITAL SWITCHING

The commanding scheme used in Europe is A-Law. It
follows the same basic theory as Mu-Law 255 except that
its scale is different. The scale tends to be more linear than
Mu-Law 255. Because the intends tend to be equal, A­Law 100 does not concentrate its accuracy in areas of the
scale where voice signals occur the most.

The Time Division Multiplex (TDM) bus allows many

users to communicate over a common electrical

connection. The TDM bus is physically distributed across
the backplane of the control unit and connects all
line/station modules. It is 8 bits wide and has a frequency
of 2.048 MHz. The frame repetition rate is 8 KHz
providing a 64 Kbps channel on each of the 256 time slots.
The TDM bus has specific time slots for various functions.

During a conversation between station A and station B, a

time slot is reserved for station A to transmit on and

another for station B to receive on. Because the TDM bus
cycles 8 thousand times per second, the conversation is
continuous. The TDM bus carries tones and control

signals to stations. Unlike other bus configurations, the

stations on the TDM bus receive all transmissions. If a

station is not assigned to any of the time slots, the TDM

bus will ignore the data. Refer to Figure 1-10 for an

example of the TDM bus.

1-42 Theory of Operation

The Digital Switch Element (DSE) functions as a digital

switch for voice and data. It also performs the operations
for commanding schemes such as A-Law and Mu-Law.

Each module has a DSE to interface codecs or digital
transceivers to the TDM bus. The actual digital switching
occurs when the DSE is programmed by the system I/O
bus to place (transmit) data or retrieve (receive) data on
the TDM bus in specific time slots. This process also
involves time slot interchanging so that an available slot in
the TDM cycle can be filled with a talk (transmit) or listen
(receive) slot. The DSE provides dynamic conferencing
ability by allowing up to 16 time slots to be conference
together and sent out to a single port (station).

DSE

0 1 2 3

Time slots
for control
signals.

408 Module

CODEC

D/A

converter

A/D

converter

…

i
n
t
e

Analog

r

voice

f
a

terminal

c
e

TDM Bus

256 Time slots in one TDM cycle

60 61 62 63

Time slots
for tones.

…

FIGURE 1-10 Time division multiplexing.

DSE

150 … 160

Analog station
talks on time
slot 150 and
listens on time
slot 160. The
conversation

is continuous.

008D Module

…

200 … 220 … 225

Interface

circuity

Time

Digital station
sends data on
time slot 200
and receives
data on time
slot 220.

Theory of Operation 1-43

SYSTEM CAPACITY

The MERLIN II system hardware limits the system
capacity for the items found in Table 1-2.

TABLE 1-2 MERLIN II System Capacity

Item

Module slots
Board signatures
Time slots

-

Simultaneous duplex connections

Tones

Capacity

17

16

256

108

40

Table 1-3 lists items that the system architecture either
allows or requires.

TABLE 1-3 Port Requirements for Features and System

Accessories

Feature

Port Requirements

1-44 Theory of Operation

Music-on-Hold interface

1 CO line (administered)
External paging interface
Analog Simultaneous Voice/Data
Analog Voice Announcement

to Busy Voice Terminal
Digital Simultaneous Voice/Data

Extra alert devices (with SAA)

1 ATL station port

1 CO line (administered)
2 ATL station ports

2 ATL station ports
1 DCP station port

E&M SIGNALING

Most signaling systems, other than loop signaling, are

separate from the trunk equipment. They are normally
located between the trunk equipment and the line facility.
E&M signaling systems derive their name from the
historical designations of the signaling leads on
schematics covering these systems. By convention, the
"E" stands for ear and the "M" stands for mouth (rEceive
and transMit). The E&M lead signaling interface consists
of two leads between the switching equipment (central
office) and the signaling equipment (PBX). The “M lead
carries signals from the switching equipment to the
signaling equipment. The “E” lead carries return signals
from the signaling equipment to the switching equipment.
The E&M interface is designated as TL31M, and the 50-

pin connector is designated as RJ2GX. At the RJ2GX
interface, the PBX is the switching equipment side, and
the network side (toward the central office) is the

signaling equipment side. An example of E&M signaling

is shown in Figure 1-11.

Theory of Operation 1-45

MERLIN II

System

T
R
T1
R1
M
E

RJ2GX

Central

office

Central

office

RJ2GX

T1
R1
T
R
E
M

Dimension

PBX

SITE #l

Off-hook

Dial tone
Site #1 dials
number for
site #2

On-hook

M lead

E lead

E lead

M lead

FIGURE 1-11 E&M signaling.

M lead of site #1 connected to
E lead of site #2

M lead of site #2 connected to
E lead of site #1

Conversation

Disconnect

Disconnect

SITE #2

E lead

Ring

Off-hook

M lead

On-hook

M lead

E lead

E&M Tie Line
Parameters

1-46 Theory of Operation

The MERLIN II system 400EM Tie Line Module has four

line ports. Each must be administered individually. All tie
line options are software administered except for the

signaling format parameters (signaling mode and signaling
type). These are selected by DIP switches on the Tie Line
Module. The following is an explanation of tie line

options. For more information, see “Administering Tie
Lines” on page 3-50 in Section 3, “Administration”.

Direction

A tie line may be administered in one of the

three following ways:

●

Two-way (default): Calls may be made in either

direction.

●

Outgoing only: Calls may be made but not received.

●

Incoming only: Calls may be received but not made.

Type

●

There are four types of tie line options.

Wink start (default): The originating end of the tie line
transmits an off-hook signal and waits for the remote
end to send a signal indicating that it is ready (a wink).
This is also

●

Automatic start: Incoming calls are routed directly

know as

a dial repeating tie line.

to

an attendant station without a start signal. This is also
known as an automatic ringdown tie line.

●

Immediate start: No start dial signal is necessary.
Dialing may begin immediately following seizure of a
line. This is also known as a dial repeating tie line.

●

Delay dial start: The originating end of the tie line
transmits an off-hook signal and waits for the remote
end to send a delay dial signal (an off- hook signal
followed by an on-hook signal). This is also known

as

a dial repeating tie line.

Signaling Mode

Signaling mode designates the

electrical interface used.

●

E&M mode: The signaling leads are isolated from the

transmission leads. The E&M mode can be either
protected or unprotected.

WARNING:

The protected mode must be used
whenever the E&M leads extend out-of-building
and are not connected to the network interface.

Theory of Operation 1-47

●

Unprotected mode: Must be used for the E&M

Type 1 Standard interface in order to meet voltage

drop criteria for the interface. This mode is used
when there is a network interface.

●

Protected mode: Resistance is added in tie M lead

to provide additional protection from foreign
voltages and transients. This mode is used on local
tie lines, such as between systems in different
buildings.

●

Simplex mode: The signaling leads are superimposed

onto the analog transmission leads to provide a two­pair interface. Resistance is included in the signaling
leads for protection from foreign voltages and
transients. This mode is used primarily with E&M

Type 5 signaling on local tie lines.

Signaling Type

Signaling type designates the logical

signaling used. There are the following three options:

●

Type 1 Standard (default): The M leads are used for

signaling from PBX to line. Off-hook is -48 VDC and
on-hook is local ground. Signaling in the other
direction uses local ground for off-hook and open for
on-hook.

●

Type 1 Compatible: This interface is back-to-back

compatible with Type 1 Standard. It allows direct
connection between systems where no intermediate
signaling equipment is used.

●

Type 5: A symmetrical 2-wire arrangement that signals

in both directions by means of open for on-hook and
ground for off-hook. The primary application of Type­5 interface is local tie lincs.

1-48 Theory of Operation

Dialing Mode

This option sets the dialing mode for the

tie line.

●

Touch-Tone

●

Rotary (default)

Dial Tone

This option determines whether the dial tone
originates from the remote or local end of the tie line, or
both (you receive a second dial tone).

●

Remote (default)

●

Local

Answer Supervision Time

This option sets a time limit

in milliseconds (ms) for the remote station to signal the

calling station.

●

20 to 4800 ms (increments of 20 ms)

●

300 ms (default)

Tie Line Disconnect Time

This option sets a time limit

for the release of the E or M lead.

●

140 to 2400 ms (increments of 10 ms)

●

300 ms (default)

Your choice of signaling format (signaling mode and type)
depends on the particular application. Using Table 1-4
“Tie Line Preferred Signaling Formats,” you can
determine tie line compatibility between the MERLIN II
System and other systems.

Theory of Operation 1-49

TABLE 1-4 Tie Line Preferred Signaling Formats

Installation Situation

From

MERLIN II System

To

MERLIN II

Location

Same Site

MERLIN II System

Signaling

Mode and

Type

Simplex

Preferred Signaling Format

Protected

or

Unprotected

N/A

Signaling
Mode and

Type Unprotected

Simplex N/A

System or Inter- Type 5 Type 5

building

System 25

Same Site

System 75 or Inter-

Simplex N/A Simplex

Type 5 Type 5

building

System 85

Same Site
or Inter-

Simplex N/A

Type 5

Simplex

Type 5

building

Far End

Protected

or

N/A

N/A

Dimension

Same Site

PBX

Dimension Inter­PBX

Other

building

Same Site

E&M
Type 1
Compatible

E&M
Type 1
Compatible

E&M
Type 1
Compatible

Unprotected E&M Unprotected

Type 1

Standard

Protected

E&M Protected

Type 1

standard

Unprotected

E&M

Unprotected

Type 1

Standard

1-50 Theory of Operation

TABLE 1-4 Tie Line Preferred Signaling Formats (continued)

Insulation Situation

Preferred Signaling Format

From

MERLIN II System MERLIN II System

Signaling Protected Signaling
Mode and or

To

Location

Other Inter- E&M

Type Unprotected Type Unprotected

Protected

building Type 1

Compatible

Network
interface

…

E&M

Type 1

Unprotected Either

Standard

Far End

Protected

Mode and

E&M

or

Requires a

Type 1 protection

Standard

unit
Either

Theory of Operation 1-51

System Connectivity

This section describes typical hardware configurations for
a MERLIN II system with accessories and auxiliary
equipment Connectivity diagrams with descriptions are
provided for the following:

●

Simultaneous voice and data (analog station) using the
analog station module (408) to gain access to a remote
host computer.

●

Simultaneous voice and data (digital station) and local
host computer access using the digital station module
(008D).

●

Modem pool using the digital station module (008D)
and the basic telephone module (012).

●

Modem pool using the digital station module (008D)

SIMULTANEOUS VOICE AND DATA

and the analog station module (408).

●

Modem pool on dedocated outside lines for data-

●

Background music provided for callers through
Music-on-Hold.

●

External loudspeaker paging.

Simultaneous voice and data at an analog station allows
the user to connect to the system an analog voice terminal
and a data terminal or PC with data rates set by the
modem. This feature requires both an odd and even jack
to be connected to the voice terminal. Refer to the
connectivity diagram in Figure 1-12.

Simultaneous voice and data at a digital station allows the
user to have a digital voice terminal and a data terminal or
PC with data rates up to 19,200 bps between digital

1-52 System Connectivity

endpoints. Note that between the Modular Trunk Data

Module (MTDM) and the modem there can be a maximum
of 17 feet. Refer to the connectivity diagram, especially
Note 2, in Figure 1-13.

Remote

host

computer

Modem

Central

Office

Bridging

adapter

BR 241-B1

Even Station Odd

■ ■ ■

D8W
cord

Analog

voice

terminal

■ Line

Power
Supply

408 408 408 408 408

PFT

PFT

PFT

PFT

PFT

04

03
02
01

08
07
06
05
04
03
02
01

08
07
06

05

16
15
14
13
12
11
10
09

12
11
10
09

24
23

22
21
20
19
18
17

16
15
14
13

32
31
30
29
28
27
26
25

20
19
18

17

40

37
36
35
34
33

39
38

cord

See Notes 1

and 2

D8W
cord

D8AC

D4BU

Other

■

cord

■

VT

General

Purpose

Adapter
Tel Equip

■

cord

■

Line

Modem

2212C

Terminal

■

RS-232-C

(M25B)

MERLIN II System

Control unit

Notes:

1. Bridging adapter connects adjacent odd/even jacks (23, 24) to analog voice terminal.
This type of connection is required for features such as Voice Announcement to

Busy Telephone or Simultaneous Voice and Data.

2. Total distance between the control unit and the voice terminal cannot be more than
1000 feet without local power.

Data

terminal

or PC

FIGURE 1-12 Simultaneous voice and data (analog station).

System Connectivity 1-53

LOCAL HOST COMPUTER ACCESS

Local host computer access allows shared use of the host
computer through Modular Processor Data Modules
(MPDMs). The MPDMs may have different data rates or
the same rate, each set to a data rate of 19,200 bps or less.
Refer to the connectivity diagram in Figure 1-13.

MODEM POOLS

Connected to Basic

Telephone Jack

Connected to Analog
Station Jacks

Modem pools are groups of modems and associated
equipment used to convert digital data signals to analog
data signals or vice versa. Putting modems in pools makes

to

it easier for users

share a limited number of modems.
Each modem pool is used exclusively for either incoming
or outgoing calls.

The modem pool members use available basic telephone
jacks to send data between digital endpoints and remote

to

computers over MERLIN II system lines. Refer

in

connectivity diagram

Figure 1-14.

the

The modern pool members use available analog station

jacks to send data between digital endpoints and remote

computers over MERLIN II system lines. Refer to the

connectivity diagram in Figure 1-15.

Connected to
Dedicated Outside
Lines

1-54 System Connectivity

The modem pool members use dedicated outside lines to

send data betwecn digital endpoints and remote
computers. This type of modem pool would likely be used

if thcrc were many data calls to remote computers in order

II

to save the MERLIN

system lines for voice use. Refer

to the connectivity diagram in Figure 1-16.

Power

Supply

408 408 408 408 008D

PFT
04
03
02
01

08
07
06
05
04
03
02
01

MERLIN II System

control unit

PFT
08
07
06
05

16
15
14
13
12
11
10
09

PFT
12
11
10
09

24
23
22
21
20
19
18
17

PFT
16
15
14
13

32
31
30
29
28
27
26
25

D8W
cord

20
19
18
17

36

35

34
33

D8W

cord

PT 510D

Digital

voice

and data

See Note 2

MPDM

DCP

■

jack interface

MPDM

DCP

■

jack

MPDM

DCP

■

jack

MPDM

DCP

■

Jack

See Note 1

D8W

cord

PT 510D

Digital

voice

and data

DCE

DCE

interface

DCE

interface

DCE

interface

■

See Note 3

RS 232-C

(M25B)

■

■

■

D8W

cord

400B2 Adapter

D8W
cord

7406D with

Data Stand

See

Note 4

Data terminal

RS-232-C

or PC

■

■

■

computer

■

(M25B)

Local

host

D6AP
cord

KS-22911L1

Power supply

Notes:

1. The cable distance between the control unit and a MPDM, PT 510D, or 7406D
with data stand cannot be more than 1000 feet.

2. Some host computers act as DCE devices in which case the MPDMs will need to

be replaced with MTDMs or special wiring. If an MTDM can be used, the switch
settings are the same as an MPDM, but you don't need to set auto answer.

3. The cable distance between the MPDM or MTDM and the local host computer cannot

be more than 17 feet.

4. The cable distance between the 7406D and the data terminal cannot be more than

50 feet.

FIGURE 1-13 Simultaneous voice and data (digital station) and local host computer

access.

System Connectivity 1-55

Power
Supply

408 408 408 012 008D

PFT

PFT

PFT

36
35
34
33

16
15

14
13

04
03
02
01

08
07
06
05

12
11
10
09

D8W cord
1000' max.

Modem

pool

-------------------------------

08
07
06
05
04
03
02
01

16
15
14
13
12
11
10
09

24
23
22
21
20
19
18
17

32
31
30
29
28
27

26
25

MTDM

40
39
38
37

2212C

Modem

-------------------------------

D4BU cord
1000' max.

MTDM

RS-232-C

(M25B) 17 max.

2212C

Modem

MERLIN II System

control unit

FIGURE 1-14 Connectivity of a modem pool using a basic telephone module.

1-56 System Connectivity

Power
Supply

408 408 408 408 008D

PFT
08
07
06
05

16
15
14
13
12
11
10
09

PFT
12
11
10
09

24
23
22
21
20
19
18
17

PFT
04
03
02
01

08
07
06
05
04
03
02
01

MERLIN II System

control unit

PFT
16
15
14
13

32
31
30
29
28
27

26
25

20
19

18
17

36
35
34
33

D8W cord

----------------------------

Telephone

and Modem

Interface 2

Modem pool

MTDM

2212C
Modem

Basic

MTDM

RS-232-C (M25B)

17' max.
2212C

Modem

D4BU cord

Basic

Telephone

and Modem

Interface 2

-----------------------------

D8W cord

1000’ max.

FIGURE 1-15 Connectivity of a modern pool using an analog station module.

System Connectivity 1-57

Power
Supply

408 408 408 408 008D

PFT

PFT
08
07
06
05

PFT
12
11
10
09

16
15
14
13

20
19
18
17

PFT
04
03
02
01

RS-232-C (M25B)

17’ max.

/

/

2212C
Modem

2212C
Modem

Central Office

08
07
06
05
04
03
02
01

16
15
14
13
12
11
10
09

24
23
22
21
20
19
18
17

32
31
30
29
28
27
26
25

36
35

34
33

D8W cord
1000' max.

--------------------------

MTDM

MTDM

----------------------

Modem pool

MERLIN II System

control unit

FIGURE 1-16 Connectivity of a modern pool on dedicated outside lines.

GENERAL REQUIREMENTS FOR MODEMS

Modems are an essential part of MERLIN II system
features involving local and remote computer access. Any
modem other than the 2212C used with system hardware
should meet the following requirements to ensure proper
operation under all conditions. Modem requirements
differ according to applications. When planning the
system, remember the various modem configurations such
as a single modem for analog voice/data or modem pools.
The planning information recorded on the individual
Station Configuration forms should reflect the exact
modem arrangement for each station.

D4BU to

line jack

1-58 System Connectivity

The following paragraphs describe the basic requirements

for any modem, and specific requirements when used in
outgoing and incoming modem pools.

Basic Requirements

for Modems

NOTE:

Modems

can meet these requirements through

fixed features or through hardware and software
options that can be set. An option setting may
make a modem appropriate for one pool in the
MERLIN II system but not another.

The basic-requirements for modems are the following:

Full-duplex operation, for switched networks

●

A single speed between 300 bps and 19,200 bps

●

●

Serial transmission of characters in a binary
asynchronous format

●

EIA RS-232-C interface
Peak signal level compatible with the MERLIN II

system
Modular jack connection for telephone network

●

Requirements for
Outgoing Modem
Pools

●

Loss of earner disconnect so that the modem goes on­hook and turns received line signal detector, EIA lead

RLS (carrier on) off
Disconnect if EIA lead DTR (data terminal ready) goes

●

off

●

Passing of break character and long space signal
Saving of options during power outage

●

In addition to meeting the basic requirements, a modem
used for outgoing calls must have the following
characteristics:

System Connectivity 1-59

●

Touch-Tone dialer that can pause and dial characters 0

through 9, #, and *

●

Detection of dial tone

●

Ability

to take terminal dialing instructions

(compatible parity and character length with the
MTDM)

●

EIA (RS 232-C) lead DSR and RLS on before a call is

placed (follows DTR)

Requirements for

Incoming Modem

Pools

MUSIC-ON-HOLD

EXTERNAL LOUDSPEAKER PAGING

In addition to meeting the basic requirements, a modem
used for incoming calls must have the following
characteristics:

●

Auto-answer feature

●

Compatible parity and character length with MTDM

Music-on-Hold provides background music for callers

who have been placed on hold. It requires the use of a

music coupler. You must reserve a line jack for a music

source such as a radio, tape player, or stereo system. To
make it easier to add outside lines in the future, use the
last line jack(s) on the rightmost line module for the
Music-on-Hold connection. Refer to the connectivity

diagram in Figure 1-17.

Refer to the connectivity diagram in Figure 1-18. External

loudspeaker paging allows you to connect a single or
multizone paging system through a line jack on the
MERLIN II system. Background music can also be
provided by connecting a music coupler and a music

source.

1-60 System Connectivity

Speaker

8-Ohm wire

J5

Power
Supply

408 408 408 408 408

PFT
04
03
02
01

08
07
06
05
04
03
02
01

PFT
08
07
06
05

16
15
14
13
12
11
10
09

PFT
12
11
10
09

24
23
22
21
20
19
18
17

PFT
16
15
14
13

32
31
30
29
28
27
26
25

PFT

20

19
18

17

40
39
38
37
36
35
34
33

(Paging)

(Music)

D4BU cords

4BU cord

103A

connecting

block

12345678

103A

connecting

block

12345678

(Page input)

J1

Page Pac 20

Powermate

Music In

13
14

15

4PT
5PR

Loop

start

trunk

adapter

29R
30T

PBX

26

J2

27

MERLIN II System

control unit

AC line cord

Auxiliary

■

output

■

Music Out

Music

coupler

Background music

117 VAC

●

■

source

Standard

patch cord

Standard phonograph patch cord

FIGURE1-17 Connectivity of single-zone paging with Music-on-Hold.

124v

source

GND

Power

supply

Music

System Connectivity 1-6

Power
Supply

408 408 408 408 408

D4BU

cord

●

Page
input

J1
P1

Page

input

Music in

Switch

CK LS
DL GS

Page Pac 20

Powermate

Common control

unit

PFT

PFT

PFT

08

04
03
02
01

08
07
06
05
04
03
02
01

07
06
05

16
15
14
13
12
11
10
09

12
11
10
09

24
23
22
21
20
19
18
17

MERLIN II System

control unit

PFT
16
15
14
13

32
31
30
29
28
27
26
25

PFT

20

19
18

17

40
39
38
37
36
35
34
33

Page

port

Music

port

D4BU

cord

D4BU
cord

ooooooooo

Speaker

Speaker

Speaker

BKGND

●

Music
coupler

Music out

Music in

Standard

phonograph

patch cords

Music
source

FIGURE 1-18 Connectivity of multizone paging with background music and

Music-on-Hold.

1-62 System Connectivity

Section 2: installation

Preinstallation Requirements

Reviewing the Planning Forms
Environmental Requirements
Spare and Location Requirements
Power Requirements and Secifications

Grounding Requirements
Wire Length Limitations
Wall Attachment Requirements

System Grounding Requirements

System Ground Connection
AC Outlet Tests
CO Line Protector
Surge Protectors

IROB Protectors
Static Discharg

Radio-Frequency Interference

e Problems

2-1
2-1

2-1
2-2
2-2

2-3
2-3
2-4

2-5
2-5

2-7
2-8
2-8
2-9
2-9
2-9

Wiring the System

Typical MERLIN II System Wiring
Module Jacks

Outside Line Wiring
Preparing the Network Interface
Testing the Outside Lines
Connecting Outside Lines to the Control Unit
Tie Line Module Wiring

Voice Terminal Wiring
Connecting Voice Terminal Wiring to the Control Unit

Wiring a Voice Terminal for Two Voice-Pairs

Standard 4-Pair Wiring

2-12

2-30

2-12
2-14

2-17
2-17
2-19
2-19
2-21

2-23
2-23
2-27

Jack Field Wiring
Constructing a Jack Field for Voice Terminal Wiring
Connecting Voice TerminaI Wiring to a Jack Field

2-33
2-35
2-37

Extending the Network Interface to a Jack Fieid

for Outside Lines

2-41

Wiring Reference Tables

Installing the Control Unit

Control Unit Components
Mounting the Basic Carrier

Mounting the Expansion Carrier
Determining Unit Load Requirements

De

termining Module Slot Assignments

Module Installation
Installing a Module
Removing a Module
Insralling the Power Supply Module

Installing the Auxiliary Power Unit
Installing the Feature Module on the Processor Module
Installing Line and Station Modules
Connecting a Printer to the ControI Unit
Connecting the Control Unit to an AC Outlet

Power to the System

2-45

2-50

2-50
2-52
2-56
2-57

2-61
2-62

2-63
2-64
2-66

2-72
2-73
2-79
2-81
2-90
2-90

Connecting the Voice Terminals

Assembling the Voice Terminals
Connecting Voice Terminals to the System
Testing the Voice Terminals

Labeling Each Voice Terminal
Connecting the Power Failure Telephone
Testing the PFT Jacks

2-92
2-93

2-95

2-95
2-96
2-97
2-99

Testing the System

2-100

Testing the Voice Terminal Jacks for a Dial Tone
Testing Intercom Calls
Testing Outside Lines
Testing Tie Lines

Completing the Installation
Attaching the Control Unit Covers

Modifying the System

Adding an Outside Line
Adding a Voice Terminal
Moving a Voice Terminal

Adding Accessories

General Accessories

Power Accessories

2-100

2-101
2-103
2-104

2-106
2-106

2-112

2-112
2-113
2-115

2-117

2-117
2-122

Upgrading an Existing System

Site Preparation
Get a Printout of the Existing System
Upgrade Instructions FMl or FM2 to R3

Upgrade Instructions FMl to FM2

2-131

2-131
2-132
2-133
2-136

Preinstallation Requirements

REVIEWING THE PLANNING FORMS

Review the completed system planning forms, which

should be on site, before starting installation. The forms

for Release 3 are titled:

●

Form la, System Form—Incoming Lines

●

Form 1b, System Form—Tie Lines

●

Form 1c, System Form—Module Identification

Diagram

●

Form 1d, System Form—Station Planning

●

Form 1e, System Form—Requirements and Options

The forms for Feature Modules 1 and 2 are titled:

●

Master Planning Form

●

System Configuration Form

You should be familiar with the entire layout of the system
including wiring, jack field, network interface, and
accessory requirements. If the system has data hardware,
see the separate manual,

System Data Communications Guide,

MERLIN II Communications

for complete

instructions for installing data equipment.

ENVIRONMENTAL REQUIREMENTS

The control unit should be operated in an environment that

meets the following conditions.

●

Operating temperatures.

should be 40 to 1040F (4 to 400C). Optimum
operating temperature is 60

●

Humidity.

The humidity should be between 20 and 80

The operating temperature

0

F.

percent.

●

Airborne contamination.

Do not expose the control

unit to moisture, corrosive gas, dust, chemicals, spray
paint, or similar material.

Preinstallation Requirements 2-1

WARNING:

outdoors.

The control unit cannot be installed

It

must be installed in an environment
suitable for electronic equipment. Do not expose the
control unit to devices that generate electrical

interference such as arc welders or motors.

SPACE AND
LOCATION
REQUIRIEMENTS

The control unit should be located with the following

points in mind:

●

CO line protection.

The control unit should be
installed near the Central Office line protectors
provided by the local telephone company. Refer to

“System Grounding Requirements” on page 2-5 for
additional information about line protection.

Ventilation.

●

Allow at least 1 inch of space on the right
and left sides of the control unit and 12 inches of space
above and below the control unit to prevent
overheating. Do not place the control unit near
extreme heat or in direct sunlight.

Placement.

●

AIlow at least 1 foot of space to the right
of the basic carrier for expansion and at least two feet
of space to the left for a jack field. Refer to “Wiring
the System” on page 2-12 and “Jack Field Wiring” on
page 2-33 for additional information on space
requirements.

POWER REQUIREMENTS SPECIFICATIONS

Listed below are the power requirements and
specifications for the control unit:

●

Voltage range.

Voltages generated by the power supply remain within
specification for an
The system will bridge a 40 millisecond supply outage
without dc voltages being affected.

2-2 Preinstallation Requirements

99 to 129 VAC

ac

line voltage low of 99 VAC.

●

Frequency range.

●

Max. current.

●

Max. power use.

60 Hz +/- 1 percent

3 amperes per power supply

225 watts per power supply

GROUNDING REQUIREMENTS

WIRE LENGTH

LIMITATIONS

The system must be connected to a properly grounded ac
outlet. See page 2-5, “System Grounding Requirements,”
for more information.

NOTE:

If Modular Processor Data Modules, Modular

Trunk Data Modules, or moderns are to be
installed at the control unit location, additional
grounded ac outlets will be needed.

Wires connected to the control unit should consist of a
single continuous run, i.e., without extension cords or
other splices, and should meet these specifications:

Power cord. The power cord must be less than 6 feet,
and must be connected to a properly grounded ac
outlet that is not switch-controlled.

Incoming lines. The distance from the network
interface provided by the local telephone company for
incoming lines must be spanned within one cord length
(generally 25 feet or less).

Jack field. The distance to the jack field mounted to
the left of the earner must be

Station. Each voice terminal

must be within 1000 feet

of the control unit.

WARNING: If a voice terminal is used for In-Range,
Out-of-Building (IROB) applications, IROB
protectors are required. See “IROB Protectors” on
page 2-126 for more information.

Preinstallation Requirements 2-3

WALL ATTACHMENT REQUIREMENTS

The customer should have a backboard mounted at the
control unit site. If one is not in place, you may need to
attach a backboard to the wall. The backboard should
meet these specifications:

●

It should be made of 3/4-inch thick plywood.

●

It should be 4 feet wide by 2 feet high in order to

accommodate a basic control unit with an expansion
carrier and jack field. If ample wall space is available,
use a backboard that is 4 feet by 4 feet, regardless of
the system’s size. This size provides enough space for
future expansion.

●

It should be attached to the wall with hardware that has

a combined pull-out force of at least 500 pounds.

Determine the type of mounting surface on which the
board is to be mounted, and refer to Table 2-1 for
recommended hardware.

TABLE 2-1 Backboard Mounting Hardware

Mounting surface:

Wood
Concrete

Hardware required:

Wood screws

Masonry anchors

Brick
Cinder block

Plaster

Toggle bolts

Plasterboard

Sheet metal

Sheet metal screws

2-4 Preinstallation Requirements

System Grounding Requirements

Proper grounding of the installation site is fundamental to

SYSTEM GROUND CONNECTION

protect the MERLIN

II

communications system against

these types of electrical discharges:

●

Lightning strikes near the

●

Power surges

●

Power crosses on Central

●

Static discharge

The following procedures serve as electrical safety
requirements and guidelines in grounding. Apply them as
you install the MERLIN II system.

WARNING:

Make sure these requirements are satisfied

before applying power to the system.

The control unit the CO line protector, and the ac power
service panel should be as close to each other as possible.
The adequacy of lightning protection is a direct function
of the distance between these pieces of equipment.

Recognizing that equipment may be spread throughout a
building, the National Electric Code (NEC) requires that
the ground point for the CO line protector be bonded to the
ac power ground. Proper grounding helps prevent
equipment damage due to lightning energy and/or power
transients conducted into the equipment via CO and ac
power lines.

It is the responsibility of the local telephone company to
provide protection of Central Office lines at the entrance

to the site. The protection should consist of the following:

●

Carbon blocks or gas discharge tubes connected to an
approved ground

System Grounding Requirements 2-5

●

Adequate bonding of the Central Office line protector

ground and the power company ground

To

Central

Office

CO

lines

CO

line

protector

●

Refer to Figure 2-1 for an example of a typicaI MERLIN

II

system grounding plan.

MERLIN II System

control unit

Power
Supply

--

408 408 408 408

AC

surge

suppressor

outlet

Shield
ground

Earth

ground

Bond wire

Plug

Power

ground

rod

FIGURE 2-1 A typical MERLIN II system grounding plan.

2-6 System Grounding Requirements

AC

B
W

GND(Green)

Commercial

power

●

Power
service

●

●

●

AC OUTLET TESTS

The following tests verify proper grounding of the ac

outlet.

WARNING:

Hazardous voltages are present during the

following tests. Use great care when working with ac

power line voltages.

Check the ac outlet for proper ground with a circuit tester.

NOTE:

You may use any generic unit (such as the Ideal

61-035 Circuit Tester) to verify that the outlet is
wired properly.

1 Plug an Ideal or equivalent circuit tester into the outlet

to be tested. If the circuit is properly grounded, the
yellow and white lights on the tester will light.

2 Remove the circuit tester and, if necessary, test another

outlet.

NOTE:

If the ac outlet test shows an improper ground, do

not

install the MERLIN II system. Tell the

customer to have an electrician correct the

problem.

Check the ac outlet for proper ground with a Volt-Ohm­Milliammeter (VOM).

1

Set the VOM to the scale on which you can read 115

VAC.

2 Measure the ac outlet voltages:

> Hot to third-wire ground should be about 115

VAC.

> Neutral to third-wire ground should be less than

2.5 VAC.

3 If the voltage readings do not measure the values

suggested, the ac outlet is improperly wired. Notify
the customer that an electrician should repair the
outlet.

System Grounding Requirements 2-7

CO LINE PROTECTOR

The following test can be used to check CO line protector

not

grounding. This test does

check the bond between the
power company and telephone company protector
grounds.

1 Connect a craft test set between the protector ground

lug and the ring side of the CO line.
2 If a dial tone is present, the protector is grounded.
3 If a dial tone is not present, the protector is not

grounded; call the local telephone company. Request
that they properly-ground and bond the CO line

protector to ac power ground.

SURGE PROTECTORS

If the CO line protector is properly grounded and bonded
to the ac power ground, most lightning damage will be
prevented.

Both the ac line and CO line parts of the 147A Protector
are available as separate units. The ac line component is
available as the 145A AC Surge Protector. For installation
instructions, refer to CIB 3110, which is included with the
component. The central office line component is available
as the 146A CO Line Protector. Installation instructions
for the 146A CO Line Protector are available in CIB 3111,
which is included with the device.

A 147A Protector provides additional protection from ac
and CO line power surges. If the line module’s apparatus
code contains the letter “A” (517A1, 517A2, or 517A4),
use the 147A Protector for surge protection. If the line
module’s apparatus code contains the letter “B” (517B1,
517B2, or 51734), use a 145A Protector. Modules with
the “B” designation have CO line protection built in, but
not ac line protection.

For installation and user instructions, refer to Customer
Instruction Booklet (CIB) 3109, which is included with
the 147A Protector.

2-8 System Grounding Requirements

IROB PROTECTORS

Equipment that is connected to the analog station jacks
(408/008) and is located in a building outside of the main

(control unit location) building, but within 1000 feet of the
control unit is called In-Range, Out-of-Building (IROB)
equipment. To protect both the control unit and the IROB
equipment from exposure to lightning, inadvertent contact
with power lines, and power currents induced by nearby
power lines, IROB Protectors are required. Two TII
Model M343 IROB protectors are required for every analog
station jack that is connected to IROB equipment. The
IROB protectors must be located at the cable entrance/exit
of both buildings. See “IROB Protectors” on page 2-126
for more information.

TIE LINE
PROTECTION

STATIC DISCHARGE PROBLEMS

Local tie lines that extend out-of-building must have
primary protection in the form of voltage limiters
(typically carbon blocks or gas tubes). A protector should
be provided in each building where the wiring run leaves
or enters.

The MERLIN II system contains components that can be

damaged by electrostatic discharge. To prevent static

discharge, take these precautions:
1 Properly ground yourself when replacing modules or

performing other tasks on the control unit.

2 Have the customer maintain relative humidity between

20 and 80 percent.

3 Have the customer install an antistatic mat at each

voice terminal.

RADIO-FREQUENCY

INTERFERENCE

In most cases, radio-frequency interference (RFI), or
electrical noise, is introduced to the system through trunk
or voice terminal cables. However, electromagnetic fields
near the control unit may also cause RFI in the system.
Therefore, the control unit and cable runs should not be

System Grounding Requirements 2-9

placed in areas where a high electromagnetic field
strength exists. Leading causes of interference include
AM and FM radio station transmitters, television station

transmitters, induction heaters, and motors (with
commutators) of 0.25 horsepower (200 watts) or greater.
Small tools with universal motors are generally not a

problem when they operate on separate power lines.
Motors without commutators generally do not cause

interference.

Field strengths below 2 volts per meter are unlikely to
cause interference. Field strength can be measured by a
tunable meter such as the Model R-70 meter manufactured

by Electro-Metrics Division, or broadband meters such as
the HOLADAY™ HI-3001 meter or Model EFS-1 meter
manufactured by Instruments for Industry, Inc.

You can estimate the field strength produced by radio

transmitters by dividing the square root of the emitted

power in kilowatts by the distance from the atenna in

kilometers. The result yields the approximate field

strength in volts per meter and is relatively accurate for

distances greater than about half a wavelength (150 meters

for a frequency of 1000 KHz).

Solutions to Radio-

Frequency

Interference Problems

To reduce or eliminate radio-frequency interference

problems from nearby induction heaters or 0.25

horsepower motors, either move the equipment causing

the problem or move the MERLIN II system control unit

to a different location.

To reduce or eliminate radio-frequency interference

problems from nearby radio station antennas, choose from

among the following solutions:

●

Do not run MERLIN II system station wire in the same

conduit as ac cable, or next to ac circuits if the station
wire is exposed. If possible, do not cross station wire

2-10 System Grounding Requirements

over ac circuit wire. When crossing station wire over
ac circuits is unavoidable, try to maintain a 3-foot
clearance.

●

Use conduit for wiring runs whenever possible. Be
sure that the conduit is grounded. If the conduit is not
grounded, run a No. 12 wire from the conduit and
terminate it on the ac earth ground, or bond it to the
earth ground.

●

Run station wire on the baseboard or as close to the

floor as possible.

●

Run shielded wire for the stations that are having

interference problems. Ground the shield of the wire

and bond it to the ac ground.

●

Visually verify that the ac power line is grounded and

that it is bonded to the protector ground. Use an Ideal

circuit tester (or equivalent) or a VOM to verify that

the ac outlet is grounded. (See “AC Outlet Tests” on

page 2-7.) If the outlet is not grounded, run a No. 12

wire from either the grounding terminal or the center

screw of the ac outlet to the location where the ac

power line is earth grounded, and terminate it.
Install Built-in speakerphone stations (BIS-10, INS-22,

BIS-34).

●

Install a Z200A filter at the MERLIN II system station.

If interference is still present, install another Z200A

filter at the control unit.

●

If there is radio interference on the CO lines, use a

ZIOOA filter.

Change the ac outlet to a different branch circuit.

●

●

Move the control unit to a different location.

System Grounding Requirements 2-11

Wiring the System

TYPICAL MERLIN II

SYSTEM WIRING

Figure 2-2 illustrates typical MERLIN II system wiring.

Central office lines enter the site through a 25-pair cable.
The network interface in this example is a 66-type block
configured as an RJ21-X-type connector. From the
network interface, a DIW cable takes the 25 lines to a jack
field for outside lines. The jack field interfaces the
outside line wiring with D2R cords that plug into the line
jacks on the control unit modules. At this point, outside
lines are connected to the control unit.

The station side of the control unit goes to a jack field for
voice terminals through D8W cords. The other side of the
jack field goes to the 102A connecting blocks through 4­pair DIW cable. The voice terminals plug directly into the
connecting blocks through four-pair modular cords.

2-12 Wiring the System

Central

office

lines

25 Pair cable

RJ21-X

interface

DIW cable

(Jack field

for outside lines)

Z122C Box

With

Z610A

Adapters

D2R cords

Power

Supply

408 408 408 408 408

PFT
04
03
02
01

08
07
06
05
04
03
02
01

PFT
08
07
06
05

16
15
14
13
12
11
10
09

PFT
12
11
10
09

24
23
22
21
20
19
18
17

PFT
16
15
14
13

32
31
30
29
28
27
26
25

MERLIN II System control unit

PFT

20
19
18
17

40
39
38
37
36
35
34
33

D8W

cords

(Jack field

for voice

terminais)

Z122C Box
with Z610A

adapters

Outside

lines

4-Pair

DIW cords

Station

lines

102A

D8W cord

Voice

terminal

Office 1

102A

D8W cord

Voice

terminal

Office 2

102A

D8W cord

Voice

terminal

Office 3

FIGURE 2-2 Typical MERLIN II system wiring installation.

102A

D8W cord

Voice

terminal

Office 4

Wiring the System 2-13

MODULE JACKS

There are various types of jacks on the line and station
modules (Figure 2-3). Each type of jack has a specific
function as follows:

●

Analog station jacks.

These jacks are for analog

voice terminals, analog data devices, and accessories.

●

Basic telephone jacks.

These jacks are for basic
telephones with Touch-Tone or rotary dial capability.
Do not connect MERLIN II system analog voice
terminals to basic telephone jacks.

●

Digital station jacks.

These jacks are for digital voice
terminals, digital voice/data sets, MPDMs, MTDMs,
etc.

●

Outside line jacks.

These jacks are for outside lines
provided by the local telephone company. You can
also connect an optional loudspeaker paging device
and/or music source to any of these jacks.

●

Power Failure Telephone (PFT) jacks.

These jacks
are for basic telephones only. In case of a power
outage, basic telephones plugged into these jacks
become operational. They do so by bridging onto the

lowest line of the group of four line jacks with which

not

they are associated. Do

use MERLIN II system

voice terminals as power failure telephones.

Tie line jacks.

These jacks are for a transmission
facility dedicated to interconnect two private switching
systems.

2-14 Wiring the System

PFT jack

400EM

Switch

Tie line

jacks

Tie line

jacks

Switch

408

Outside Iine

jacks

Analog station

FIGURE 2-3 Line and station module jacks.

jacks

Analog station

jacks

008

Wiring the System 2-15

PFT jack

Outside iine

jacks

400 w/DTMF

Outside line

jacks

PFT jack

Outside line

jacks

PFT jack

800

Outside line

jacks

Basic

telephone

jacks

012

008D

FIGURE 2-3 line and station module jacks (continued).

2-16 Wiring the System

Digital station

jacks

Outside Line Wiring

PREPARING THE NETWORK INTERFACE

The local telephone company provides the telephone
numbers for outside lines, as well as an installed network
interface that may consist of 1-Line adapters (RJ11-type),
2-line adapters (RJ14-type), or 25-line (50-pin, RJ21-type)
connectors.

You can connect the outside lines from the network
interface connector to the control unit using D2R cords.
The method used to connect the outside lines to the
control unit depends on the type of network interface as
follows:

●

1-line adapter (RJ1l-type). This adapter allows one
connector for each outside line.

> Label each jack with the telephone number.

● 2-line adapter (RJ14-type). This adapter connects

two outside lines per jack.

> Label each jack with the telephone numbers of its

two outside lines.

>

Plug a 2-line adapter (267C-type) into each jack.

●

50-pin connector (RJ21-type). This connector carries

up to 25 lines.
>

Label the interface with the numbers for the
outside lines.

>

To extend the network interface to the jack field,
refer to the instructions in “Jack Field Wiring” on
page 2-33.

Refer to Figure 2-4 for examples of network interfaces and
adapters.

Wiring the System 2-17

Single-line

adapter (RJ11)

2-Line adapter

(RJ14)

66-Type block (RJ21-type) 25 line interface

Line 1

Line

2

Line 3

Line 4

(267C)

Line Tip Ring Phone Number

1 1
2 2 27
3 3 28 555-3829

● ● ● ●●●

● ● ● ●●●

25 25 50 555-3851

26

555-3827
555-3828

Line 5

Line 6

Line 25

FIGURE 2-4 Network interface adapters.

2-18 Wiring the System

TESTING THE

OUTSIDE LINES

You often need to test an outside line at the network
interface or jack field. This test will verify that the outside
telephone lines are working properly. To perform this test,
you-need a basic rotary dial telephone and a Touch-Tone
telephone, each with a modular cord, or two craft sets.

CAUTION:

Do not use a MERLIN II system voice

terminal for testing. It does not work for this test, and it
can be damaged if you use it for this purpose.

1

Bring the Basic telephones or craft set to the jacks for
the outside lines (either at the network interface or at
the jack field).

2

Plug the telephone’s modular cord or the craft set’s
cord into an outside line jack and listen for a dial tone.

3

Dial a known telephone number with each basic
telephone or the craft set to verify both rotary and
Touch-Tone dialing.

4

Call each outside line jack with a basic telephone or
craft set to verify ringing.

5

Repeat steps 2 through 4 for each outside line.

CONNECTING

OUTSIDE LINES TO

THE CONTROL UNIT

You need the following items to connect the control unit
to the jacks for the outside lines, whether they appear at
the jack field or at the network interface.

●

Outside line numbers label. This label is for listing
each outside line number connected to the system with
its corresponding jack number. The label is packed
with the installation kit and it should be pasted on the
inside front cover of the control unit or the inside of
the left door of the jack field box containing the

outside lines.

Wiring the System 2-19

●

Single-pair modular line cords.

You need one D2R

cord for each outside line. The cord must be long

enough to reach the network interface.

●

Green line-cord labels.

These labels are marked 01,
02, 03, etc. You need a matching pair for each line
cord.

●

Outside line numbering strips.

These labels are used

to number all the line jacks on the modules themselves.

You can have up to 56 outside line jacks with the
MERLIN II system. The numbering sequence is 01 to 56.

To connect the outside line wiring, follow these steps:

1 Review Form 1a, System Form-lncoming Lines for

Release 3, or the Master Planning Form for Feature
Modules 1 and 2, to determine each outside line
assignment on the control unit.

The outside line numbers are the telephone numbers
listed at the network interface or inside the left door of
the box in the jack field containing the jacks for your
outside lines.

2 Number sequentially from 01 to 56 every outside line

jack on the modules using the outside line numbering

strips. Begin with the module in slot 1, numbering
from bottom to top and working from left to right
across the control unit (See Figure 2-2 on page 2-13
for the numbering sequence.)

Refer to Figure 2-3 on pages 2-15 and 2-16 to identify

those modules that have line jacks and locate the

-

positions the line jacks occupy on those modules.

3 Connect the outside line jacks on the modules to the

network interface using D2R cords. Thread the wires
through the wire managers at the base of each module
as you connect the wires to the jacks. Label each end
of each cord with the outside line jack number to
which each is connected.

2-20 Wiring the System

4 Write the telephone number assigned to each of the

line jacks next to the number for that line jack on the
outside line numbers label found on the inside of the
control unit’s front cover or on the inside of the left
door of the jack field box containing the outside lines.

TIE LINE MODULE

WIRING

WARNING:

National and local building codes specify

the type of cable required for telecommunication
wiring. For example, indoor wiring (DIW) cannot be
used inside or on top of air plenums or ducts, along hot
pipes; or across walkways. Consult your local
ordinances and regulations for proper cable selection.

If staples are used to attach the cords to walls or
baseboards, check that the cords have not been pierced.
Also, do not run Central Office lines from the network
interface to the control unit if the distance if greater
than 25 feet.

The interface from the Tie Line Module to the network
facility is provided through modular jacks. Each modular
jack provides an electrical interface to the network that
consists of six leads: T (pin 5) and R (pin 4) are for
outgoing analog transmission; T1 (pin 1) and R1 (pin 2)
are for incoming analog transmission; and E (pin 3) and M
(pin 6) are for signaling. Figure 2-5 shows how to connect
the Tie Line Module to the network interface.

WARNING:

The protected mode must be used
whenever the E&M leads extend out-of-building and
are not connected to the network interface. See pages
1-47 and 1-48.

Wiring the System 2-21

Power
Supply

MERLIN II System

control unit

408 408 408 408 400

EM

D8W

cord

25 pair

cable

T (5)

RJ2GX

26 T

R (4) 1

Z601A

Adapter

T1 (1)

R1 (2)

E (3)

27

28

M (6) 3 M

Z601A - Adapter

Jack Position Connector Position

1 3
24
35
42
51
66
77
88

R
T1

2

R1

E

To

Network

and

Facility

Signaling

Equipment

Power
Supply

408 012 DCP 408 400

EM

D8W cord

D8W cord

D8W cord
D8W cord

MERLIN II System

control unit

FIGURE 2-5 Tie Line Module wiring.

356A

Adapter

25 pair

cable

T (5)
R (4)

T1 (1)
R1 (2)

E (3)
M (6)

RJ2GX

26 T

1R

27 T1

2 R1

28 E

3M

To

Network

and

Facility

Signaling

Equipment

2-22 Wiring the System

Voice Terminal Wiring

CONNECTlNG VOICE
TERMINAL WIRING
TO THE CONTROL

UNIT

You can connect up to 120 station jacks, which support up
to 120 voice terminals in the MERLIN II system.

NOTE:

The terms “voice terminal” and “station” are

synonymous when describing the wiring and
labeling of the voice terminal side of the
MERLIN II system.

Up to 60 stations can be connected with the Voice

Announcement to Busy Voice Terminal or Simultaneous
Voice and Data features. Both of these features require
the use of two adjacent odd/even jacks on the control unit
for each station that is connected with the feature.
Because they require two voice-pair wiring, use of either
of these features decreases the system’s voice terminal
capacity. See “Wiring a Voice Terminal for Two Voice-

Pairs” on page 2-27.

NOTE:

The default intercom numbers (10 through 69 and
700 through 759) should not be confused with the
station jack numbers (01 through 120) that
identify the sequential station jack locations on
the modules. Intercom 10, for example, is
located in the first station jack on the first station
module of the control unit, labeled 01. The
“odd/even” in this type of wiring refers to jack

not

numbers,

intercom numbers.

You can connect the voice terminal locations either

directly, with modular voice terminal cords, or through
building wiring to a jack field at the control unit location.

Jack field wiring is the recommended method for
installations with more than 30 stations. Direct
connection is recommended for installations with fewer
than 30 stations. Determine which method to use to
connect the voice terminal wiring to the control unit and
follow the appropriate instructions below under
“Connecting Voice Terminal Wiring Through a Jack
Field” or “Connecting Voice Terminal Wiring Directly.”

Wiring the System 2-23

Refer to “Jack Field Wiring” on page 2-33 for instructions
on how to construct a jack field. You need the following

items to complete the connections:

●

System directory label.

Use this label to record the

end locations of each intercom number in the system.

●

Blue station-cord labels.

These labels come in pairs
with the basic and expansion carrier and are used to
identify cable runs. The first sheet of labels is
numbered 01 through 69 and is shipped with the basic

carrier. The second sheet is numbered 70 through 120
and 700-759. This sheet is packed with the expansion
carrier. You should have a matched pair of labels for
each line cord.

●

4-Pair modular jumper cords.

These cords are for
jack field connections. You should have one cord for
each voice terminal in your system.

●

System Labels.

These labels, used to number jacks,
are shipped with the feature module. They are
numbered 1 through 56 for lines and 01 through 120

for stations.

Connecting Voice
Terminal Wiring
Through a Jack Field

●

Line Cable Numbering Labels.

These green labels

come in pairs and are numbered 01 through 56.

To connect the station wiring through a jack field, perform
the following steps:

1 Number every station jack on the modules sequentially

from 01 through 120, using the station numbering

strips. Begin with the module in slot 1, and number
from bottom to top, then continue from left to right
across the control unit (See Figure 2-2 on page 2-13.)

You may want to review Figure 2-3 on pages 2-15 and
2-16 to identify which modules have station jacks and
locate the positions of the station jacks on each
module.

2-24 Wiring the System

2 Wire the station jacks on the modules to the jack field

using D8W cords. Thread the wires through the wire
manager located at the base of each module as you
connect them to the station jacks. Label each end of
each wire with the intercom number to which it
connects. Remember, the intercom numbers do not
necessarily match the jack numbers. Intercom 10, for
example, is connected to station jack 01 on the first
station module of the control unit.

3 Record the end location of each intercom number on

the system directory label and put this label on the
inside of the front cover of the control unit.

Complete wiring instructions for data stations are found in
the separate document,

MERLIN II Communications

System Data Communications Guide.

Connecting Voice

Terminal Wiring

Directly

To connect the voice terminal locations directly to the
control unit, perform the following steps:

1 Number every station jack on the modules sequentially

from 01 through 120, using the station numbering
strips. Begin with the module in slot 1 and number
from bottom to top; then go on to the next module with
station jacks, working from left to right across the
control unit modules.

You may want to review Figure 2-3 on pages 2-15 and
2-16 to identify which modules have station jacks and
locate the positions of the station jacks on each
module.

2 In the system directory, fill in the voice terminal

location you have selected for each intercom number.

Wiring the System

2-25

3 Beginning with a pair of labels marked 01, label each

cord at both ends with matching labels.

If the distance between a voice terminal location and
the control unit requires the use of extension cords,
label each end of the wiring run. Attach one label near
the plug to the voice terminal and the matching label
near the plug to the control unit.

4 Run cords from the voice terminal locations to the

control unit.

CAUTION:

Do not run cords inside air plenums or

ducts, along hot pipes, or across walkways. If you
use staples to attach cords to walls or baseboards,
be careful not to pierce the cords. If there are one
or more In-Range Out-of-Building voice terminals
to be installed, be sure to use two IROB protector
for each lROB voice terminal.

5 Thread each cord through the wire manager of the

control unit and up to the voice terminal jack with the
same number as the cord label, and plug it in. For
Release 3, refer to Form 1d System Form-Station
Planning; for Feature Module 1 or 2, refer to the
Master Planning Form to check the intercom number
assignments against the voice terminal jack locations.
Intercom 10, for example, is connected to the voice
terminal jack labeled 01 at the first jack location of the

first station module in the control unit.

2-26 Wiring the System

WIRING A VOICE TERMINAL FOR TWO VOICE-PAIRS

If an analog voice terminal requires either the Voice
Announcement to Busy Voice Terminal feature or the
Simultaneous Voice and Data feature, you need to assign
two adjacent odd/even station jacks (01 and 02, 13 and 14,
etc.) on an analog station module to that voice terminal.
For Release 3, Form 1d, System Form-Station Planning
shows which stations receive either option. For Feature
Modules 1 and 2, the Master Planning Form gives this
information. The numbers of the station jacks to which
each of these stations should be connected are boxed on
the form.

The wiring requirement for either of these features is that
two voice-pairs (one pair from each jack) must be
connected from the control unit to the voice terminal.
Refer to Figure 2-6 for an example of wiring a voice
terminal for adjacent odd/even jacks. In this example, a
bridging adapter (BR-241-B1) is used to connect both
voice pairs to the voice terminal.

Note that in Figure 2-6, the wire from station jack 39 on
the line module connects to the jack labeled “Even” on the
bridging adapter. This is because the label on the bridging
adapter refers to the default intercom number, which does
not necessarily match the station jack number in terms of
odd and even. Odd/even wiring refers to jack numbers,

not

intercom numbers.

Wiring the System 2-27

Power

Supply

408 408 408 408 408

CO lines

MERLIN II System

Note:
For bridging adapter, ‘even” and "odd" refer to default intercom numbers. These numbers

do not necessarily match jack numbers in terms of odd and even.

PFT

04
03
02
01

08
07
06
05
04
03
02
01

control unit

PFT
08
07
06
05

16
15
14
13
12
11
10
09

PFT
12
11
10
09

24
23
22
21
20
19
18
17

PFT
16
15
14
13

32
31
30
29
28
27
26
25

PFT
20
19
18
17

40
39

38
37
36
35
34
33

Adjacent

odd/even

jacks

D8W cords

Line

Voice

terminal

Bridging
Adapter

(BR-241-B1)

(See Note)

Even

Station
(Voice terminal)

Odd

FIGURE 2-6 Wiring a voice terminal for adjacent odd/even jacks using a bridging

adapter.

The bridging adapter is one method of wiring two voice
pairs to a voice terminal (adjacent odd/even jacks). The
electrical connections made by this adapter are shown in
Figure 2-7.

2-28 Wiring the System

MERLIN II System

control unit

Odd numbered jack

(Even numbered

station)

Even numbered jack

(Odd numbered

station)

Bridging adapter

Even

Station (Voice

Terminal)

Odd

Voice

terminal

Line

OOOOOOOO
RTRTRTRT

44311322

OOOOOOOO
RTRTRTRT RTRTRTRT

44311322

OOOOOOOO

44311322

87654321 54

Odd station jack from

control unit

Front

682

To voice terminal

87654321

Even station jack from

control unit

Top

BR241-B1

STATION

pins pins pins

Typical 8-position jack

FIGURE 2-7 A wiring diagram of the bridging adapter for adjacent odd/even jacks.

Wiring the System 2-29

STANDARD 4-PAIR WIRING

If you are wiring for 4-pair using a 66-type block, review
the diagram in Figure 2-8. Notice that the wiring for the
additional voice pair (the even-numbered jack) terminates
in the same place on the building wiring block as the
wiring for the odd-numbered jack. The brand Rex adapter
(BR 866-JC) attaches to the block over all four pairs and
provides a modular jack for a connection to the control
unit.

2-30 Wiring the System

Brand Rex part #

BR866-JC

Standard 8-pin

jack wiring

1—T

8—R

2

R

––––

2

T

––––

3

R

––––

1

T

––––

1

R

––––

3

T

––––

4

4

––––

––––

Odd number CM jacks

to be affixed to

building wiring block

T

—1

2

R

2

T

3

R

1

T

1

R

3

T

4
4R—8

66-Block free of building

wiring; needed for jumpers

To

previous

even

number

port used

per

T

1

66-Block wired for Even number CM jacks

four-pair station runs

FIGURE 2-8 A 66-type block wired for 4-pair station runs.

R

1

from which to run jumpers

Wiring the System 2-31

—1

—8

Follow the diagram in Figure 2-9 if you are performing a
postwire surface-mounted application or if you are using

apparatus boxes in a jack field.

The postwire surface-mounting requires a 104A
connecting Block. Two 4-pair modular cords coming
from the control unit (adjacent odd/even jacks) plug into it
and the voice pairs from each connect to the wires of a
single 4-pair modular cord. The voice terminal plugs
directly into the modular cord and then has the use of the
two voice pairs.

If you are using the Z122C apparatus boxes, you need to
provide two Z601A adapters for each terminal that
requires two voice-pairs. A single 4-pair cord can then be
run from the jack field to the voice terminal that requires
two voice-pairs.

2-32 Wiring the System