AT&T DEFINITY 7500 series User manual

AT&T
555-021-717
Issue 1, November 1989
Integrated Services Digital
Network (ISDN)
7500B Data Module
Feature Package 2
User’s Manual

TO ORDER COPIES OF THIS MANUAL
Call: AT&T Customer Information Center on 800-432-6600
In Canada Call 800-255-1242
Write: AT&T Customer Information Center
2855 North Franklin Road
P.O. Box 19901
Indianapolis, Indiana 46219
Order: Document No. 555-021-717 Issue 1, November 1989
While reasonable efforts were made to ensure that the information
in this document was complete and accurate at the time of printing,
AT&T can assume no responsibility for any errors.
Changes or corrections to the information contained in this
document may be incorporated into future reissues.
Published by
The AT&T Documentation
Management Organization
Copyright© 1989 AT&T
All Rights Reserved
Printed in U.S.A.

IMPORTANT SAFETY INSTRUCTIONS
When using your telephone equipment, basic safety precautions should always be followed to
reduce the risk of fire, electric shock and injury to persons, including the following:
●Read and understand all instructions.
●Follow all warnings and instructions marked on the product.
●This product can be hazardous if immersed in water. To avoid the possibility of electric
shock, do not use it when you are wet. If you accidentally drop it into water, do not
retrieve it until you have first unplugged the line cord from the modular wall jack. Do
not plug the telephone back in until it has dried thoroughly.
●Avoid using the telephone (other than a cordless type) during electrical storms in your
immediate area. There is a remote risk of electric shock from lightning. Urgent calls
should be brief. Even though your telephone company may be using protective measures
to limit electrical surges from entering your building, absolute protection from lightning
is impossible.
●If you suspect a gas leak, report it immediately, but use a telephone away from the area
in question. The telephone’s electrical contacts could generate a tiny spark. While
unlikely, it is possible that this spark could ignite heavy concentrations of gas.
●Never push objects of any kind into this telephone through housing slots as they may
touch hazardous voltage points or short out parts that could result in a risk of electric
shock. Never spill liquid of any kind on the telephone.
●To reduce the risk of electric shock, do not disassemble this product. There are no user
serviceable parts inside. Opening or removing covers may expose you to hazardous
voltages. Incorrect reassembly can cause electric shock when the telephone is
subsequently used.
●Disconnect the cords on this product before cleaning. Do not use liquid cleaners or
aerosol cleaners. Use a damp cloth for cleaning.
●Slots and openings in the housing and the back or bottom are provided for ventilation to
protect it from overheating, these openings must not be blocked or covered. The opening
should never be blocked by placing the product on a sofa, rug, or other similar surface.
This product should never be placed near or over a radiator or heat register. This product
should not be placed in a built-in installation unless proper ventilation is provided.
●This product should be operated only from the type of power source indicated on the
marking label. If you are not sure of the type of power supply being used, contact a
qualified service person.
●Do not allow anything to rest on the power cord. Do not locate this product where the
cord will be abused by person walking on it.
●Do not overload wall outlets and extension cords as this can result in the risk of fire or
electric shock.

●Disconnect the cords on this product and refer servicing to qualified service personnel
under the following conditions:
A. When the power supply cord or plug is damaged or frayed.
B. If liquid has been spilled into the product.
C. If the product has been exposed to rain or water.
D. If the product does not operate normally by following the operating instructions.
Adjust only those controls that are covered by the operating instructions because
improper adjustment of other controls may result in damage and will often
require extensive work by a qualified technician to restore the product to normal
operation.
E. If the product has been dropped or the housing has been damaged.
F. If the product exhibits a distinct change in performance.
SAVE THESE INSTRUCTIONS
When you see this symbol on the product, refer to the instruction booklet
packed with the product for more information before proceeding.

Table of Contents
1:
INTRODUCTION
Organization of the User’s Manual
User Manual Conventions and Product Standards
Legend for Flowchart Figures
On “System Administrator”: An Important Note to All Users
2: PRODUCT OVERVIEW
Front Panel of the 7500
Rear Panel of the 7500
7500 Configurations and Features
Features Common to All Configurations
Asynchronous DCE Features
Asynchronous DTE (Modem Pooling) Features
Synchronous DCE Features
3: FRONT PANEL FEATURE ACCESS
Introduction
Main Menu
How the Buttons Work
Adjusting Display Legibility
Main Menu Items
The Home Display
EIA Data Communication Port Status Display
Synchronous Call Control Menu
Introduction
Placing and Ending Synchronous Data Calls
To Dial an Unstored Number
To Correct an Error
To Store Numbers in Memory
To Dial a Stored Number
To End a Data Call
Synchronous/Asynchronous Menu
Introduction
Test-Reset Menu
1
2
2
3
4
5
5
6
7
7
7
8
8
9
9
10
10
10
11
12
14
15
15
15
17
18
18
18
19
20
20
Introduction
Self-Test
Local Loopback Test
Remote Loopback Test
Remote Loopback Self-Test (Asynchronous Only)
Resetting Options
Single Port Configuration
Dual Port Configuration
Setting Options
Introduction
Setting Options With Help Menu
Setting Options With Help Menu — Using Attention as Example
Saving and Canceling Options, With Help
Asynchronous and Synchronous Option Tables
22
22
23
24
24
26
26
26
28
29
29
30
32
34
35
37
37
40
42
Setting Options, Without Help Menu
Setting Options Without Help Menu — Using Speed as Example
Asynchronous and Synchronous Option Tables
Saving and Cancelling Options, Without Help
i

Table of Contents
Viewing Options
Introduction
Viewing Options, With Help Menu
View Options With Help — Single Port Configuration
View Options With Help — Dual Port Configuration
Viewing Options, Without Help Menu
Service Profile Identifier (SPID)
4: DEFINITIONS OF 7500 OPTIONS
Answer
Attention
Autoadjust
Autodial
Break
Busyout
Char.erase (Character Erase)
Data.rest (Data Restriction)
DCD (Data Carrier Detect)
DTR (Data Terminal Ready)
Duplex
Echo
Edit
FCPN (Flow Control Parameter Negotiation)
Forwarding
Idle.timer
Line.erase
Local Mode
Match.speed
Min.timer (Minimum Delay Timer)
Mode
Asynchronous DCE
Synchronous DCE
Parity
Rec.flow (Receive Flow Control)
Setup
Speed
Text
Trans.flow (Transmit Flow Control)
ZCA (Zero Called Address)
5: ASYNCHRONOUS DCE CONFIGURATION
Feature Access From an Attached Data Terminal
General Information About Data Calls
Automatic Speed and Parity Adjustment
Making a Data Call
Other Ways of Dialing From Your Attached Data Terminal
Redialing the Last Data Call Made
Alphanumeric Dialing.
X.25 Call Options
Memory Dialing
Programming Telephone Numbers
Default or Hot Line Dialing
Suspending and Continuing Data Transmission During a Data Call
Commands
44
44
45
45
46
47
49
51
51
51
52
53
53
54
55
55
56
57
58
58
59
59
60
61
61
62
62
63
64
64
65
66
66
67
68
69
69
70
71
71
71
72
73
75
75
75
75
76
76
77
78
79
ii

Table of Contents
When to Type Commands
How to Type Commands
Abbreviating Commands
Data Option Profiles
List of Data Options
Types of Data Option Profiles
Active Profile, pA
Factory Profile, p0
Stored Profiles, p1 and p2
Creating (Programming) a Data Option Profile
Setting Options: Changing Your Active Profile, pA
Storing an Active Profile, pA
Activating a Stored Profile
Replacing One Stored Profile With Another
Viewing an Option Profile
Viewing Individual Option Values Within the Active Profile, pA
Typical Data Option Settings for Data Transfer
Character by Character Transmission
Line/Block at a Time Transmission
Binary (8-bit) File Transfer
Worksheet — Option Profile Settings
Getting Help
Testing Your 7500 Data Module
Local Loopback Test
Remote Loopback Test
At Mode Operation
Switching From CMD Local Mode to AT Mode
Suspending and Continuing Data Transmission During a Data Call
Exiting AT Mode and Returning to CMD Local Mode
AT Commands
Dual Port DCE Operation
Asynchronous DCE With the Multipurpose Enhancement Board
79
79
80
80
80
81
81
81
81
82
84
84
85
85
86
86
86
86
86
86
87
88
89
89
90
91
91
91
91
92
94
94
6: ASYNCHRONOUS DTE CONFIGURATION
Modem Pooling Applications
Characteristics of Modems that can be Attached to the 7500
Overview of 7500 Operation
7500 Modem Pool: Digital to Analog Network
7500 Modem Pool: Analog to Digital Network
Disconnecting a Data Call from Either Endpoint
Asynchronous DTE Data Options
Using Commands
95
95
96
96
96
97
97
98
99
7: SYNCHRONOUS DCE CONFIGURATION
Connection Types
Nailed-Up Connections
Circuit Switched Connections (CS)
On-Demand B-Channel X-25 Connections (BX Local and BX Remote)
Making a Data Call
101
101
101
101
101
101
8: INSTALLING THE 7500
Stand-Alone Installations
Stand-Alone Single Port Asynchronous DCE Configuration
Stand-Alone Dual Port Asynchronous DCE Configuration
103
103
104
105
iii

Table of Contents
Stand-Alone Asynchronous DTE Configuration
Stand-Alone Multipurpose Enhancement DCE Configuration
Stand-Alone High Speed Synchronous DCE Configuration
Installing NT1 or Terminating Resistor Adaptor
Installing the 7500 Data Module in a 77A Data Mounting
111
116
116
117
119
9: TECHNICAL INFORMATION 129
129
129
129
129
Pin 2 - Transmitted Data (BA)
Pin 3 - Received Data (BB)
Pin 4 - Request-to-Send (CA)
Pin 5 - Clear-to-Send (CB)
Pin 6 - Data Set Ready (CC)
Pin 7 - Signal Ground (AB)
Pin 8 - Received Line Signal Detect (CF) or Data Carrier Detect
Pin 9 - Positive Polarity Test Voltage
Pin 10 - Negative Polarity Test Voltage
Pin 18 - Local Loopback (LL)
Pin 20 - Data Terminal Ready (CD)
Pin 21 - Remote Loopback (RL)
Pin 22 - Ring Indicator (CE)
Pin 25 - Test Mode (TM)
7500 — Asynchronous DTE
Attached Data Communications Equipment
Data Rates
DTE EIA Interface Information
Pin 2 - Transmitted Data (BA)
Pin 3 - Received Data (BB)
Pin 4 - Request-to-Send (CA)
Pin 5 - Clear-to-Send (CB)
Pin 6 - Data Set Ready (CC)
Pin 7 - Signal Ground (AB)
Pin 8 - Received Line Signal Detect (CF)
Pins 12 and 13 - Speed Mode Indicators (CI and CI2)
Pin 18 - Analog Loopback (CN)
Pin 20 - Data Terminal Ready (CD)
Pin 21 - Remote Loopback (RL)
Pin 22 - Ring Indicator (CE)
Pin 25 - Test Mode
7500 — Asynchronous DCE
Attached Data Terminal Equipment Requirements
Data Rates
DCE EIA Interface Information 129
130
130
130
130
130
130
130
130
130
131
131
131
131
132
132
132
132
132
133
133
133
133
133
133
133
134
134
134
134
134
7500 — Synchronous DCE
Data Terminal Equipment Requirements
Data Rates
Synchronous Interface Information
Pin 7/B - Signal Ground
Pin 4/C - Request-to-Send
Pin 5/D - Ready for Sending
Pin 6/E - Data Set Ready
Pin 8/F - Received Line Signal Detect
Pins 3/R and 3/T - Received Data
Pins 17/V and 17/X - Receiver Signal Element Timing
135
135
135
135
136
136
136
137
137
137
137
iv

Table of Contents
Pins 15/Y and 15/AA - Transmitter Signal Element Timing
Pins 2/P and 2/S - Transmitted Data
137
137
Pin 20/H - Data Terminal Ready
137
Pin 22/J - Ring Indicator
138
Pin 18/L - Local Loopback
138
Pin 21/N - Remote Loopback
Pin 25/NN - Test Mode
7500 — Automatic Calling Unit Interface
Functional Description of Interchange Circuits
Circuit SG - Signal Ground (CCITT 201)
Circuit CRQ - Call Request (CCITT 202)
Circuit PWI - Power Indication (CCITT 213)
Circuit DLO - Data Line Occupied (CCITT 203)
Circuit DSC - Distant Station Connected (CCITT 204)
Circuit ACR - Abandon Call and Retry (CCITT 205)
138
138
139
140
140
140
141
141
141
141
Digit Signal Circuits
141
Circuit PND - Present Next Digit (CCITT 210)
142
Circuit DPR - Digit Present (CCITT 211)
143
Packet Assembler Disassembler (PAD) Capabilities
144
147
REFERENCE
General Features
147
Asynchronous DCE 7500
147
Asynchronous DTE 7500 148
Synchronous DCE 7500 148
Optional Enhancement Boards
Multipurpose Enhancement Board 150
150
Second Asynchronous Interface Enhancement Board 150
High Speed Synchronous Enhancement Board 150
APPENDIX 151
INDEX 155
v

List of Figures
Figure 1:
Figure 2:
Figure 3:
Figure 4:
Figure 5:
Figure 6:
Figure 7:
Figure 8:
Figure 9:
Figure 10:
Figure 11:
Figure 12:
Figure 13:
Figure 14:
Figure 15:
Figure 16:
Figure 17:
Figure 18:
Figure 19:
Figure 20:
Figure 21:
Figure 22:
Figure 23:
Figure 24:
Figure 25:
Figure 26:
Figure 27:
Figure 28:
Figure 29:
Figure 30:
Figure 31:
Figure 32:
Figure 33:
Figure 34:
Figure 35:
Figure 36:
Figure 37:
Figure 38:
Figure 39:
Figure 40:
Figure 41:
Figure 42:
Figure 43:
Figure 44:
Figure 45:
Figure 46:
Figure 47:
Figure 48:
The 7500 Data Module
An Example of a Flowchart
Front Panel of the 7500
Rear Panel of the 7500
7500 Menu Map
Main Menu Items
Typical EIA Status Display (Dual Port Async DCE Configuration)
Synchronous Call Control Menu
Synchronous/Asynchronous Menu
Test-Reset Menu
Reset Options Menu, Single Port Configuration
Reset Options Menu, Dual Port Configuration
With and Without Help Menus
Set Options, With Help Menu, Dual Port Configuration
Setting an Option Via the With Help Menu, Using the Attention Option as an
Example
Set Options, Without Help Menu
Factory Option Settings, Without Help Menu
Viewing Options, With Help Menu
Viewing Options, With Help, 2 Ports
View Options, Without Help Menu
Going Between Local Mode and Data Mode During a Data Call
The 7500 Used in a Modem Pooling Application
Rear Panel of the 7500
Removing the Door
Removing the Knock-Out
Installing the Second Asynchronous Interface Enhancement Board
Top View
Top View with Second Asynchronous Interface Enhancement Board Installed
Rear Panel of the 7500
Removing the Door
Top View Showing Silver Arrow
7500 Showing Location of the DCE/DTE Flipboard
Removing the DCE/DTE Flipboard
Reversing the DCE/DTE Flipboard
Installation Using a Power Supply and Terminating Resistor
Installation Using a Power Supply and an NT1
Installation Using a Power Supply
Installation of the 77A Data Mounting
Data Module With Display End Up
Plugging in the Power Connector to a Data Module
Plugging in the Power Cord to a Mounted Power Supply
Plugging in the Power Cord to an Outlet
L3 or L4 Adaptor
Terminating Resistor and The L3 or L4 Adaptor
Terminating Resistor’s Power Connections (Without an L3 or L4 Adaptor)
Data Module and Line Jack Connections
Data Interface Cables Connected to the Back of a Data Module
Securing Cable Through Plastic Twist Locks
1
3
5
6
9
11
14
16
21
22
27
28
29
31
33
39
43
44
46
48
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95
104
105
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110
111
112
113
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115
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120
120
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vi

List of Tables
Table A:
Table B:
Table C:
Table D:
Table E:
Table F:
Table G:
Table H:
Table I:
Table J:
Table K:
Table L:
Table M:
Table N:
Table O:
Table P:
Table Q:
Table R:
Table S:
Table T:
Table U:
Table V:
Table W:
Table X:
Table Y:
Table Z:
Table AA:
Home Display Terms
Asynchronous DCE and DTE Options With Help
Synchronous DCE Options, With Help
Asynchronous DCE and DTE Options, Without Help
Synchronous DCE Options, Without Help
Commands, Their Abbreviations and Descriptions
Data Option Values (Highlighting Factory Settings)
Data Option Profiles
AT Commands and Applications
S-Registers
DTE Options
WP90780 L3 25-Pair Cable Adapter for use with Direct Cabling to Multiple
Mount NT1
WP90780 L4 25-Pair Cable Adapter for use with AT&T Uniform Wiring Plan
Asynchronous DCE Pin Assignments
Asynchronous DTE Pin Assignments
Speed Mode Indicator
Synchronous DCE Pin Assignments
V.35 Adapter Cable
Interface Connector Pin Identification
Interchange Circuits By Category
Digit Signal Character Set
X.3 Parameters
Asynchronous Configuration
Synchronous Configuration
Hexadecimal Values for ASCII Characters
X.25 Cause Messages
Q.931 Cause Messages
13
35
37
40
41
79
80
82
92
93
98
126
127
129
132
134
135
136
139
140
142
144
149
149
151
152
153
vii

CHAPTER 1: INTRODUCTION
Congratulations on the addition of the AT&T 7500 Data Module to your Integrated Services Digital
Network (ISDN) communications system. Following our tradition of excellent quality and high
reliability, the new 7500 is designed to provide you with the latest in telecommunications technology
(Figure 1).
Figure 1: The 7500 Data Module
The AT&T ISDN 7500 Data Module is a terminal adaptor intended primarily for connecting
unattended data terminal equipment (DTE) or data communications equipment (DCE) to the ISDN
network. The 7500 is a stand alone unit which can be inserted into a multiple mounting (that is rack
mounting). The 7500 has no voice functions.
The 7500 provides you with flexible data communications capabilities in one unit. The 7500 can be
configured in a number of ways to allow attached DTE and DCE tO send and receive data through the
digital network.
1

CHAPTER 1: INTRODUCTION
Organization of the User’s Manual
This manual is arranged into the following chapters:
●
●
●
●
●
●
✙
●
●
●
●
CHAPTER 1: INTRODUCTION
CHAPTER 2: PRODUCT OVERVIEW — Gives an overview of the 7500 features and
configurations.
CHAPTER 3: FRONT PANEL FEATURE ACCESS — Explains how to use menus accessible from
the front panel of the 7500.
CHAPTER 4: DEFINITIONS OF THE 7500 OPTIONS — Gives definitions of options available
with the 7500.
CHAPTER 5: ASYNCHRONOUS DCE CONFIGURATION — Describes use of the 7500 in an
asynchronous DCE configuration.
CHAPTER 6: ASYNCHRONOUS DTE CONFIGURATION — Describes use of the 7500 in an
asynchronous DTE configuration.
CHAPTER 7: SYNCHRONOUS DCE CONFIGURATION — Describes use of the 7500 in a
synchronous DCE configuration.
CHAPTER 8: INSTALLATION — Gives procedure to install your 7500.
CHAPTER 9: TECHNICAL DESCRIPTION — Provides information for technical personnel.
REFERENCE — Provides information for technical personnel.
APPENDIX — Provides hexadecimal conversion table for the ASCII characters, and X.25 and
Q.931 cause messages.
User Manual Conventions and Product Standards
The following conventions are used in this manual:
●
●
●
●
●
●
Items in boxes, for example, [ NEXT/NO ], represent buttons and keys to be pressed.
Items in bold characters, for example, 3784, represent information entered with the data terminal
keyboard.
Items in reverse video, for example, [DONE? ] represent messages on the 7500 display or the
terminal screen.
Items in italics, for example HOME, represent variables.
is an icon that appears throughout this manual. It means you should pay special
attention to that information. It often significantly qualifies previously presented
procedures or descriptions.
is an icon which appears occasionally in this manual. It means there is a
possibility of equipment damage.
2

CHAPTER 1: INTRODUCTION
●is an icon which appears occasionally in this manual. It means there is a
possibility of service interruption.
●Where this product employs the EIA-232D standard interface, older equipment which adheres to
the RS-232C standard can also be connected.
Legend for Flowchart Figures
Figure 2: An Example of a Flowchart
Figure 2 shows a portion of a typical 7500 manual flowchart figure.
Callouts (1), (3), and (5) represent messages displayed on the 7500's front panel. Messages are
always pictured in boxes.
Callouts (2), (4), and (6) represent the three button on the 7500's front panel: [ NEXT/NO ].
[ ENTER/YES ], and [ BACK ].
Beginning from the top of the flowchart [TEST-RESET? ] is displayed on the front panel. Pressing
[ NEXT/NO ] will display the message [SET OPTIONS? ]. Pressing [ BACK ] while [SET OPTIONS? ] is
displayed will return the display to [TEST-RESET? ]. Pressing [ ENTER/YES ] while [SET OPTIONS? ] is
displayed will display
[WITH HELP? ].
3

CHAPTER 1: INTRODUCTION
On “System Administrator”: An Important Note to All Users
Throughout this manual, we ask you to speak to your “system administrator.” To whom do we
refer? In your company, it is the person who has been given the overall responsibility for ISDN —
including all terminals as well as the switch. His or her own title will vary from business to business.
It may be "system manager," "telecommunications manager," "data communications manager," or
something less generic and more unique to your company.
You may wonder why this reference to a system administrator occurs so often. The answer lies in
the sophisticated nature of ISDN. In addition, every ISDN is configured to meet the specific needs of
each customer. Your system administrator knows the unique configuration of your particular ISDN
system and can answer your questions based on this knowledge. Your installation can and
should reflect the individual uniqueness of your company.
4

CHAPTER 2: PRODUCT OVERVIEW
Front Panel of the 7500
The front panel of the 7500 is shown in Figure 3.
Figure 3: Front Panel of the 7500
The front panel has the following features:
●
●
●
●
Power/Test lamp — The red Power/Test lamp lights when power is supplied to the 7500. The
lamp flashes during all tests.
Data lamp — The green Data lamp lights when a data call is in progress. The lamp flashes
during self-test and when you are receiving an incoming data call that has not yet been answered.
Display — The display has one 16-character line on which status information and option settings
are displayed. The legend above the display identifies the character positions for display of the
EIA Interface lead status. The legend below the display identifies the character positions for
option settings. These settings are explained later in this manual.
[ NEXT/NO ], [ BACK ], and [ ENTER/YES ] buttons — These buttons are used to step through each
menu, set data communication options and functions, and adjust the contrast of the display.
5

CHAPTER 2: PRODUCT OVERVIEW
Rear Panel of the 7500
The rear panel of the 7500 is shown in Figure 4.
Figure 4: Rear Panel of the 7500
The rear panel has the following features:
●Line Jack — Used to connect the 7500 to the ISDN telephone network.
Phone Jack — If your system supports multiple ISDN terminals on the same telephone line (see
●
your systems administrator), you can use this phone jack to connect a second ISDN terminal.
●Power Connector — Used to connect the 7500 to its DC power supply. The power supply is
connected in turn to the standard AC power.
●Communications Ports 1 and 2 — Port 1 is used to connect the 7500 to a data terminal,
computer, or modem. Depending upon which enhancement board is installed, Port 2 can be used
to connect a second data terminal, an automatic calling equipment (RS-366 interface), or a data
terminal equipment with a V.35 interface.
6

CHAPTER 2: PRODUCT OVERVIEW
7500 Configurations and Features
Using the available hardware and software options, you can configure your 7500 as:
●
Asynchronous DCE,
●Asynchronous DTE, or
●Synchronous DCE.
The procedures for changing the configuration are described in CHAPTER 8: INSTALLING THE
7500.
This manual is arranged in sections that reflect the operational differences in the configurations of
the 7500. In all configurations, you may operate the 7500 using the buttons and display on its front
panel. The front panel menu system is the first method of operation described.
If your 7500 is configured as an asynchronous DCE, and it is attached to a data terminal or personal
computer, you will probably want to operate it from the keyboard of your attached terminal. This
method of operation is described in CHAPTER 5: ASYNCHRONOUS DCE CONFIGURATION.
If your 7500 is configured as an asynchronous DTE used in a modem pool, refer to CHAPTER 6:
ASYNCHRONOUS DTE CONFIGURATION to learn more about modem pooling operation. The
primary mode of accessing asynchronous DTE features is through the front panel of the 7500.
The capabilities of the synchronous DCE configuration are accessed exclusively through the front
panel of the 7500 (See CHAPTER 7: SYNCHRONOUS DCE CONFIGURATION).
A brief outline of the capabilities of the different configurations follows.
Features Common to All Configurations
The following operations can be controlled with buttons and display on the 7500:
●Data option settings
●Self-test, local, and remote loopback tests, EIA lead status
●
Program ID
●Contrast adjustment.
Asynchronous DCE Features
●EIA-232D interface.
●Packet and circuit switched data communications.
●
Data options can be changed and data calls can be setup via commands from the EIA-232D
interface. These commands can be typed from the keyboard of an attached terminal or generated
from a computer.
●Ability to change options without dropping a data call.
●Automatic or manual answering of incoming data calls.
●Data rates of 0.3, 1.2, 2.4, 4.8, 9.6, and 19.2 kilobits per second (kbps).
●Asynchronous full-duplex operation.
7

CHAPTER 2: PRODUCT OVERVIEW
●One of the following two optional enhancements:
— RS-366 Automatic Calling Unit (ACU) interface.
— Second asynchronous EIA-232D interface. (Two D-channel packet data calls — or one D-
channel packet call and one B-channel circuit call — can operate simultaneously. Two B-
channel circuit switched calls, however, cannot operate simultaneously.)
Asynchronous DTE (Modem Pooling) Features
●EIA-232D interface.
●Packet or circuit switched data communications.
●Data rates of up to 19.2 kilobits per second (kbps).
●Asynchronous full-duplex operation.
●Automatic answering of incoming data calls.
●Data options set via the analog-side data terminal keyboard on a call by call basis.
●5ESS® switch modem pooling feature support.
Synchronous DCE Features
The synchronous DCE features with the Multipurpose Enhancement Board are as follows:
●EIA-232D interface.
●Circuit switched or nailed-up data communication.
●Data rates of 1.2, 2.4, 4.8, 9.6, 19.2, 56 or 64 kilobits per second (kbps).
●Full-duplex operation at all the above speeds.
●Synchronous half-duplex emulation at 1.2 to 56 kbps.
●Automatic answering of incoming data calls.
●RS-366 Automatic Calling Unit (ACU) interface.
●
Autodial.
The synchronous DCE features with the High Speed Synchronous Enhancement Board are as
follows:
●V.35 interface.
●Circuit switched or nailed-up data communication.
●Data rates of 48, 56 or 64 kilobits per second (kbps).
●Full-duplex operation at all the above speeds.
●Synchronous half-duplex emulation at 56 kbps only.
●Automatic answering of incoming data calls.
●
Autodial.
8

CHAPTER 3: FRONT PANEL FEATURE ACCESS
Introduction
The 7500 has a structured menu that you can use to exercise its features as shown in Figure 5.
Note: The Call Control items appear only in synchronous circuit switched configurations.
The Sync/Async items appear only in configurations supporting both modes.
* (Home) in this figure refers to one of the messages described in Table A.
Figure 5: 7500 Menu Map
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