Lucent Technologies AT-T 7400B User Manual
AT&T 7400B Data Module
User’s Guide
555-020-707
Issue 1
November 1989
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Document No. 555-020-707 Issue 1, November 1989
This equipment has been tested and found to comply with the limits for a Class A digital
device, pursuant to Part 15 of the FCC Rules. These limits are designed to provide
reasonable protection against harmful interference when the equipment is operated in a
commercial environment. This equipment generates, uses, and can radiate radio
frequency energy and, if not installed and used in accordance with the instruction
manual, may cause harmful interference to radio communications. Operation of this
equipment in a residential area is likely to cause harmful interference in which case the
user will be required to correct the interference at his own expense.
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.
DEFINITY is a trademark of AT&T. Hayes is a registered trademark and Smartmodem is a trademark of
Hayes Microcomputer Products, Inc. Microsoft and MS-DOS are registered trademarks of Microsoft
Corporation. PROCOMM is a registered trademark of Datastorm Technologies, Inc. RELAY GOLD is a
registered trademark of Relay Communications, Inc. CROSSTALK is a registered trademark of Digital
Communications Associates. CompuServe is a registered trademark of H&R Block. Delphi is a registered
trademark of Delphi Systems, Inc. Dow Jones News is a registered trademark of Dow Jones & Company,
Inc. LEXIS/NEXIS are registered trademarks of Mead Data Central, Inc. Newsnet is a registered
trademark of Newsnet, Inc. Official Airline Guide is a registered trademark of the Reuben H. Donnelley
Corporation.
Copyright© 1989 AT&T
All Rights Reserved
Printed in U.S.A.
CONTENTS
PREFACE: ABOUT THIS GUIDE
Typographical Conventions
Organization of This Guide
Related Documentation
1
CHAPTER 1: INTRODUCTION
External Features
2
CHAPTER 2: INSTALLATION
Hardware and Software Requirements
Hardware Installation
Initial System Checks
If You Are Using a PC
If You Are Using a Dedicated Terminal
3
CHAPTER 3: FIRST TIME USERS
Operating Modes
Essential AT Commands
Sample Command Lines
A Sample On-Line Session
i
i
ii
1-2
2-1
2-7
2-12
2-12
2-12
3-1
3-2
3-4
3-6
4
CHAPTER 4: OPERATION AND CONFIGURATION
CONFIGURATION PARAMETERS
Operating Modes
Issuing Commands
From Data Mode to Command Mode and Back
Dialing a Number
Repeating a Command
Storing a Telephone Number
Automatic Answering
Remote Site Use
RESET AND CONFIGURATION RECALL
4-1
4-2
4-3
4-6
4-6
4-7
4-7
4-8
4-9
4-9
5
CHAPTER 5: TROUBLESHOOTING
How to Use This Chapter
A
APPENDIX A: AT COMMAND SET
B
APPENDIX B: S-REGISTERS
C
APPENDIX C: APPLICATION NOTES
PBX Application Notes
PC Applications Guide
Procomm Plus
Relay Gold
Crosstalk XVI
D
APPENDIX D: QUICK-REFERENCE SUMMARIES
GL
GLOSSARY
5-1
C-1
C-1
C-2
C-5
C-8
DEFINITY Communications System
7400B Data Module
User’s Guide
PREFACE: ABOUT THIS GUIDE
PREFACE: ABOUT THIS GUIDE
Page i
The purpose of this guide is to provide information for installing,
operating, and maintaining the 7400B Data Module.
TYPOGRAPHICAL CONVENTIONS
Throughout this guide, command lines that you type are shown in
typewriter-style characters, and responses that the 7400B Data Module
returns are shown in italics. The following is an example.
at h
[ Enter ]
OK
Note the following characteristics of the display representation:
The first line is a command line as it should be typed. The [ Enter ]
●
symbol, when shown, indicates that you must press the Enter or
Return key to complete the command line.
●
Spaces are used to separate commands in some examples shown in
this guide. In actual use, the spaces may be typed, but they are not
required.
●
The second line in the example shows a typical response returned by
the data module.
ORGANIZATION OF THIS
The following paragraphs summarize the chapters and appendices
GUIDE contained in this guide.
Chapter 1: Introduction. Discusses the basic operating features
of the AT&T 7400B Data Module and describes the external
indicators and connectors.
Chapter 2: Installation. Describes the hardware and software
required for installing the data module, and outlines procedures for
preparing the data module for operation.
Chapter 3: First Time Users. Provides some basics on 7400B
Data Module operation, describes how to use a few AT commands
that are essential for most data communications operations, and
then outlines a typical on-line session.
Chapter 4: Operation and Configuration. Describes how to
change, store, and recall configuration parameters, outlines how to
create and save custom, configuration profiles, and discusses more
advanced command usage with example command lines.
PREFACE: ABOUT THIS GUIDE
Page ii User’s Guide
DEFINITY Communications System
7400B Data Module
Chapter 5: Troubleshooting. Describes procedures for
troubleshooting problems that may be encountered while
configuring and operating the 7400B Data Module.
Appendix A: AT Command Set. Contains an explanation of each
AT command accepted by the 7400B Data Module.
Appendix B: S-Registers. Contains an explanation of each Sregister used by the 7400B Data Module.
Appendix C: Application Notes. Contains notes on how to
configure some popular PC data communications software
packages for use with the 7400B Data Module, and provides a list
of application notes that describe how to administer specific AT&T
PBX systems for using the data module.
Appendix D: Quick-Reference Summaries. Contains quickreference summaries of AT commands, S-registers, result codes,
factory-default configuration settings, EIA-232-D connector pin-
outs, ASCII character set.
RELATED DOCUMENTATION
A glossary and an index are provided at the rear of this guide.
The following is a list of other manuals that may provide helpful
information while installing and using the 7400B Data Module. Since
each user may have different equipment and software preferences or
availability, only generic titles are given for the manuals.
If you are using a terminal device other than a PC:
User's guide for your terminal device. You may need information
about the configuration and capabilities of your terminal device
from this manual during the installation and preliminary operation
of the 7400B Data Module.
If you are using a PC as your terminal:
User’s guide for Microsoft® MS-DOS®. You may need this
reference for explanations of commands used by your PC to install,
configure, and run your data communications software.
User's guide for your data communications software. You may need
this guide for information on how to configure your terminal
emulation software to access the 7400B Data Module.
DEFINITY Communications System CHAPTER 1: INTRODUCTION
7400B Data Module
User’s Guide
Page 1-1
CHAPTER 1: INTRODUCTION
This chapter discusses the basic operating features of the 7400B Data
Module and describes the external indicators and connectors.
The data module provides an asynchronous data service link between a
Data Terminal Equipment (DTE) device and the following AT&T digital
PBX equipment:
●
DEFINITY™ Communications System Generic 1
●
DEFINITY Communications System Generic 2
●
System 75
●
System 85
Note:
Unless a specific DTE device is intended, the words terminal
device shall be used throughout this guide to represent any
applicable DTE device, including a dumb terminal, a printer,
a plotter, or a personal computer (PC) with an appropriate
data communications software package.
An EIA-232-D standard interface (formerly EIA recommended standard
RS-232-C) connects the terminal device to the 7400B Data Module, and
a standard Digital Communications Protocol (DCP) interface (using a
type D8W modular telephone cord) connects the data module to the
digital PBX.
An internal DIP-switch option allows the 7400B Data Module to be set
for use either with or without a telephone. In without-telephone mode,
the data module supports data service only, but in with-telephone mode
the data module provides simultaneous data and voice service (requires
an associated AT&T 7400-series DCP digital voice terminal).
Note:
If a 7400-series voice terminal with data features is used
with the 7400B Data Module, data service is provided by the
7400B Data Module and the data features of the voice
terminal cannot be used.
The 7400B Data Module uses a subset of the industry-standard AT
command set and supports transmission speeds of 300, 1200, 2400,
4800, 9600, and 19,200 bps.
Additional features of the 7400B Data Module, described in later
chapters of this manual, include:
●
non-volatile, read-write memory for storing two data options
profiles and up to four telephone numbers
●
automatic speed and parity adjustment
CHAPTER 1: INTRODUCTION
Page 1-2
●
data metering option
●
programmable control characters
●
self-test at start-up
●
local and remote loopback tests
●
test duration timers
●
voice terminal powered by the PBX is not affected if ac power
DEFINITY Communications System
7400B Data Module
User’s Guide
is removed from the 7400B Data Module
EXTERNAL FEATURES The external features of the front and rear panels of the 7400B Data
Module and the separate power supply unit are described in this section.
The data module has a removable access panel on top of the unit, which
is described further in the hardware installation section of Chapter 2,
“Installation.”
Front Panel
The front panel of the 7400B Data Module is shown in Figure 1-1, and
the 10 LEDs on the front panel are described in Table 1-1. In addition to
providing indications for normal operating modes, all of the LEDs are
also used as status indicators when the 7400B Data Module is first
powered on and the internal self-test is running.
Figure 1-1. Front Panel
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7400B Data Module
User’s Guide
CHAPTER 1: INTRODUCTION
Page 1-3
Connector
POWER/
TEST
DATA
METERING
AA
CD
RD
SD
TR
OH
Description
This red LED lights as long as power is applied to the data module. This LED
flashes during any test mode, except the start-up self-test. It also flashes along
with the DATA LED if the connection with the PBX is lost.
This red LED lights to indicate the state of the CTS (Clear To Send) output lead
when the Data Metering option is enabled.
Automatic Answer. This red LED flashes to indicate an incoming call and
lights continuously when the data module is operating in Automatic Answer
mode.
Carrier Detect. This red LED lights as long as communication is established
with the far end device.
Receive Data. This red LED lights when received data is being transferred
from the 7400B Data Module to the local terminal device.
Send Data. This red LED lights when transmitted data is being transferred from
the local terminal device to the 7400B Data Module.
Terminal Ready. If the &d0 option is enabled, the red LED is on continuously;
if either the &d1 or &d2 option is enabled, this LED indicates the state of the
DTR lead (see description of &d command in Appendix A).
Off Hook. This red LED lights continuously from the time a data
communications call is initiated until the call is terminated.
CHECK
SPEED
This red LED lights when a call set up fails because of an incompatibility
between the configuration of the local terminal device and the far end device.
The incompatibility will usually occur if a common operating speed cannot be
achieved between the two endpoints. Chapter 5, “Troubleshooting,” provides
information about this and other conditions that may cause this LED to light.
DATA
This green LED lights to indicate that a data call is in progress. This LED
flashes along with the POWER/TEST LED if the connection with the PBX is
lost.
TABLE 1-1 Front Panel LED Indicator Descriptions
CHAPTER 1: INTRODUCTION DEFINITY Communications System
7400B Data Module
Page 1-4 User's Guide
Rear Panel
The rear panel of the 7400B Data Module is shown in Figure 1-2, and
the connectors located on the rear panel are described in Table 1-2.
Figure 1-2. Rear Panel
Connector Description
PHONE
This connector accepts one end of the D8W telephone line cord used to connect
a telephone or voice terminal to the data module.
LINE This connector accepts one end of the D8W telephone cord that connects
between the data module and the PBX wall jack.
POWER
This connector accepts the output cable of the separate power supply unit used
with the 7400B Data Module.
PORT 1 This connector accepts a male plug from the EIA-232-D (or RS-232-C) cable
that connects between the data module and the terminal device.
PORT 2
Not used by the 7400B Data Module.
TABLE 1-2 Rear Panel Connector Descriptions
DEFINITY Communications System
7400B Data Module
User’s Guide
CHAPTER 1: INTRODUCTION
Page 1-5
Power Supply Unit
A separate power supply unit is required with the 7400B Data Module.
This unit connects between a grounded AC outlet and the “POWER”
connector at the rear of the data module. This power supply unit
provides the necessary operating voltages for the data module.
Caution:
Make certain that the AC outlet to which you connect the
power supply is unswitched (for example, not controlled
by a wall switch or light dimmer).
Instructions for installing the power supply unit with an illustration are
provided in the hardware installation section of Chapter 2,
"Installation."
DEFINITY Communications System
7400B Data Module
User’s Guide
CHAPTER 2: INSTALLATION
Page 2-1
CHAPTER 2: INSTALLATION
This chapter describes the hardware and software required for installing
the data module, and outlines procedures for preparing the data module
for operation.
HARDWARE AND SOFTWARE REQUIREMENTS
In addition to the 7400B Data Module and the required separate power
supply, you will need the following items:
●
an asynchronous data terminal device or a personal computer
(PC) with data communications software
●
an EIA-232-D interface (formerly RS-232-C) cable to connect
between the terminal device and the data module
●
a type D8W telephone cord for Data Communications Protocol
(DCP) connection between the Data Module “LINE” jack and
the PBX wall jack
●
(optional) an AT&T 7400-series DCP digital voice terminal
(and associated adjunct equipment, if applicable)
●
(optional) a second type D8W cord to connect between the data
module “PHONE” jack and optional voice terminal (you may
need an adjunct power supply, adapter, and D6AP cord, as
applicable)
Figure 2-1 illustrates the needed hardware items for an arrangement
without a telephone, Figure 2-2 shows the set up for using a telephone
without adjunct equipment, and Figure 2-3 shows a similar setup with
some typical adjunct equipment.
CHAPTER 2: INSTALLATION
Page 2-2
DEFINITY Communications System
7400B Data Module
User’s Guide
PERSONAL
COMPUTER
PBX
WALL
JACK
D8W CORD
7400B DATA
MODULE
EIA
CABLE
POWER
SUPPLY
Figure 2-1. Typical Standalone Installation
DEFINITY Communications System
7400B Data Module
User’s Guide
CHAPTER 2: INSTALLATION
Page 2-3
Figure 2-2. Typical Installation with Telephone
CHAPTER 2: INSTALLATION
Page 2-4
DEFINITY Communications System
7400B Data Module
User’s Guide
Figure 2-3. Typical Installation with Telephone
and Adjunct Equipment Requiring Auxiliary Power
DEFINITY Communications System
7400B Data Module
User’s Guide
CHAPTER 2: INSTALLATION
Page 2-5
About the Terminal Device The 7400B Data Module operates with any asynchronous data terminal
device that has an EIA-232-D (or RS-232-C) serial port connector. If
you are using a PC as your terminal, you will need a suitable data
communications software package.
Also, you must set the appropriate configuration options before
connecting the 7400B Data Module to a printer or plotter. To do this,
connect a data terminal or PC to Port 1 of the data module, change the
necessary configuration parameters, remove the data terminal or PC, and
then connect the printer of plotter. The configuration parameters used
for this type of operation are described in Chapter 4, "Operation and
Configuration," in a section titled “Remote Site Use.”
EIA-232-D cables and data communications software packages are
described in the following paragraphs.
Selecting an EIA-232-D Cable
Selecting Data Communications Software
Select an EIA-232-D with a male connector at one end to mate with the
Port 1 connector of the 7400B Data Module, and a connector of the
appropriate "gender" at the other end to mate with the communications
port of your terminal device.
Note:
Cables with the earlier RS-232-C designation will also work.
The most common EIA-232-D cables are supplied with a male
connector at both ends. If you have this type of cable and the EIA-232D port on your terminal device is a male connector, you can use a cable
adapter commonly referred to as a “gender changer”. Otherwise, obtain
an EIA-232-D cable that has the appropriate gender connector at each
end to fit your application needs.
The purpose of data communications software is to allow your PC to
operate as an asynchronous data communications terminal. Of the many
software packages available, all perform essentially the same functions,
but often in significantly different ways.
If you do not already have a communications software package, consult
with an experienced user for advice on selecting software to suit your
data communications needs. The following, though not required, are a
few helpful features that you may wish to look for in the software you
select:
●
Terminal mode. Also called local mode or chat mode, this
feature allows you to issue commands to the 7400B Data
Module. The software that you select must have some form of
terminal mode.
●
Dialing directory. This feature allows you to store several
frequently called numbers, often along with configuration of
the data options needed for completing the connection.
CHAPTER 2: INSTALLATION
Page 2-6
DEFINITY Communications System
7400B Data Module
User’s Guide
●
Predefine data options profiles. Some programs include
completely defined data option profiles (also called
configuration profiles) for popular modems. If available, select
the options profile for the Hayes® Smartmodem 2400™.
●
Command files. These files, also called script files, allow you
to define a group of commands that may be executed for
automatically logging into specific remote devices.
Appendix C, “Application Notes,” provides guidelines for using a few
of the more popular communications software packages with the 7400B
Data Module.
Selecting DCP Cords
Selecting DIP-Switch Options
The 7400B Data Module is supplied with a 5-foot D8W cord. Use this,
or obtain the appropriate length D8W telephone cord for DCP
connection between the 7400B Data Module and the PBX wall jack. If
you are using the with-telephone option, you will need a second D8W
telephone cord to connect between the data module and your telephone
or voice terminal.
Three hardware options may be selected by setting switches on an
internal 8-position DIP switch (SW1). These options are described here,
and procedures for setting the switches are provided in a later section
titled “Setting the Hardware Option DIP Switches.”
With/Without Telephone Option (SW1-1)
When this option is set for operation without an associated telephone
(SW- 1 set to " WITHOUT PHONE"), the 7400B Data Module offers
only data service between a terminal device and a remote system.
Setting this option for operation with an associated voice terminal (SW1 is set to “WITH PHONE”) enables simultaneous data and voice
service over the same line from the PBX.
When the 7400B Data Module is optioned for “WITH PHONE,” an
AT&T 7400-series DCP digital voice terminal is connected to the data
module only for its voice service features; data service is provided
directly from the 7400B Data Module, and any data features that the
voice terminal may offer cannot be used.
Note:
A change in the setting of this option becomes effective
when the data module is powered on after being powered
off. The setting of this option cannot be changed
arbitrarily—it must agree with how the line is administered
at the PBX. For information on how to administer the
7400B Data Module at the PBX for use with or without a
telephone, refer to Appendix C, “Application Notes.”
DEFINITY Communications System
7400B Data Module
User’s Guide
CHAPTER 2: INSTALLATION
Page 2-7
Data Metering Option (SW1-5)
When the data metering option is disabled (SW1-5 set to "OFF"), the
transfer speed of the 7400B Data Module will adjust to match the
transfer speed of the remote system. The C0NNECT xxxx message
displayed when a connection is completed will always indicate the far
end speed.
When this option is enabled (SW1-5 set to "ON"), it allows the user to
set-up a call to a remote end device that is running at a lower speed than
the local data module. The CONNECT xxxx message will always
indicate the speed of the local data transfer. The data module performs
the speed conversion and uses the CTS lead to flow-control the user’s
terminal if it is sending too much data too fast. During the data transfer,
the DATA METERING LED indicates the state of the CTS lead.
Note:
If you are using a PC with a data communications package,
or a dedicated terminal that does not support CTS control,
you cannot make file transfers with the data metering option
enabled.
A change in the setting of this option becomes effective immediately
when the data module is in the idle mode or as soon as it is returned to
the idle mode. The data module is in idle mode any time that it is not in
test mode or connected to an active data call.
Make Busy on Local Loop Option (SW1-8)
This option controls the make-busy feature of the 7400B Data Module.
When the option is enabled (SW1-8 set to "ON"), the data module will
busyout the DCP line when either the Local Loopback or Local
Loopback/Self-Test mode is entered. The busyout condition is released
when the test ends.
Note: A change in the setting of this option becomes effective
immediately when the data module is in the idle mode or as
soon as it is returned to the idle mode. The data module is in
idle mode any time that it is not connected to an active data
call.
HARDWARE INSTALLATION
This section outlines procedures for setting the hardware options DIP
switches on the Data Module, connecting the EIA-232-D cable,
installing the power supply, and connecting the D8W telephone cord(s).
Caution:
To avoid possible shock hazards and damage to the
equipment, you should perform the installation steps in
the order given.
CHAPTER 2: INSTALLATION
Page 2-8
DEFINITY Communications System
7400B Data Module
User’s Guide
Setting the Hardware
Three hardware options are selected by setting switches on an internal
Option DIP Switches 8-position DIP switch. Setting these switches is described in the
following paragraph; however, for more information about using these
options, refer to Chapter 4, “Operation and Configuration.”
Note:
The factory-default settings of these switches are correct for
the vast majority of applications. Check the default settings
shown in Table 2-1 to determine whether you need to make
any changes.
Telephone
SW1-1
Without Phone ON
With Phone OFF
(factory-default)
Data Metering
SW1-5
On—enabled ON
Off—disabled
OFF
(factory-default)
Busy Out on Local Loop SW1-8
On—enabled
Off—disabled
ON
OFF
(factory-default)
TABLE 2-1 Option DIP Switch Settings
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User’s Guide
CHAPTER 2: INSTALLATION
Page 2-9
To access and set the hardware option switches, refer to Figure 2-4 and
perform the following:
Figure 2-4. Accessing the Hardware Option Switches
CHAPTER 2: INSTALLATION
Page 2-10
DEFINITY Communications System
7400B Data Module
User’s Guide
Caution:
Disconnect all cables and telephone cords attached at the
rear of the unit. Failure to disconnect all cables and
cords at this point could result in permanent damage to
the 7400B Data Module.
Remove the top access panel of the data module as follows:
1.
While applying a gentle lifting pressure at the rear edge of
a.
the access panel, insert the tip of a ball-point pen or other
suitable device into each of the two tab-lock holes in the
rear panel to release the locking tabs.
b.
Lift and remove the access panel.
If a ROM board is installed just inside the access opening of the
2.
Data Module, grasp the edges of the ROM board inside the access
opening and lift the board out of its socket.
Locate the 8-position DIP switch on the main circuit board,
3.
approximately in the center of the area exposed by the access
opening.
4.
Set the appropriate positions of this DIP switch as shown in the
Table 2-1.
If a ROM board was removed in step 2, reinsert the board into its
5.
connector.
Connecting the EIA-232-D Cable
Replace the access panel by placing it into position and pressing
6.
down at the rear edge to engage the locking tabs.
Connect the EIA-232-D cable between the Data Module and the
terminal device as follows:
Insert a male connector of the EIA-232-D cable into the connector
1.
labeled PORT 1 on the rear panel of the Data Module. Tighten
both connector retaining screws.
2.
Insert the other end of the EIA-232-D cable into the
communications port connector on the terminal device. Tighten
all retaining screws.
Note:
Be sure to attach any required adapter as discussed
previously in the paragraphs titled "Selecting the
EIA-232-D Cable."
DEFINITY Communications System
7400B Data Module
User’s Guide Page 2-11
CHAPTER 2: INSTALLATION
Connecting the DCP Cord Attach the DCP type D8W telephone cord as follows:
1.
Insert either end of the telephone cord into the connector on the
rear panel of the Data Module labeled LINE.
2.
Insert the other end of the telephone cord into the PBX wall jack.
3.
If you are using the with-phone option of the 7400B Data Module
(voice and data), install the second D8W telephone cord as
follows:
a.
Insert one end of the second D8W cord into the jack on your
7400-series DCP voice terminal.
Insert the other end of the second D8W cord into the jack on
b.
the rear panel of the Data Module labeled PHONE.
Connecting the Power
Connect the separate power supply unit to the 7400B Data Module as
supply follows:
1.
2.
Note:
An internal DIP-switch must be set correctly for
this option to work (see "Setting the Hardware
Option Switches" in this chapter). Also, if your
voice terminal has data capabilities, the data
features of the voice terminal are not supported
while it is connected to the 7400B Data Module.
Insert the output connector of the power supply into the connector
on the rear panel of the Data Module labeled “POWER.”
Caution:
Be sure that the side of the power supply cable
connector labeled “TOP” is facing upward before
inserting the connector.
Insert the AC connector of the power supply unit into an
appropriate AC outlet.
Note:
Since the 7400B Data Module does not have a power
on/off switch, the unit will power on as soon as the
power supply is connected to an active AC line.
Caution:
Make certain that the AC outlet to which you connect the
power supply is unswitched (for example, not controlled
by a wall switch or light dimmer).
CHAPTER 2: INSTALLATION DEFINITY Communications System
7400B Data Module
Page 2-12
User’s Guide
INITIAL SYSTEM CHECKS This section describes procedures for initially checking out your
hardware and any required software. It is assumed at this point that your
hardware and data communications software have been properly
installed and are ready for use.
Note:
Data communications software is required only if you are
using a PC as your terminal device. A dedicated data
terminal does not need data communications software.
Power-Up Self-Test When power is first applied to the 7400B Data Module, the unit
performs a self-test to determine that it is in working order. The
progression of the self-test is indicated by the sequential, left-to-right
lighting of the 10 front-panel LEDs.
If the self-test finds no problems, the LEDs labeled POWER/TEST and
TR will remain lit and all other LED lamps will go out.
Note:
The operation of the LEDs described here assumes that the
factory-default options are still in effect. Once certain
options have been changed, the operation of the LEDs may
differ from this description.
Your 7400B Data Module is now installed and ready for data
communications operation.
IF YOU ARE USING A PC Review the documentation for your PC and data communications
software. Be sure that you understand both well enough to get the
software running and place your PC in terminal mode.
IF YOU ARE USING A DEDICATED TERMINAL
Since there is such a diversity of functionality among the many
packages available, refer to the user’s manual of the software package
for specific details of its use. Appendix C, “Application Notes”
provides guidelines for using a few of the more popular packages with
the 7400B Data Module.
To determine whether your terminal is communicating with the 7400B
Data Module, type the following command line:
AT
[ Enter ]
Note:
The two characters of the “AT” command prefix must be
typed as either both uppercase or both lowercase. That is,
you can type either at or AT, but At or aT will not
work.
If everything is operating properly, the command should appear on the
screen as you type it, and the 7400B Data Module should respond with
OK. Refer to Chapter 5,“Troubleshooting,” for help if you are not
getting these results.
DEFINITY Communications System
7400B Data Module
User’s Guide
CHAPTER 3: FIRST TIME USERS
CHAPTER 3: FIRST TIME USERS
Page 3-1
This chapter provides some basics on 7400B Data Module operation,
describes how to use a few AT commands that are essential for most data
communications operations, and then outlines a typical on-line session.
OPERATING MODES
Character Formats
Note:
The commands for the data module are referred to as AT
commands because you must type the letters “AT” as the
first characters on the line for most commands.
Except when the 7400B Data Module is in a test mode, it is always in
one of two distinct operating states or modes: command mode and on-
line or data mode.
In command mode, the data module tries to interpret everything you
type on your keyboard as a command. In on-line mode, the data module
passes everything on as data.
While in on-line mode, typing a specific character three times in quick
succession (the factory-default escape sequence is 3 plus signs, or +++)
causes the data module to go into command mode without disconnecting
an active data call.
The operating modes, the escape sequence, and several AT commands
are explained further in Chapter 4, “Operation and Configuration.” All
AT commands are described fully in Appendix A, “AT Commands.”
In this context, character format refers to the form a character may take
locally, between the 7400B Data Module and your terminal device. The
elements that make up character format are often referred to as
communication parameters. Formats supported by the 7400B Data
Module are shown in Table 3-1.
Data Bits
Parity Stop Bits
7 even or odd
7
8
mark or space
none
TABLE 3-1 CHARACTER FORMATS
1
1
1
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DEFINITY Communications System
7400B Data Module
User’s Guide
All of these parameters may be changed on the local terminal device as
needed. The 7400B Data Module will adjust to match the speed and
parity of the local terminal device.
If you connect to a remote system and your screen shows a series of
nonsense characters (also referred to as "garbage"), chances are that you
need to adjust speed or parity.
For more information on configuration, see Chapter 4, “Operation and
Configuration.”
ESSENTIAL AT COMMANDS
Note: This section pertains mostly to dedicated terminals, since
many data communications packages for PCs may not allow
you to send AT commands directly to the data module.
This section provides a basic description of the most commonly used
AT commands. These few commands are all you will need for
completing many data communications tasks. In a later section titled
“Sample On-Line Session,” presented at the end of this chapter, you
will enter the commands manually from your terminal keyboard.
Note:
If you are using a PC with software that permits command or
script files, you may create files to perform automatic log in
for devices that you plan to communicate with frequently.
In this case, the commands used are typically not direct AT
commands, but function commands defined by the software
package. For more information on PC software, refer to
Appendix C, “Application Notes.”
Table 3-2 describes the subset of AT commands you will need for the
on-line session at the end of this chapter. For a complete description of
all AT commands, refer to Appendix A.
Note:
Except where otherwise noted, press
AT
command lines.
[ Enter ]
to complete all
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User’s Guide
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AT Command
AT
D
A/
Description
The command prefix that must be typed as the first two letters of
all AT commands except +++ and A/. This prefix gets the
AT
tention of the data module.
Note:
The characters of the AT prefix must both be typed in
either uppercase or lowercase letters (AT or at will
work, but At or aT will not). Typing a space between
the AT prefix and the next command on the line is
optional, but do not separate the two letters “AT” with
a space.
The Dial command. This command follows the AT and precedes
the number that you wish your data module to dial. For example:
atd71204
Note:
[ Enter ]
Other commands may precede the D command, but
any characters following it will be interpreted as part
of the number that is to be dialed.
The redo or Again command. This is one of the two commands
that does not require the AT prefix. To repeat the previous
command line exactly, type A/ without pressing [ Enter
].
(more)
TABLE 3-2 AT Command Subset
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DEFINITY Communications System
7400B Data Module
User’s Guide
AT Command
+++
O
H
Description
The escape character sequence. This is one of the two
commands that does not require the AT prefix. Once
you have connected to the remote device, your data
module assumes the on-line mode of operation. If you
need to return to the command mode, leave the keyboard
idle for at least one second, and then type +++ without
pressing
[ Enter ].
Within a few seconds, the data module
will respond with OK, signifying that it has entered the
command mode and is waiting for you to type a
command.
Whether OK is returned or not depends on the setting of
certain parameters. If the factory-default settings are in
effect, OK should be returned.
The return to On-line command. After using the +++
escape sequence to enter command mode, you can type
ato
and press
Note:
[ Enter ]
to return to on-line mode.
This command will not work if you have
disconnected the data call.
The hang up or disconnect command. After using the
+++ escape sequence to enter command mode, you can
type
ath
and press
[ Enter ]
to disconnect the data call.
&F
The return to Factory-default settings command. If an
experimental change of your data module settings
produces unexpected results — and you are not sure how
to get out of the fix — type
AT&F
and press
[ Enter ].
This
will return all configuration parameters back to the
factory-default settings.
TABLE 3-2 AT Command Subset (Contd.)
SAMPLE COMMAND LINES This section presents a few sample AT command lines with
explanations of the results they will produce.
EXAMPLE 1: Dialing a number.
at d 5551212
[ Enter ]
CONNECT 2400
DEFINITY Communications System
7400B Data Module
User’s Guide
EXAMPLE 2: Dialing a telephone number outside your PBX domain with a
few other options thrown in.
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In the first line of this example,
●
AT is the required command prefix,
●
D is the dial command,
●
and the remainder of the line is the telephone number.
Note: The spaces between the commands and the telephone
number are included only for readability and are not
required. You may also insert hyphens (-) anywhere in the
telephone number for increased readability.
In the second line of this example, the data module returns a response
indicating that a connection with the remote end device has been
successfully completed at 2400 bps.
at &f d 9-555-1212
[ Enter ]
BUSY
In the first line of this example,
at
is the required command prefix,
●
●
&f tells the data module to restore the factory-default configuration
parameters,
●
d
is the dial command,
●
9 represents the access code required to dial a number outside your
PBX domain,
●
and the remainder of the line is the telephone number.
In the second line of this example, the data module indicates that it detected a
busy signal.
EXAMPLE 3: Using a time saver.
A/
The A/ command tells the data module to repeat the last command line
exactly. If, as in the previous example, you had issued the command to dial a
number and the data module returned the message BUSY, you could type the
A/
command to try the number again.
Note:
The A/ command must be the only command on the command
line, and you do
not
press
[ Enter ]
to complete the line.
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7400B Data Module
User’s Guide
EXAMPLE 4: Changing data options.
A SAMPLE ON-LINE SESSION
Starting the Session
at el &d2 s0=5
[ Enter ]
This command line is a command sequence that sets up the 7400B Data
Module to automatically answer incoming calls. The commands set the
following parameters:
●
AT is the required command prefix,
●
e1 causes characters entered from the keyboard to be echoed to the
screen while in command mode
●
&d2 causes the data module to hang up the call when the local
terminal turns off DTR
●
s0=5 causes the data module to enter automatic answer mode and
answer incoming calls on the fifth ring.
This section outlines how to perform a simple on-line session using the
AT commands described in this chapter. For more information about all
AT commands, see Chapter 4, "Operation and Configuration" and
Appendix A, “AT Command Set.”
The following is a sample data call to a fictitious bulletin board service.
If you know the number of a "real" bulletin board service, you might try
an actual log on by using that number and following the suggestions in
this session.
Possible Display Problems
at d 9-555-7575
[ Enter ]
CONNECT 1200
The D command is used to dial the number of the bulletin board. Since
the connection was made successfully, the data module responded with
a message that says the remote end connected at 1200 bps.
The remote end may do nothing until you press a particular key a few
times, usually [ Enter
]. Typical of many data communications application
programs, this sometimes required input lets the remote end determine
whether you have connected with the correct communications
parameters in effect.
If the response from the remote end is unintelligible “garbage,” chances
are that the speed or parity bit selection is incorrect. In this case,
assuming that your terminal device allows, the parameters may be
corrected without disconnecting the call. Otherwise, you must
disconnect, correct the parameters, and then try the call again.
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Another possible problem is that the remote end response contains
normal words mixed in with strange characters, many of which are left
brackets ([). This usually indicates that the remote device is sending
ANSI display control sequences, and your terminal does not recognize
them (ANSI stands for American National Standards Institute).
On a PC, this can generally be remedied by first disconnecting the call,
editing the PC’s CONFIG.SYS file to include the line
DEVICE=ANSI.SYS
rebooting the PC, and then trying the call again. (For a log off
procedure, see the alternative method under “Disconnecting a Data
Call,” below.)
Note:
If the terminal device is not a PC, or the suggested remedy
does not seem to solve the problem, and then you will need
to consult the documentation for your dedicated terminal, or
for your PC and any software involved.
Disconnecting a Data Call Most remote systems will have a command or menu selection for
logging off. When you select the appropriate means, the remote system
will usually disconnect or hang up. The PBX will disconnect from the
call and, after a moment, the data module will send the following
message to your display:
NO CARRIER
Alternatively, you can use the following log off procedure:
Selection: +++
OK
The prompt Selection: is simply a representation of how the remote
system might ask you for your next command or menu selection. Type
the escape sequence (default is
+++)
but do
not
press
[ Enter ].
When the data module responds with OK, type the command line:
ath
[ Enter ]
The PBX will disconnect from the remote end device, and the 7400B
will send the OK message to the terminal display.
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