AT&T System 85 Telephone User Manual


 
7400B and 7400B Plus Data Module
8400B Plus Data Module
Like the 7400B Plus data module, the 8400B Plus Data Module is a full-duplex asynchronous,
data module that provides for simultaneous voice-data communications at the desktop over stan-
dard twisted pair wiring. However, it has been designed explicitly to work, in the linked mode,
with 2-wire DEFINITY Digital Communications Protocol (DCP) circuits. That is, this data module
is a data service link between a Data Terminal Equipment (DTE) device, a 2-wire voice terminal
such as the 8400-Series voice terminals, and an AT&T DEFINITY Communications System
G3V2 or later switch.
At the desk, the 8400B Plus data module provides asynchronous communication speeds ranging
from 0.3 to 19.2 kbps. The 8400B Plus data module’s ability to emulate a Hayes compatible
modem interface makes it compatible with many standard PC communications packages that use
Hayes Command sets. In addition, the 8400B Plus data module provides a voice dial capability
that allows you to initiate voice calls from a PC using industry standard ‘‘auto-dialer’’ PC com-
munications packages.
Applications
The 8400B Plus data module can be used with the DEFINITY Communications System G3V2 or
later. The data module is used as a DCE for host access services, PC, or terminal (DTE) connec-
tivity. The PC or other terminal device is connected to the 8400B Plus data module using a stan-
dard EIA-232-D cable and, if needed, the supplied M9/F25 Adapter, an adapter which allows con-
nection from a 9-pin jack to a 25-pin jack. A DCP interface (using a D8W-type modular telephone
cord) is used to connect the 8400B Plus data module to the digital PBX.
The 8400B Plus data module may be optioned for use either with or without a telephone. In the
stand-alone case, the 8400B Plus data module supports data service only. Otherwise, the 8400B
Plus data module provides simultaneous data and voice service. The 8400B Plus works with all
DCP voice terminals that support 2-wire operations (such as the 8400-Series voice terminals), to
provide simultaneous data and voice service.
The voice dial feature allows you to dial a voice call without touching the telephone. Depending
on your communications package, you may also store telephone numbers on a PC and recall
them for dialing, log phone calls for easy billing, and take notes for later reference during a tele-
phone conversation. In addition, the 8400B Plus data module can be used to automatically turn
on the speakerphone of the voice terminal when a voice call is dialed from your terminal device.
Figure 2 shows a standard configuration in the United States, using a telephone and separate
power supply. Figure 3 shows a standard international configuration using a telephone and
separate power supply. Both the U.S. Configuration and the International Configuration may be
installed using a closet power supply as shown in Figure 4. This last installation eliminates the
need for the separate power supply.
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