Physical Description; Figure 5-2. Block Diagram Of The 7400B Interface - AT&T Callmaster Series Reference Manual

7400B and 7400B Plus Data Module
DATA
TERMINAL

FIGURE 5-2. Block Diagram of the 7400B Interface

Physical Description

Dimensions
Note: The following measurements for the 7400B and 7400B Plus data module are approx-
imate.
Width = 7 inches
Depth (front and rear) = 8 3/4 inches
Height = 1 3/4 inches
Lights
POWER/TEST light
The red POWER/TEST light goes on when AC power is supplied to the 7400B or 7400B
Plus data module and flashes during all tests. This light, together with the DATA light,
also flashes if there is a DCP line problem.
DATA light
The green DATA light goes on during a data call. This light, together with the
POWER/TEST light, flashes if there is a DCP line problem.
5-12
RS-232C 7400B or
7400B PLUS
DIGITAL
VOICE
TERMINAL
DIGITAL SWITCH
DIGITAL
DCP
LINE
PORT