Physical Description; Figure 5-2. Block Diagram Of Dtdm Interfaces - AT&T Callmaster Series Reference Manual

ISDN Asynchronous Data Module (ADM)
Digital Terminal Data Module (DTDM)
The DTDM provides a DCE interface to a DTE device that is connected to the DTDM (see
Figure 2 below) and allows the DTE to communicate with the switch through the voice terminal
and its mounting cord. Data calls and voice calls can be carried on simultaneously, or data calls
can be initiated independently of voice calls. The DTDM and the digital voice terminal integrate
data and voice into the DCP interface with the system digital switch. The voice terminal user can
continue to access all voice features while the module is active on a data call.
Addition of a DTDM allows an in-place 7403D or 7405D voice terminal to be upgraded for data
communications at low cost.

FIGURE 5-2. Block Diagram of DTDM Interfaces

Physical Description

The DTDM is contained in a molded plastic housing styled to match the associated voice termi-
nal. Status lights, switches, and controls are located on the faceplate and behind a hinged side
cover.
Dimensions
Note: The following dimensions are approximate.
Width = 4-3/4 inches
Depth (front to back) = 8-3/4 inches
Thickness = 1-1/2 inches
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