AT&T System 85 manual Modular Trunk Data Module Mtdm, Functional elements

Trunk Data Module (TDM)

Modular Trunk Data Module (MTDM)

Similar in appearance and function to the TDM, the MTDM is a multi-purpose data module config- ured to provide the digital switch interface to off-premises private line trunk facilities or a switched network telecommunications network. The MTDM may also serve as a conversion resource for modem pooling.

The MTDM can be configured to support the Data Call Setup, Modem Pooling, or Off-Premises Data-Only Extensions features. In addition to the standard data transmission rates supported by previous versions of the TDM (0.3, 1.2, 2.4, 4.8, 9.6, and 19.2 kbps), the MTDM supports data rates of 56 and 64 kbps for downloading and other high speed data transfer requirements.

Features

The MTDM offers the following features:

Selected rates up to 64 kbps

Asynchronous rates up to 19.2 kbps

Synchronous operation at 56 kbps and 64 kbps

Full- or half-duplex operation up to 56 kbps

Full-duplex at 64 kbps

Self-test

Automatic answer

Private line and switched modes

Physical Description

Functional elements

Main module—Comes in one version that is common to all modular modules and pro- vides the basic digital interface and protocol conversion functions.

Interface module—Provides an RS-232-C interface

Switches

ORIG/DISC

This switch is located on the front panel. It is used when originating and disconnecting from a call for test purposes.

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