AT&T System 85 manual Series Data Service Unit DSU, Physical Description

2500-Series Data Service Unit (DSU)

2500-Series Data Service Unit (DSU)

The 2500-Series DSUs allow the user’s computer or Data Terminal Equipment (DTE) to com- municate with remotely located equipment using Digital Data Service network lines. The DSU integrates all Channel Service Unit (CSU) and DSU functions into one unit and connects between the network interface and the user’s DTE.

The DSU can operate as a point-to-point Local Area Data Set (LADS). It is used when the DCIU and external processor are more than 400 feet apart. Two DSUs per external processor are required.

Physical Description

Stand-alone Dimensions (approximate)

Width = 5-3/4 inches

Depth (front to back) = 9-5/8 inches

Height = 2 inches

Multiple Mounting Dimensions (approximate)

Width = 23 inches

Depth (front to back) = 20 inches

Height = 7 inches

Features

Full-duplex

Synchronous operation

Asynchronous operations with certain limitations when used as a LAD

Three color test and status LCD panel

Multi test functions

Two color test and Status/Fault indicator

User selectable options

Mounting

The 2500-Series DSU can be stand-alone or multiple mounted. The stand-alone units can be wall or desk mounted. The multiple mounted units are mounted in a multiple- mount housing that can house up to eight DSUs.

Operating Speeds

The 2556A, 2556B, and 2556C operate at 56 kbps. The 2596A, 2596B, and 2596C have

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