Specifications

CHAPTER 2: Introduction
7
2.0 INTRODUCTION
2.1 General Information
The T1 CSU/DSU product line is a high speed T1 format processor with one of three interfaces for
the DTE channel: CCITT V.35; RS-449; RS-530. It is capable of processing data at speeds from 56kb/s
to 1.536Mb/s, depending upon the format and density requirements of the application. It provides
all the framing and density requirements for data transmission across predefined network facilities,
such as ACCUNET.
The T1 CSU/DSU, because of its unique design, is able to accept timing information from any clock.
Timing information may be derived from the receive data, an external DTE, or from the internal crystal
oscillator. The T1 CSU/DSU has a series of selectable diagnostics that allow the user to quickly and
accurately troubleshoot the T1 CSU/DSU and the associated network.
The T1 CSU/DSU has a built in CSU which complies with AT&T Publication 62411. This allows the
user to attach the T1 CSU/DSU directly to the T1 Circuit. This CSU can be enabled or disabled with
a simple switch setting so that the unit can act as a DSU or as a DSU/CSU. It can also be used as a high
speed line driver to extend high speed data circuits up to 6,000 feet over shielded twisted-pair cable.
2.2 Purpose
The purpose of this document is to present to the reader the information necessary to completely
understand the operation, installation, and diagnostic procedures associated with the T1 CSU/DSU.
Chapter 1 provides the technical specifications for the T1 CSU/DSU. This chapter presents a brief
description of the unit, and its features and applications. Chapter 3 gives you the installation and initial
power-up procedures. Chapter 4 explains the interactive programming procedures associated with the
T1 CSU/DSU, and Chapter 5 gives a detailed explanation of the T1 CSU/DSU diagnostic procedures.
The T1 CSU/DSU contains all the controls and indicators necessary to configure, monitor, diagnose,
and operate the system. The front panel contains four bantam jack receptacles for network data
monitoring and test signal injection, loopback selection switches for aggregate and channel loopbacks,
and a series of LEDs that reflect the status of both the network and the DTE channel.
2.3 Bantam Jacks
The Bantam Jacks, located on the T1 CSU/DSU front panel, provide easy access to both monitor
the T1 service without interrupting the transmission of information or to inject a test signal to
exercise the T1 circuit.
To monitor the T1 service, connect a test set to the T1 CSU/DSU via the Transmit Monitor (NET TX
MON) Bantam Jack and the Receive Monitor (NET RX MON) Bantam Jack. This allows the user to
monitor the T1 service without interrupting the information flow.
To inject and receive a test signal across the T1 transmission facility, connect the test set into the IN
(NET TX IN) and OUT (NET RX OUT) Bantam Jacks. Then, place the T1 CSU/DSU in Remote
Channel Loopback. In this configuration the operator can inject a known signal and receive it back
via the network for testing purposes. This is an interruptive test. Data integrity can not be guaranteed
during this test.