User manual

Chapter 1. Introduction
61202156L1-1 TDU 120e User Manual 1-3
• Fractional T1 loopbacks as defined in annex B of ANSI
T1.403-1995
• Software configurable long-haul or short-haul DS-1 port
• External alarm connector
TDU Option Modules
Table 1-1 shows a list of option modules and their
descriptions for the TDU 120e.
Table 1-1. TDU 120e Option Modules
Module Description
DSX-1
Short haul T1 interface for operation with a PBX (Terminal
Interface)
Full Drop and
Insert
Permits the dropping of data and insertion of new data into
the same DS0 time slot
This module includes a long haul DS-1 interface. It can
also be used as a second DS1 interface to provide an up
to 3 MB aggregate throughput
Nx56/64 serial
interface
Provides a V.35 serial interface in either single or dual ver-
sions
Voice interface
2/4 channel FXS/FX0/E&M
OCU DP
Interfaces to DDS or 4-wire Switched 56, dual or single
versions
DSU DP
Provides two sync or async ports (EIA-232 or V.35)
Dial backup
Allows for backup of data upon network T1 failure
U-BR1TE
Allows ISDN lines to be extended over a T1 line