Loopback Definition; Line Loopback; Figure O-1. Line Loopback Diagram - ADTRAN Total Access 5000 Deployment Manual

Total Access 5000 Business Services Deployment Guide

Loopback Definition

A loopback and Bit Error Rate Test (BERT) provide the ability to insert a known traffic pattern
and verify the error‐free performance of the circuit at given points in the system.

Line Loopback

A line loopback loops all of the received data back toward the network (DS3 payload and DS3
data). The transmitted data is the identical data that is received and is not reframed or regen‐
erated. This tests right up to the DS3 interface of the module.
The line loopback can be local to the access module and can be initiated by the 873's request
for a far end loop back.
DS-3 Facility
O-2
Line Loopback
DS3 Interface
Framer

Figure O-1. Line Loopback Diagram

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