Total Access 5000 Business Services Deployment Guide
O-2 65K510DEP08-1A
Loopback Definition
AloopbackandBitErrorRateTest(BERT)providetheabilitytoinsertaknowntrafficpattern
andverifytheerror‐freeperformanceofthecircuitatgivenpointsinthesystem.
Line Loopback
Alineloopbackloopsallofthereceiveddatabacktowardthenetwork(DS3payloadandDS3
data).Thetransmitteddataistheidenticaldatathatisreceivedandisnotreframedorregen‐
erated.ThistestsrightuptotheDS3interfaceofthemodule.
Thelineloopbackcanbe
localtotheaccessmodule andcanbeinitiatedbythe873’srequest
forafarendloopback.
Figure O-1. Line Loopback Diagram
DS3 Interface
Framer
Line Loopback
DS-3 Facility