Network Device User's Guide

Monitoring and Testing

4-21

3166-A2-GB20-10

November 1998

Starting a Payload Loopback

The Payload Loopback command (PLB) loops the received signal on the network

interface back to the network after it has passed through the framing circuitry of

the DSU/CSU. Framing CRCs and BPVs are corrected.

98-15947

CSUDSU

NETWORK

INTERFACE

ALL 1s

PLB

PORT 1

 Procedure

To perform a Payload loopback:

1. From the top-level menu screen, select Test.

2. From the Test screen, select Lpbk.

Test:

Rlpbk Lpbk Ptrns

3. From the Loopback screen, select PLB.

Loopback:

Abort LLB PLB

Test Started appears on Line 2. If a Payload loopback is already in progress,

the Already Active message appears. If an invalid combination of loopbacks

is in progress, the error message Invld Test Combo appears (see Table 4-7

for valid loopback test combinations).