Command Reference Guide

3Com Router 5000 Family and Router 6000 Family loopback (ISDN BRI Interface) ● 253
Command Reference
loopback (ISDN BRI Interface)
Purpose Use the loopback command to place the B1, B2, or both channels on the BRI
interface in a remote looback. This can send data from a line back to the line.
Use the undo loopback command to disable remote loopback.
Syntax loopback { b1 | b2 | both }
undo loopback
Parameters b1
Places the B1 channel in a remote loopback.
b2
Places the B2 channel in a remote loopback.
both
Places both B1 and B2 channels in a remote loopback.
Default By default, remote loopback is disabled on the ISDN BRI interface.
Example Place the B1 and B2 channels on the BRI interface in a remote loopback.
[Router-bri0/0/0] loopback both
View This command can be used in the following views:
■ ISDN BRI Interface view
Description On the ISDN BRI interface, you can place its B1, B2, or both channels in a remote
loopback.
CAUTION:
The modules with loopback-supported ISDN interfaces include 4BS (MIM), and
1BS\1BU\2BS\2BU (SIC). In addition, loopback is also supported by the fixed ISDN
interfaces on the routers, if there is any.