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8. Troubleshooting
9128-A2-GB20-80 September 2002
8-31
Send Line Loopback
The remote Line Loopback (LLB) up and down codes are in-band codes that allow
control of a remote device. The LLB Up code invokes a line loopback in the remote
unit while the LLB Down code terminates the remote line loopback. Network
loopbacks are defined in AT&T TR 62411.
A remote LLB cannot be started when one of the following tests is active:
Any Loopback on the same interface.
Send Pattern Test on this network interface or any synchronous data port (Port
Use set to Synchronous) assigned to this interface.
Send V.54 or FT1 Loopback, or Data Channel Loopback on any synchronous
data port (Port Use set to Synchronous) and assigned to this network
interface.
Data Channel Loopback on the frame relay link on this network interface.
Procedure
To start and stop a Line Loopback:
1. Follow this menu selection sequence:
Main Menu
→
Test
→
Network Physical Tests
2. Select the
Up
code in the Send Line Loopback row to put a remote device in
loopback.
3. To start the test, highlight
Send
under Command in the Send Line Loopback
row and press Enter. The code is sent for up to 10 seconds, or until an
acknowledgement is received from the remote end. The length of time that the
test has been running is shown in the Results column.
4. To stop the test, send the
Down
code to take the remote device out of
loopback.