8. Troubleshooting

Send Line Loopback

he 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

Tinterface.

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 TestNetwork 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.

9128-A2-GB20-80

September 2002

8-31

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Paradyne CSU, DSU, 9126-II, 9128-II manual Send Line Loopback, Procedure