Setting a Loopback for a Digital Interface

This section describes how to set the loopback for the digital interface on the U2000 Web LCT. The digital interface loopback is a commonly used way of fault location during the test and maintenance of the IF boards. By performing the loopback at a digital interface, the system can determine whether the IF interface and the fibers/cables connected to the IF board are normal and whether the IF board service processing module and the cross-connect board are normal.

Context

The digital interface loopback includes the outloop and inloop.

When an outloop is used, the IF service received by the NE is returned at the IF interface. See Figure 1. An outloop can be used to test the IF interface and the fibers/cables connected to the IF interface.
Figure 1 Outloop
When an inloop is used, the IF service transmitted by the NE is returned to the cross-connect board at the IF interface. See Figure 2. An inloop can be used to test the IF board service processing module and the cross-connect board.
Figure 2 Inloop

NOTICE:

As a loopback interrupts services, it is only used for fault location and must be released after the fault is removed.

Procedure

In the NE Explorer, select an IF board and choose Configuration > Digital Interface from the Function Tree.
Select By Function. Select VC4 Loopback.
Choose a digital interface from the list and double-click VC4 Loopback to select the loopback mode.
Click Apply and the Confirm dialog box is displayed.
Click OK. A prompt is displayed indicating that the operation is successful.
Click Close.