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Knowledge Base

The experience to eliminate a fault of E1 terminal

Publication Date:  2012-09-22  |   Views:  282  |   Downloads:  0  |   Author:  SU1001522602  |   Document ID:  EKB1000015835


Issue Description

A conference site can not enter the conference by E1 transmission.

Alarm Information

On the MCU operation bench, the local/far ends of this terminal are out of sync.

Handling Process

1,Do the local loopback for the terminal to eliminate terminal fault.
2,Do the E1 loopback on the MCU operation bench to eliminate E16’s hardware fault.
3,Do the physical loopback on the both sides of the DDF distribution frame, the MCU showed local/far end sync, the terminal side showed in conference, after the DDF renewed, it became abnormal again.
4,On the MCU side, exchange the receiver and transfer on the DDF distribution frame, and then the site can enter conference.

Root Cause

There are optical transceivers on the transmission path, they are very strict to the receiver and transfer even they can not overturn, this a simple but often overlook point to lose a lot of time to eliminate. We should try to overturn the receiver and transfer when E1 is out of sync, and we should do loopback from a side one step by step, don’t do loopback from the middle.