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Knowledge Base

DDF interconnection fault due to TALOS

Publication Date:  2012-07-24  |   Views:  451  |   Downloads:  0  |   Author:  Sabbir Ahmed  |   Document ID:  EKB0000270536


Issue Description

In BTTB GSM project, there is a link between Agrabad BSC to Nandonkanon Taxroom to Nandonkanon BSC to Nan MW. there is some E1 ADD from Agrabad BSC
to Nandonkanon BSC. BTTB Enigeer told me that all E1 was ok but in 4-PD2T-19 no. E1 is not ok. i've check in Nandonkanon BSC site in that site there is non-alarm. but Agrabad BSC site had alarm. (T_ALOS). 

Alarm Information


Handling Process

I've checked it step by step. there is 5 cause for this alarm. i know that both site E1 cable is connect with DDF. than i've checked next step. checked that Rx and Tx is
 ok or not.
at first i've given Hardware loop(in Agrabad BSC site) in DDF and after than alarm was gone. when i connect the DDF with MSC site alarm was come. than i've checked DDF by LED. in DDF
 site 1st one is Rx and 2nd one is Tx in our Optical Mux standerd. i've found it is ok. than i've checked MSC site Tx and Rx. i've found there. MSC connected their
 E1cable's Rx to our Mux's Rx and Tx is connected our Tx. than i've chaged this . than Tx is connect with our Rx and MSC Rx is connected with Our Tx. than
 service is ok.

Root Cause

I've found T_ALOS alarm in Agrabad BSC site. that means 2M interface loss of analog signal; 
Alarm cause:
(1)No 2M Payload Input;
(2)2M Interface of DDF broken off or loose;
(3)2M interface of this station broken off or loose;
(4)Fault in board;
(5) Fault in cable;