User Manual

AS4000 Operations and Maintenance
Section
605-0000-431
3
. Issue 1.6. Date3/2/99
Page 7 of 22 © Copyright Airspan Communications Corporation 1999
2.1.3. Loss of Frame Alignment
Message: ‘Tributary Unit: Frame Alignment Lost’
Source: 2Mbit/s Input to the CT modem shelf.
Fault Condition: Frame pattern in the 2Mbit/s signal to the CT modem shelf is
corrupted.
Likely Cause: a. Fault in the exchange or transmission equipment.
Consequential Effect: a. All active calls will be dropped..
b. Call in progress LEDs on the CT modem card will be off
irrespective of the call state.
c. Due to the loss of network clock, there will be a single burst of
poor BER messages from the CT Modems when the system
changes over to the internal clock source.
Repair Actions:
The fault is the result of the failure of the preceding transmission network or exchange and the
supervisory systems for these need to be checked for alarm.