Transmission Interface Handling DS1 1544 kbit/s
•
A PCM path with LOF, LOS or AIS.
•
A PCM path that is "not available for synchronization" according
to parameter in RBS DB.
The synchronization of layer 1 is in one of four states:
•
Both PCM-A and PCM-B can be used as reference source.
−
PCM-A is selected as the reference source.
−
PCM-A incoming is used to synchronize PCM-A
outgoing.
−
PCM-B incoming is used to synchronize PCM-B
outgoing.
•
PCM-A can be used as reference source, PCM-B cannot.
−
PCM-A is selected as the reference source.
−
PCM-A incoming is used to synchronize PCM-A
outgoing.
−
PCM-A incoming is used to synchronize PCM-B
outgoing.
•
PCM-B can be used as reference source, PCM-A cannot.
−
PCM-B is selected as the reference source.
−
PCM-B incoming is used to synchronize PCM-A
outgoing.
−
PCM-B incoming is used to synchronize PCM-B
outgoing.
•
Neither PCM-A nor PCM-B can be used as reference source.
−
The free running oscillator is selected as reference source.
−
The free running oscillator is used to synchronize both
PCM-A and PCM-B outgoing.
The default setting for DS1 synchronization is:
•
PCM-A: "Available for synchronization"
•
PCM-B: "Not available for synchronization"
The default setting for Layer 1 synchronization is:
•
PCM-A: "Available for synchronization"
•
PCM-B: "Available for synchronization"
The parameters can be modified from OMT. The new setting is
activated instantly. Thus the updated parameters are used when the
synchronization source is selected.
33.3.4
Supervision of Transmission Faults
The supervision is initiated during restart of DXU.
204 (306)
EN/LZT 123 2697
R5A
1998-08-13
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