Ericsson RBS 2106 Reference Manual page 416

Transmission Interface Handling G.703 2048 kbit/s
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Both actions are according to ITU-T recommendations G.704 and G.732.
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Two PCM paths are supported: PCM-A and PCM-B.
53.3.2 Layer 1 Synchronization
Synchronization of layer 1 is either derived from one of the incoming
PCM paths or taken from a free running oscillator. A PCM path
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cannot be used as reference source.
The synchronization of layer 1 is in one of three states:
1.
2.
3.
The default setting of PCM-A and PCM-B is:
PCM-A: "Available for synchronization"
PCM-B: "Not available for synchronization"
The parameters can be modified from OMT. The new setting is
activated immediately. Thus, the updated parameters are used when the
selection of synchronization source is performed.
53.3.3 Supervision of Transmission Faults
The function is initiated during restart of DXU.
The configuration of fault supervision can only be performed when the
AO DP (Digital Path) is in state "Disable". The reporting to the BSC is
414 (485)
Alarm indication to the remote end (A-bit in time slot 0 equal to
"1")
CRC-4 error indicator (E-bit in time slot 0 equal to "0")
Transmission of spare bits (Sa4-Sa8). The spare bits form a fixed
bit pattern (see section Operation and Maintenance below)
with LOF (Loss Of Frame alignment), LOS (Loss Of Signal), AIS
(Alarm Indication Signal) or
that is "not available for synchronization" according to a
parameter in RBS DB
PCM -A 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-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 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 B outgoing.
© Ericsson Radio Systems AB
— All Rights Reserved —
EN/LZT 720 0008 P2A
2001-11-28