Alcatel-Lucent 9500 MXC User Manual page 491

4
A silent transmitter switch is designed to prevent an undetected transmit failure from causing a link to go
down indefinitely.
3DB 23063 ADAA - Rev 004 July 2007
• A subordinate space diversity link operates independently of the ring operation.
Specifically, a wrapped ring link does not inhibit normal 1+1 operation of the
space diversity link.
Switch Management Heirachy: SD + SD Subordinated Links
Figure 8-1.
RING
Space
Diversity
RAC RAC
Switch Management Heirachy: SD + 1+0 Link
Figure 8-2.
RING
Space
Diversity
RAC RAC
A ring wrap occurs when the path provided by the space diversity link fails, or a
Tx or Rx online switch event occurs on the space diversity link, or both space
diversity receivers trigger a demodulator not locked alarm.
• Normal space diversity online Tx and/or Rx switching remains enabled when
the ring is wrapped.
• A silent transmitter switch
path-fail alarm, and the link has been wrapped for not less than 5 seconds.
• If the link failure is due to a path fade, the silent transmitter command from
the far-end(s) will not be received at the local end(s), meaning no Tx switch
will occur.
• If the link failure is due to a Tx failure, the silent transmitter command from
the far end will initiate a switch to the standby Tx at the local end (the
secondary RAC is the default standby Tx).
Space
Diversity
RAC RAC
RAC
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is initiated when both far-end receivers are in
9500 MXC User Manual
Vol. IV-8-9