Circuit Pack Descriptions
7-104 Issue 8.0 July 2002
condition is detected at the primary node, the LNCTL circuit pack broadcasts an
automatic switch request to the board controller on the OC48 TRMTR A/D circuit
pack via the BCLAN. In the add (toward to OC-48 line) direction only, the OC48
TRMTR A/D circuit pack switches to (selects) the standby 155.52 Mb/s signal
(STS-3 tributary) from the secondary node. This completes the circuit from the
secondary node to the termination node in the ring. In Release 5 and later
releases, dual ring interworking protection switching also takes place in response
to an unprotected incoming OC-3 loss-of-signal or loss-of-frame condition.
Synchronization Protection. 7Synchronization reference switching is done by
selecting the primary or secondary synchronization reference signal from the TG3
(DS1) circuit packs. The OC48 TRMTR A/D circuit pack monitors these
synchronization reference signals and can autonomously select the primary or
secondary. The LNCTL circuit pack can inhibit this autonomous selection and
make its own selection.
Fault Detection Circuitry 7
Monitoring and Testing. 7The board controller circuit monitors all the activities on
the circuit pack. The OC48 TRMTR A/D circuit pack has an in-service and
out-of-service built-in test capability. An out-of-service test is performed whenever
the OC48 TRMTR A/D circuit pack resets or is commanded to reset by the LNCTL
circuit pack through the board controller local area network (BCLAN). In-service
testing is continuous. The board controller circuit reports errors when they occur
to the LNCTL circuit pack via BCLAN. An out-of-service test is also performed
whenever the OC48 TRMTR A/D circuit pack is inserted in a slot.
Performance Monitoring. 7The OC48 TRMTR A/D circuit pack performs the
following performance-monitoring functions:
■ Laser bias current
■ Optical transmit power.
When an incoming high speed defect or line AIS is detected by the OC48 RCVR
circuit pack, the OC48 TRMTR A/D circuit pack inserts an RDI signal in the
outgoing OC-48 high speed signal.
When an incoming low speed defect is detected from the low speed interface
circuit packs, the OC48 TRMTR A/D circuit pack inserts an STS-1 path AIS in
each STS-1 tributary of the outgoing OC-48 high speed signal.
When an internal fault is detected in the OC48 TRMTR A/D circuit pack, a line AIS
is inserted in the outgoing OC-48 high speed signal.
The OC48 TRMTR A/D circuit pack also passes through any remote defect
indicator-path (RDI-P) signals, DS3 AIS, or STS-1 path AIS to the outgoing OC-48
high speed signal.
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