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Circuit Pack Descriptions
Issue 1 December 1997 7-75
23H/23H-U OLIU Quick Reference Summary 7
Transmit Functions 7
The major transmit functions of the 23H/23H-U OLIU circuit pack are as follows:
■ Selects 12 STS-1 signals from the TSI circuit packs
■ Adds SONET transport overhead
■ Byte-interleaves and scrambles the STS-1 signals to produce an STS-12
signal
■ Modulates a laser transmitter to produce an OC-12 signal.
Receive Functions 7
The major receive functions of the 23H/23H-U OLIU circuit pack are as follows:
■ Receives an OC-12 optical signal and converts an OC-12 signal to an
electrical STS-12 signal
■ Extracts STS-12 clock and retimes the received data
■ Demultiplexes the STS-12 signal into 12 STS-1 signals
■ Extracts and processes the STS-1 transport overhead
■ Processes the STS-1 pointer and frame-synchronizes the STS-1 signals
■ Processes the receive clock and provides a loop-timing clock to the TGS
circuit packs.
Control Functions 7
Control functions are as follows:
■ Protection switching for TSI circuit packs
■ Inventory information (
CLEI
code, date of manufacture, etc.).
Maintenance Signal Functions 7
The 23H/23H-U OLIU major maintenance signal functions are as follows:
■ Inserts and detects STS-1 path AIS
■ Inserts STS-1 path unequipped signal
■ Inserts and detects OC-12 line AIS
■ Inserts and detects OC-12 line FERF
■ Detects OC-12 line failures (LOS, LOF, AIS, and BER)
■ Detects OC-12 line signal degrade BER.