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Circuit Pack Descriptions
Issue 1 December 1997 7-45
BBG12 3STS1E Quick Reference Summary 7
Transmit Functions 7
The 3STS1E circuit pack transmit functions are as follows:
■ Receives three B3ZS-encoded EC-1 signals from an STSX-1
■ Recovers three STS-1 clocks from three incoming data streams
■ B3ZS decodes and descrambles three incoming data streams
■ Frame synchronizes the incoming EC-1 signal using the STS-1 pointer
processor
■ Provides three STS-1 signals to the TSI circuit packs.
Receive Functions 7
The following receive functions are performed by the BBG12 3STS1E circuit pack:
■ Receives three incoming STS-1 signals from the TSI circuit pack
■ B3ZS-encodes and scrambles data, converts data to bipolar format, and
sends it to the STSX-1
■ Pre-equalizes the EC-1 signals (with line build-out) and transmits them to
the STSX-1.
Control Functions 7
The major control functions are as follows:
■ Protection switching for TSI and 3STS1E circuit packs
■ STS-1 path overhead processing
■ Internal fault detection
■ Inventory information (
CLEI
code, date of manufacture, etc.).
Maintenance Signal Functions 7
The major maintenance signal functions are as follows:
■ Detects STS-1 path AIS coming from the fiber
■ Inserts STS-1 path AIS toward the fiber and STSX-1
■ Detects EC-1 line failures (LOS, LOF, AIS, and BER)
■ Detects EC-1 line signal degrade BER.