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Circuit Pack Descriptions
Issue 1
December 1997
7-31
BBG11 3DS3 Quick Reference Summary
7
Transmit Functions
7
The 3DS3 circuit pack transmit functions are as follows:
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Receives three B3ZS encoded DS3 signals from a DSX-3
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Recovers three DS3 clocks and nonreturn to zero (NRZ) data
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Synchronizes the data signals to STS-1 signal rate
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Inserts STS-1 path overhead
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Provides three STS-1 signals to the TSI circuit packs.
Receive Functions
7
The following receive functions are performed by the BBG11 3DS3 circuit pack:
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Desynchronizes the incoming STS-1 signals
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Terminates the STS-1 paths
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Optionally checks and/or corrects P-bit parity errors
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B3ZS encodes the outgoing DS3 signals
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Pre-equalizes the DS3 signals (with line build-out) and transmits them to
the DSX-3.
Control Functions
7
The major control functions are as follows:
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Protection switching for TSI and 3DS3 circuit packs
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STS-1 path overhead processing
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Internal fault detection
■
Inventory information (
CLEI code, date of manufacture, etc.).
Maintenance Signal Functions
7
The major maintenance signal functions are as follows:
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Detects STS-1 path AIS coming from the fiber
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Detects STS-1 path unequipped signal coming from the fiber
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Inserts DS3 AIS toward the fiber and DSX-3
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Detects DS3 AIS coming from the fiber
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Inserts and detects STS-1 path yellow signal to/from the fiber
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Detects DS3 line failure (LOS and BER).