363-206-305
Circuit Pack Descriptions
7-36
Issue 3 June 2000
Power Circuitry
7
The BBG4/BBG4B DS3 circuit pack receives two sources of
−
48 volts that are in
turn diode ORed, fused, and filtered before conversion to +5 volts to power the
rest of the circuit pack. A failure of the fuse or converter causes the red FAULT
LED to light.
BBG4/BBG4B DS3 Quick Reference Summary
7
Transmit Functions
7
The BBG4/BBG4B DS3 transmit functions are as follows:
■
Receives a B3ZS-encoded DS3 signal from a DSX-3
■
Recovers DS3 and NRZ data
■
Optionally checks and/or corrects P-bit parity errors
■
Synchronizes the data signal to STS-1 signal rate
■
Inserts STS-1 path overhead
■
Provides the STS-1 signal to the OLIU circuit packs.
Receive Functions
7
The following receive functions are performed by the BBG4/BBG4B DS3 circuit
pack:
■
Desynchronizes the incoming STS-1 signal
■
Terminates the STS-1 path
■
Optionally checks and/or corrects P-bit parity errors
■
B3ZS encodes the outgoing DS3 signal
■
Pre-equalizes the DS3 signal (with LBO) and transmits it to a DSX-3.
Control Functions
7
The major control functions are as follows:
■
Protection switching for BBG4/BBG4B DS3 circuit packs
■
STS-1 path overhead processing
■
Internal fault detection
■
Inventory information (
CLEI
code, date of manufacture, etc.).
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