363-206-285
Circuit Pack Descriptions
Issue 3 June 2001
7-73
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 clock 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.).
To Next Page
Loading...