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Circuit Pack Descriptions
7-52
Issue 3 June 2000
Power Circuitry
7
The BBG19 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.
BBG19 DS3 Quick Reference Summary
7
Transmit Functions
7
The BBG19 DS3 transmit functions are as follows:
■
Receives a B3ZS-encoded DS3 signal from a data services device
■
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 BBG19 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
■
Preequalizes the DS3 signal (with LBO) and transmits it to a data services
device.
Control Functions
7
The major control functions are as follows:
■
STS-1 path overhead processing
■
Internal fault detection
■
Inventory information (
CLEI
code, date of manufacture, etc.).
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