363-206-285
Circuit Pack Descriptions
Issue 3 June 2001
7-109
Power Circuitry 7
Power for the 22F-type OLIU circuit pack is provided by two DC-to-DC converters
located on the 22F-type OLIU circuit pack. One converter supplies +5 volts and
the other supplies −5.2 volts. Both A and B −48 volt backplane busses supply
power to the converters through diode ORed circuit pack-mounted power select
circuits and a circuit pack-mounted fuse. Failure of the fuse or either converter
causes the red FAULT LED to light.
22F-type OLIU Quick Reference Summary 7
Transmit Functions 7
Major transmit functions of the 22F-type OLIU circuit pack are as follows:
■ Selects STS-1 inputs from MXRVO, DS3, STS1E, or other OLIU circuit
packs
■ Provides STS-1/VT1.5 signal cross-connections
■ Adds SONET transport overhead and, if VT1.5 cross-connected, adds
STS-1 path overhead
■ Byte-interleaves and scrambles the three selected STS-1 signals to
produce an STS-3 signal
■ Uses a laser transmitter to produce a SONET standard OC-3 optical signal
from an STS-3 electrical signal.
Receive Functions 7
The following are major receive functions of the 22F-type OLIU circuit pack:
■ Receives a SONET standard OC-3 optical signal and converts it to an
electrical STS-3 signal
■ Extracts STS-3 clock and retimes the received data
■ Demultiplexes the STS-3 signal into three STS-1 signals
■ Extracts transport overhead and, if VT1.5 cross-connected, extracts path
overhead
■ Processes the STS-1 pointer and frame-synchronizes the STS-1 signals
■ Processes the VT1.5 pointers and frame-synchronizes the VT1.5 signal, if
VT1.5 cross-connected
■ Provides STS-1/VT1.5 signal cross-connections
■ Processes the received clock and provides a reference clock to the TG
circuit packs.
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