363-206-305
Circuit Pack Descriptions
Issue 3 June 2000
7-73
For all 22-type OLIUs, both A and B
−
48 volt backplane busses supply power to
the converter through diode ORed circuit pack-mounted power select circuits and
a circuit pack-mounted fuse. Failure of the fuse or converter causes the red FAULT
LED to light.
22-Type OLIU Quick Reference Summary
7
Transmit Functions
7
Major transmit functions of the 22-type OLIU circuit packs in the FiberReach
application are as follows:
■
Select STS-1 inputs from main OLIU circuit packs
■
Provide STS-1 signal cross-connections
■
Add SONET transport overhead
■
Byte-interleave and scramble the three selected STS-1 signals to produce
an STS-3 signal
■
For 22D-U, convert the STS-3 electrical signal to an IS-3 optical signal and
transmit it over the fiber
■
For 22F-type and 22G-type, use 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 22-type OLIU circuit packs:
■
For 22D-U, receive an IS-3 optical signal and convert it to an electrical
STS-3 signal
■
For 22F-type and 22G-type, receive a SONET standard OC-3 optical signal
and convert it to an electrical STS-3 signal
■
Extract STS-3 clock and retime the received data
■
Demultiplex the STS-3 signal into three STS-1 signals
■
Extract transport overhead
■
Process the STS-1 pointer and frame-synchronize the STS-1 signals
■
Provide STS-1 signal cross-connections.
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