Circuit Pack Descriptions
Issue 8.0 July 2002
7-95
Quick Reference Summary 7
Transmission Functions 7
The OC48 RCVR A/D circuit pack performs the following receive functions:
a. Receives a SONET standard OC-48 optical signal
b. Converts the OC-48 signal to an electrical STS-48 signal
c. Extracts the 2.5 GHz clock signal and regenerates the STS-48 data signal
d. Demultiplexes the STS-48 signal into sixteen 155.52 Mb/s signals
e. Extracts the SONET transport overhead bytes and sends them to the
OHCTL (TERM) circuit pack
f. Routes the sixteen 155.52 Mb/s signals to two STS-1 time slot assignment
(TSA) devices (839B5 or 839E5 OC48 RCVR A/D circuit packs only)
g. Routes sixteen 155.52 Mb/s signals to the service DS3, STS1E, and/or
OC3 (1.3 STD) circuit packs and one 155.52 Mb/s signal to the protection
DS3 or STS1E circuit pack
h. Passes through up to sixteen 155.52 Mb/s signals to the OC48 TRMTR
A/D circuit pack in the opposite direction in bidirectional ring applications.
Timing and Control Functions 7
The OC48 RCVR A/D circuit pack performs the following timing and control
functions:
a. Extracts a 2.5 GHz clock signal from the incoming OC-48 signal
b. Generates a 25.92 MHz timing reference signal and provides it to the TG3
(DS1) circuit packs
c. Tests the incoming 155.52 Mb/s signals for section (B1) and line (B2) parity
errors and compares the error rates to preset thresholds
d. Monitors the K1 and K2 bytes
e. Routes the 155.52 Mb/s signal for the failed service DS3 or STS1E circuit
pack to the protection DS3 or STS1E circuit pack during low speed
protection switching
f. Routes the same 155.52 Mb/s signal to the active and standby OC3 (1.3
STD) circuit packs.
g. Line switches up to eight 155.52 Mb/s signals to the OC48 TRMTR A/D
circuit pack in the same direction in 2-fiber bidirectional ring applications.
h. Allows access to the protection OC-48 high speed line (OC-48
point-to-point applications) or protection 155.52 Mb/s signals (STS-3
tributaries in 2-fiber bidirectional ring applications) for low priority traffic and
for restoration access
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