Circuit Pack Descriptions
Issue 8.0 July 2002
7-79
f. Provides the OC-12 optical signal to a lightguide cross-connect panel (or
equivalent).
g. Provides the OC-12 SONET section DCC bytes to the TOHCTL circuit
pack.
Timing and Control Functions 7
The OC12 (1.3 STD) circuit pack performs the following timing and control
functions:
a. Selects the primary or secondary 155.52 MHz timing signal from the TG3
(DS1) circuit packs
b. Provides selector circuitry for high speed protection switching
c. Performs internal fault detection and interfaces with the LNCTL circuit pack
using the board controller local area network (BCLAN)
d. Provides facility and equipment loopbacks
e. Stores inventory information (CLEI code, serial number, etc.)
f. Controls the circuit pack faceplate FAULT LED.
Maintenance Signal Functions 7
The OC12 (1.3 STD) circuit pack performs the following maintenance signal
functions:
a. Detects incoming (from the lightguide cross-connect panel) OC-12 loss of
signal (LOS), loss of frame (LOF), and signal degrade (SD) based on the
B2 error rate
b. Inserts STS-1 path AIS in each STS-1 tributary of the STS-3/3c signals
(each at 155.52 Mb/s) transmitted toward the OC48 TRMTR circuit pack(s)
when incoming (from the lightguide cross-connect panel) OC-12 LOS or
LOF is detected
c. Inserts STS-1 path AIS in each STS-1 tributary of the four STS-3 signals
(each at 155.52 Mb/s) transmitted toward the OC48 TRMTR circuit pack(s)
and in the OC-12 signal transmitted toward the lightguide cross-connect
panel when an internal fault is detected.