Avaya S8700 Maintenance Manual page 2108

Maintenance-Object Repair Procedures
Standby SNC
Active SNC
Stratum 3
Oscillator
Phase
Locked
Loop
Clock
Generation
Circuit
Figure 8-80. SNC Functions
SNC LEDs
SNC circuit packs have the standard red, green, and yellow LEDs. The red and
green LEDs operate as usual: red means an alarm condition and green indicates
maintenance testing in progress. If the yellow LED is lit, this indicates that the
SNC is the active circuit pack, supplying timing to the carrier. In a duplex- or
high-reliability system (unduplicated PNC), the standby SNC in a carrier is unlit.
In a critical-reliability system (duplicated PNC), an SNC in a standby switch node
carrier is lit since it is providing timing for the standby carrier.
Clear Firmware-Counters Command
SNC firmware generates error reports independently of technician-demanded
tests. Therefore, the test board UUCSS clear command will not affect the error
status reported by firmware. The clear firmware-counters command will clear
every firmware-generated error unconditionally.
8-1386 Issue 1 May 2002
SNI 1e20
.
.
.
SNI 1e03
SNI 1e02
TPN
Microcontroller
Microcontroller
17
TPN Links
SNC-LINK
(aux data 2)
16
SNI (TN573)
Reference Signals
SNC-REF
Serial Channel
SNC-LINK
(aux data 1)
Clock Duplication
Control
SNC-BD
9 Clock Busses
SNC-BD
.
.
.
555-233-143