DEFINITY Enterprise Communications Server Release 7
Maintenance for R7r
555-230-126
Issue 4
June 1999
Maintenance Object Repair Procedures
9-1566SYNC (Synchronization)
9
from its local oscillator. The yellow LED on the Tone-clock circuit pack flashes at
the 2.7 seconds on and .3 seconds off rate (mostly on) if timing is received from
an external source (for example, an EI circuit pack). Otherwise, if the Tone-clock
circuit pack is running on its local oscillator, the yellow LED flashes at the .3
seconds on and 2.7 seconds off rate (mostly off).
Figure 9-93. Typical Center Stage Switch Synchronization Configuration
-Two Switch Nodes, Duplicated PNC
Synchronization Troubleshooting
For both Stratum 3 and 4 operation, major and minor alarms indicate that there is
a problem with the system synchronization references. These alarms will be
resolved when the alarmed synchronization reference is restored.
Timing information is sent through both the active and standby PNCs,
but the EPNs normally derive timing from the EIs on the active PNC.
EI
EI
Tone-
Clock
Tone-
Clock
STANDBY PNC
ACTIVE PNC
TPN=30
TPN=30
TPN=3
TPN=3
TPN=2
TPN=2
TPN=1
TPN=1
EPN
EI
EI
PPN
SNC
SNI
SNI SNI
SNC
SNI SNI
SNC
SNI SNI
SNC
SNI
Switch Node 2 - A PNC
Switch Node 2 - B PNC Switch Node 1 - B PNC
Switch Node 1 - A PNC
