DEFINITY Enterprise Communication Server Release 9
Installation and Maintenance for Survivable Remote EPN
555-233-121
Issue 2
November 2000
SREPN Maintenance
2-16Maintenance procedure
2
EI interactions
Although complex to troubleshoot, the following two interactions with EI circuit
packs may be present:
■ Alarms logged against an EPN that involve an Expansion Interface circuit
pack acting as the Expansion Archangel
■ EI and Tone/Clock synchronization interactions. Synchronization is
involved in the link between two active EI circuit packs or between an
active EI circuit pack and an active SNI circuit pack. If the frequency of the
clock is out of the specified range (“out of spec”), an EI fiber link can go
down.
— The EI circuit pack reports slip errors if synchronization is not
operating properly.
— Examine the EI circuit packs as a possible cause when diagnosing
synchronization problems.
For both topics, refer to the EXP-INTF section in Chapter 9 of
DEFINITY ECS
Release 9 — Maintenance for R9r
.
Testing the TN2301 function and wiring
If the SURVIVE MODE ON LED does not turn on when the PNC A and B links are
down, then the TN2301 (SRSwitch) does not detect the SRCntrl and SRCntrlRtn
signals (see ‘‘110 block cross-connect pins’’) from the Maintenance circuit pack
(TN775C). Possible causes are the
■ Maintenance circuit pack’s relay not closing
■ TN2301 detection circuit malfunctioning
■ Wiring between the SRSwitch (TN2301) and the Maintenance (TN775C)
circuit packs is incorrect.
To verify the detection circuit and wiring:
1. Momentarily short the cross-connect pins 45 and 46 on the EPN Aux wall
field. See ‘‘110 block cross-connect pins’’.
This should force the TN2301 to switch to Survive mode.
2. If the red SURVIVE MODE ON LED still does not light, verify the wiring.
3. If the wiring is good, replace the TN2301 circuit pack. See ‘‘Replacing the
TN2301 circuit pack’’.
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