NEC SV8500, Operation And Maintenance Manual

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CHAPTER 3 System Messages
Repair Procedure
Depending on the fault status shown in data , perform necessary repair work:
(1) Hardware Failure/Onboard Power Alarm
SDT (PA-SDTA/B) card is faulty. Replace the card with a spare by referring to Chapter 5: Replacement
Procedure of SDT Card and Optical Fiber Cable.
(2) Optical Line Failure
Diagnosis: In addition to this alarm, is the PCM Loss alarm also indicated?
YES
o
Optical line side is faulty.
Verify that the SDT card in the distant node is not placed into make-busy state. Also, perform the
light level check of the optical fiber cables.
NO
o
SDT card is faulty.
Replace the SDT card with a spare by referring to Chapter 5: Replacement Procedure of SDT Card
and Optical Fiber Cable .
(3) Abnormal MB Key Operation
This alarm is indicated when the MB key on the PA-SDTA card is turned ON, even though the MBR key
has been on the OFF side. Place the MBR key UP (=ON) and then turn ON the MB key.
(4) PCM Loss
Abnormal state is detected on the optical line side. Verify that the SDT card in the distant node is not placed
into make-busy state. Also, perform the light level check of the optical fiber cables.
(5) 52M Interface Alarm
- Frame Alignment Loss
- Receiving Section Failure
- Mistake Rate Degradation
- Sending Section Failure
- Mistake Detection
Clock synchronization with the distant node might be lost, or a trouble might occur on the optical line side.
Check the PLO cards first in both self-node and distant node. When no fault is found, proceed with the light
level check of the optical fiber cables.
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