NEC NDA-24300 manual System Maintenance Outline

SYSTEM MAINTENANCE OUTLINE

(a)Main Faults

Faults that may occur in the system can be generally categorized into Processor System Fault, Speech Path System Fault, Line/Trunk Fault, etc.

•Processor System Fault

The CPU alarm detecting circuit continuously monitors whether the CPU is working normally. If a fault is detected, the CPU calls up the diagnostic program, which identifies the cause of the fault and determines whether the fault is temporary or permanent. When the fault affects system operations, Active/Standby status of the CPU is changed over (provided that the system has dual configuration).

•Bus System Fault

The CPU transfers line/trunk card control information to the associated peripheral circuits via IO Bus. When a parity error is detected in the transfer data or when the required information cannot be transferred from a circuit card, the CPU identifies the cause of the fault, changes over the CPU so that system operation is not affected, and executes restart processing.

•Speech Path Fault

The CPU monitors the operating status of the TSW card, the occurrence of errors in writing data to the switch memory, and the basic clocks supplied to the speech path. Upon detecting a fault, the CPU identifies the cause of the fault, determines whether the fault is temporary or permanent, and executes required processing such as changeover of the TSW card.

•Others

The alarm detecting circuit on the EMA card continuously monitors the occurrence of faults in the PWR supply cards, such as abnormal temperatures within the equipment frame, and lights the alarm lamp on the TOPU when a fault is detected.

(b)Lamp Indications on the TOPU

When a fault occurs, the corresponding lamp on the TOPU indicates the location of the fault. For the meaning of each lamp indication, refer to Chapter 6.

NDA-24300CHAPTER 2

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