NEC NDA-24300 manual Ioc Cpu Ema, Fault Detecting Function

SYSTEM MAINTENANCE OUTLINE

2.5Fault Detecting Function

The system finds a fault by its fault detecting circuit and the fault detecting program. Once a fault occurs, the system initiates a remedial action such as system changeover, make-busy setting, or restart processing by the automatic diagnosis function. This action reduces the influence of the fault so that system servicing may be minimized. The result of the process taken and the fault situation are indicated for equipment concerned.

Among the faults, those related to speech path (noise, one-way speech, speech inability, etc.) are not detectable. Since these fault reports are to be obtained from a station or operator, periodic trunk tests must be performed without failure to detect the faults related to speech path.

Figure 2-13shows an outline of fault detection, and Figure 2-14shows a block diagram of fault detection.

Fault Occurrence	Information	Example of Faults
Indication	Collection and Diagnosis

Display of

System Messages

Indication of Alarm Lamps on TOPU

IOC

CPU

EMA

Fault of line/trunk card

TSW write failure, Fault of clocks, etc.

Abnormal temperature, power supply failure, fuse blowing, etc., within the equipment frame

Figure 2-13 Fault Detection General Diagram

NDA-24300CHAPTER 2

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