Nortel Networks DCT1900 manual Diagnostics, Fault Counters

Technical Product Manual - DCT1900

Maintenance, Test and Maintenance Software

zAn additional fault report will be written in a third table called "Service" table.

zA general alarm is raised.

zAn alarm message is sent to the MS (Mobility only).

zA warning is generated by the CSMW software when running.

Note:

Red LED5 on the CPU board is on if there are messages in the "Info", "Fault" or "Service" tables that have not been read by means of the CSMW software.

2.2.1 Diagnostics

After T&M has concluded that the message is not an info but a fault message, T&M starts to decode, locate and verify the fault. This is done by the diagnostics module. After verification, T&M will isolate the faulty circuit to prevent usage by the system. This is done by changing its status temporarily to Test Mode (TME). When the fault cannot be verified, i.e. the fault cannot be found, the fault message in the Fault table will be completed with the status code C (cleared). This could indicate the occurrence of an intermittent fault.

2.2.2 Fault Counters

After verification of the fault, T&M knows exactly what type of fault occurred and where. A fault counter for this fault will be incremented. When the fault counter exceeds its threshold value, no further measures are taken, but immediately a GA will be activated with fault code 3 in the service table. The function of the fault counter is to count faults that can be cleared by maintenance, see Paragraph 2.2.3, but continue to re–appear, i.e. intermittent faults. When too many of these "intermittent faults" are counted within a specific time limit, an alarm shall be raised. The fault counter is halved every 24 hours to avoid generation of alarms when intermittent faults only occur occasionally.

Maint-DCT1900/R8/mw	2-3
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