Maintenance - AT&T Network Adapter 25 Installation And Maintenance Manual

The primary maintenance objective is to detect, report, and clear troubles as
quickly as possible with minimum disruption to normal service. Periodic
system self-tests, automatic software diagnostic programs, and fault
detection hardware are several of the maintenance tools used to achieve this
objective. Most troubles in System 25 can be isolated to a replaceable unit.
The System 25 hardware is maintained as a group of independent units (that
is, maintenance objects). Each object is normally a separately replaceable
unit. Examples include circuit packs (CPs), power supplies, fan assemblies,
the Digital Tape Unit, AC Power Distribution Unit, voice terminals, lines, and
trunks.
System-Detected Errors
User-Reported Troubles.
For system-detected errors, a light-emitting diode (LED) on the attendant
console automatically lights if the error qualifies as an "alarm. " This is a
serious error. Most alarms are also indicated by LEDs on system CPs.
User-reported troubles usually result from service problems at individual
voice and data terminals and are often related to alarmed conditions.
Error records and alarms are retired either automatically or manually. After a
trouble or error has been cleared, the system retests the previously faulty
area within a variable time interval. When the error is no longer detected, the
error message and the alarm, if applicable, are retired. By entering
commands at the SAT, maintenance personnel can retire error records and
alarms manually after a problem has been fixed. Also, error records can be
accessed and listed, and some alarms can be removed through the SAT.
However, certain alarms must be cleared manually. After the error messages
have been removed from the error tables, the Attendant Alarm LED (and red
CP LEDs) will go dark unless the trouble recurs.
Note: Information contained in this part applies to the AT&T
System 25 RI VI, R1V2, R2V1 and R3V1. However, in all
cases except
CPU/Memory CP (ZTN129 [R2V1] or ZTN130 [R3]) is
referenced rather than the Call Processor CP and Memory
CP used in RIV1 and R1V2.

MAINTENANCE

in the description of CP LEDs, the
MAINTENANCE
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