Clearing system-detected troubles, Complete system failure, Common control trouble – AT&T System 25 User Manual
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MAINTENANCE
Clearing System-Detected Troubles
Most troubles are detected through the Alarm LED located on the Attendant
Console, the Error Log, and, in some cases, the LEDs on the circuit packs
(CPs). The following is a list of system troubles. Each item in the list is
described in this section.
Frontplane Ribbon Connector Trouble (Release 1 Only)
Emergency Transfer Unit Trouble.
Complete System Failure
A complete system failure is caused by a catastrophic failure in the Common
Control circuitry, the power supply, the backplane, or the cabinet. Refer to
the relevant procedures below in the event of such a failure. Complete
system failures are rare; most failures are of a noncritical component, such
as a port on a CP.
Common Control Trouble
Failure of a the Common Control CP (that is, CPU/Memory or Service Circuit)
is critical and requires replacement of the faulty pack(s). Failure of these CPs
can affect the entire system and may cause the Emergency Transfer Unit
(ETU) to activate.
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