Chapter 4: PRI fault clearing
Contents
This section contains information on the following topics:
PRI Red alarm (local alarm)
PRI Yellow alarm (remote alarm)
PRI problems
D-channel problems
PRI Red alarm (local alarm)
A PRI local alarm can indicate:
• 1.5 Mb/2.0 Mb digital transmission problems
• a PRI card fault
Under any of these alarm conditions, all 24/30 B-channels are taken out of service, and:
1. The PRI local alarm faceplate LED is lit.
2. Calls on the PRI are disconnected automatically.
3. All 24/30 B-channels are disabled.
4. After a pause of 2.5 seconds, the PRI sends a remote-alarm indication to the far-
5. The appropriate Digital Trunk Diagnostic (DTA) message is printed, and a minor
System software checks every 0-15 minutes (programmable) to see if a clock-controller or
reference-clock error has occurred.
If the 0-15 minute check finds the PRI in local alarm was a primary clock source, the software
switches the clock controller to the secondary reference.
ISDN Primary Rate Interface Maintenance
on page 17
on page 19
on page 21
end switch.
alarm is raised on all attendant consoles within the same customer group.
on page 19
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