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Cisco 12006 and Cisco 12406 Router Installation and Configuration Guide
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Chapter 4 Troubleshooting the Installation
Problem Solving with Subsystems
Troubleshooting by Using the Alarm Cards
The alarm cards are installed in the alarm card slots immediately beneath the
clock and scheduler card slots. The alarm card has four primary functions:
• Redundant generation of the DC MBus supply voltage for the line cards
• Power system monitoring functions
• OK/FAIL status indication of the CSCs and SFCs
• Hardware implementation of the alarm system relay outputs and indicators
The status of these functions is displayed in the LEDs on the faceplate of the alarm
card. (See Figure 4-4.)

Monitoring Alarm Card Status

The alarm card faceplate has one pair of LEDs, labeled MBUS, that indicate the
operational status of the alarm card.
A green MBUS LED labeled ENABLED indicates that the card has been detected
by the system and is okay. A yellow MBUS LED labeled FAIL indicates that the
system has detected a fault in the alarm card.
If no faults have been detected on an alarm card, the green MBUS LED labeled
ENABLED should be on, and the yellow LED labeled FAIL should be off.

Monitoring Switch Fabric Status

If there are no faults on either CSC 0 or CSC 1, the green LED labeled ENABLED
for each CSC should be on, and the yellow LED labeled FAIL for each CSC
should be off. If the system detects a CSC fault, it turns off the green ENABLED
LED for the faulty card, turns on the yellow FAIL LED, logs a warning message
on the system console, and continues operating.
Note If the yellow LED labeled FAIL for a CSF or SFC is on, check the system console
for messages describing the fault.