Appendix E: Line Status Utility

Alarm LEDs

The following alarm LEDs indicate connection problems that result from line failures:

LED Meaning

LOS Loss of Signal. Typically appears when no electrical signal is detected. (Check if the line is plugged in on the board and on the network interface).

LOF Loss of Frame (also known as Red Alarm). Appears when many frames are lost because of framing errors. The terminal is unable to synchronize on the DS1 signal.

AIS Alarm Indication Signal (also known as Blue Alarm). Transmitted instead of the normal signal to maintain transmission continuity. Also indicates to the receiving equipment that a transmission interruption occurred either at the equipment originating the AIS signal, or upstream of the originating equipment.

RAI Remote Alarm Indication (also known as Yellow Alarm). Transmitted in the outgoing direction when a terminal determines that it has lost the incoming signal.

5536 PRI RAS Communications Controller Users Guide

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