PRI Alarm Types and Meanings (2008)

Interpreting the alarms: *IMPORTANT*
E1/T1 Line Alarms

YELLOW: remote alarm indication (RAI): The RAI (remote alarm indication) signal indicates loss of layer 1 capability at the user-network interface. RAI propagates towards the network if layer 1 capability is lost in the direction of the user, and RAI propagates toward the user if layer 1 capability is lost in the direction of the network.  The  PBXtra  has detected a loss of signal from the carrier's side.

RED: Loss of signal (LOS): The equipment shall assume "loss of signal" when the incoming signal amplitude is, for a time duration of at least 1 ms, more than 20 dB below the nominal amplitude. The equipment shall react within 12 ms by issuing AIS.  The  PBXtra  has detected a loss of connectivity to the smart jack supplied by the carrier, but this can be caused by misconfiguration of the server.