Locate Alarm Indication Signal Alarms

Purpose

An alarm indication signal (AIS) is sent downstream to signal an error condition. There are two types of AIS alarms:

• Alarm indication signal path (AIS-P) is sent by an LTE to a downstream PTE when an LOS or LOF is detected on a upstream SONET section.
• Alarm indication signal line (AIS-L) is sent by an STE to a downstream LTE when an LOS or LOF is detected on an incoming SONET section.