This attribute displays whether an Alarm Indication Signal (AIS)
alarm when state has been entered. An AIS alarm state is entered
when AIS defects have been observed and accumulated for a period
of 2.5 seconds +/- 0.5 seconds on the incoming E3 line. An AIS
defect is the occurrence of the AIS (unframed signal with a density
of zeros below a certain threshold such as defined by ITU
Recommendation G.775). If the AIS defects are intermittently
occurring, the AIS defect accumulator is decremented at a rate of 1/
10 of the incrementing rate (alarm integration ratio of 1/10), with all
measurements based on a 200 ms polling cycle.
The E3 component goes into an operational state of disabled until
the AIS alarm condition is cleared (after AIS has been no longer
detected for a period of 10 seconds +/- 0.5 seconds). As long as AIS
is detected on the incoming line, the node also transmits the far-end
SEF/AIS (in G.751 E3) or FERF (in G.832) defect indicator over
the outgoing line. The txRai attribute is set to on when transmitting
the far-end SEF/AIS defect indicator on the outgoing line.
The rxAisAlarm attribute is always set to off when the component
has been locked and left offline.