This attribute indicates whether a Physical AIS alarm state is entered. A Physical AIS alarm state is entered when a Physical AIS defect is observed and accumulated for a period of 2.5 seconds +/- 0.5 seconds. A Physical AIS defect is declared when the incoming signal has two or less zeros in a sequence of 3,156 bits (0.5 ms). If the physical AIS defects are intermittently occurring, the physical 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. A Physical AIS alarm is cleared when the Physical AIS defect is absent for a period of 10 seconds +/- 0.5 seconds. The port goes into an operationalState of disabled until the AIS alarm condition is cleared. While the port is in the Physical AIS alarm state, the node also transmits the far-end RAI defect indicator on the out-going JT2 line.