1. Check the alarm inversion menu on the iManager T2000 to query whether manual alarm inversion is enabled on the port.
2. The NE is configured with automatic alarm inversion and the alarm inversion function is disabled on the port. The problem is not caused by the alarm inversion settings.
To check whether the N2SLQ16 or the optical module is faulty, replace the optical module or the N2SLQ16.
The problem persists.
Create a physical loopback of the port of the N2SLQ16.
The R_LOS alarm is cleared. This means that both the N2SLQ16 and the optical module are normal.
3. Analyze the problem again.
The problem might be caused by the TQS connected to the N2SLQ16. The R_LOS alarm reported by the N2SLQ16 might be generated due to white light transmitted by the TQS.
Create a logical outloop of the TQS.
The N2SLQ16 connected to the TQS that is not configured with services is expected to report the R_LOF alarm instead of the R_LOS alarm in the case of normal optical power input. The N2SLQ16 reports the R_LOS alarm probably because it receives white light.The initialized value of the logical chip is all zeros when the logic of the TQS does not perform framing of signal scrambling. In this case, the TQS optical module transmits white light. Loopback of the TQS means framing and scrambling initialization of the optical module. In this case, the TQS transmits random signal light instead of white light. Therefore, the downstream N2SLQ16 stops reporting the R_LOS alarm.