When the OTU board accesses light, the laser at output end is disabled.
Product

OptiX BWS 1600G
Fault Type

Protection
Optical Transponder Unit
Symptom

During the TMX test in the OptiX BWS 1600G, it is found that no light is transmitted at the transmit end on the client side of the TMX board after the fiber on the WDM side of IN port is removed. After a meter is connected to the WDM side, the client-side laser on the TMX board cannot be enabled automatically (the automatic laser shutdown (ALS) function is enabled). In this case, you have to disable the ALS function, enable the client-side laser manually, and then enable the ALS function. Then, the situation becomes normal. That is, the client-side laser is enabled automatically after a meter is connected to the WDM side of the TMX board.
Cause Analysis

None.
Procedure

When the problem occurs, make sure that there is no R_LOS alarm on the OTU board (note that the alarm may be suppressed). If there is the R_LOS alarm and the automatic laser shutdown (ALS) function is enabled, the laser at the output end is disabled.
Check whether the SCC issues a command to disable the laser or not. If yes, the ALS function cannot take effect, unless the SCC issues a command to enable the laser.
Check whether the SCS protection is configured or not. If yes, the SCC disables the laser of one board to duplicate the service. In this case, the ALS function cannot take effect.
Reference Information

If there is service on the SCS, do not enable the laser that is disabled by the SCC. Otherwise, the service is interrupted, unless the fiber from the OTU to the SCS is removed.