We are testing an OSN1500 using a SDH analyzer connected on a SEP1 and an E1 analyzer connected to a PQ1. We mapped a TU-12 on an AU-4 and insert the alarm TU_LOP by the SDH analyzer.
According to ITU standards, the SEP should report TU_LOP, but it is not happening.
Because we are mapping a TU-12 on an AU-4, we should enable the low order path alarm:
NE Explorer->click at the SEP board->Alarms->Low Order Path Alarm
Set the VC-12 you are using to monitor, and the alarm TU_LOP_VC-12 appears.
Because we are mapping a TU-12 on an AU-4, the TU_LOP at low order need to be monitored by a specific function.