EXFO FTB/IQS-85100G Packet Blazer for FTB-500/IQS-600 - Manual (Page 201)

Test Results
Packet Blazer 191
Alarms/Errors

OOMFI (Out of OPU Multi-Frame Identifier) is only available for OPU4
of a mapped signal.
RX: OPU Multi-frame Identifier number are in error for at least
5 consecutive OTU frames.

PLM (Payload Mismatch) is available when OPU-PLM check box is
selected.
RX: The Payload Structure Identifier (PSI) field does not match the
expected PT for at least 3 consecutive frames.
Errors

OMFI (OPU Multi-Frame Identifier) is only available for OPU4 of a
mapped signal.
RX: Invalid OMFI word sequence detected.