EXFO FTB-800 Series for FTB-1 - Manual (Page 294)

Test Results
284 FTB-700G/800 Series
Alarms/Errors
SyncE
Alarms

ESMC Loss
RX: No ESMC valid information frames were received for more than 5
seconds.

QL Mismatch (available when the QL Mismatch Monitoring check
box is selected)
RX: The received QL value does not match the Expected QL (refer to
page 229 or page 321).