EXFO FTB-8500 Series for FTB-500 - Manual (Page 449)

Expert Mode Tabs
Ethernet and Fibre Channel Application 435
Port (BERT)
Port (BERT)
Press TEST, Expert Mode, and Port.
Enable Criteria: Enable Criteria enables configuring the port (Port 1 and
Port 2 for Dual Ports on FTB-8510B) Pass/Fail threshold values. This
setting is disabled by default.
Alarms
LOS (Optical interface only): Enter the count of the seconds in which one
or more LOS alarms can occur before declaring a Fail condition. Choices
are 0 to 1800 seconds. The default setting is 0 second.