EXFO FTB-800 Series for FTB-1 - Manual (Page 308)

Test Results
298 FTB-700G/800 Series
FTFL/PT
FTFL/PT
From the Test menu, tap Results, and the FTFL/PT tab.
FTFL
Indicates the Forward and Backward ODU Fault Type Fault Location.

Fault Indication and Code displays the FTFL fault indicator message
and its code in hexadecimal format (byte 0 for forward, byte 128 for
backward).

Operator Identifier displays the received operator identifier (bytes 1
to 9 for forward, byte 129 to 137 for backward).

Operator Specific displays the received operator specific (bytes 10 to
127 for forward, byte 138 to 255 for backward).
Fault Indication Code
No fault 00 (default)
Signal fail 01
Signal Degrade 02
Reserved 03