EXFO FTB-800 Series for FTB-1 - Manual (Page 263)

Test Results
NetBlazer 253
Alarms/Errors
E1
Alarms
Note: Only AIS is available when the framing is set to Unframed.

AIS (Alarm Indication Signal)
RX: An unframed all-ones signal is received.

LOF (Loss Of Frame)
RX: Three consecutive incorrect frame alignment signals is received.

RAI (Yellow) (Remote Alarm Indication)
RX: Bit 3 in timeslot 0 is set to “1”.

TS16 AIS (TimeSlot 16 Alarm Indication Signal)
RX: Timeslot 16 is received as all-ones for all frames of two
consecutive multiframes.

LOMF (Loss Of MultiFrame)
RX: Two consecutive multiframes alignment signals (bits 1 through 4 of
TS16 of frame 0) is received with an error.

RAI MF (Remote Alarm Indication Multi-Frame)
RX: Bit 6 of timeslot 16 of frame 0 is set to “1”.