EXFO FTB-800 Series for FTB-1 User Manual
Page 264
Test Results
254
FTB-700G/800 Series
Alarms/Errors
Errors
FAS (Frame Alignment Signal) is only available with PCM30 CRC-4 or
PCM31 CRC-4 framing.
RX: Bits 2 to 8 of the frame containing the FAS differ from 0011011.
CRC-4 (Cyclical Redundancy Check)
RX: One or more bit errors are detected in a block of data through
cyclical redundancy check.
E-Bit (CRC-4 Error Signal) is only available with PCM30 CRC-4 or
PCM31 CRC-4 framing.
RX: Bit 1 of sub-multiframe (SMF) II in frame 13 and/or 15 is set to 0
indicating a sub-multiframe error.
E2
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: Four consecutive incorrect frame alignment signals is received.
RAI (Remote Alarm Indication)
RX: Bit 11 of a framed E2 is set to “1”.
Errors
FAS (Frame Alignment Signal)
RX: Bits 1 to 10 of the first frame differ from 1111010000.