EXFO FTB/IQS-88000 Series Power Blazer for FTB-2/2Pro/500/IQS-600 - Manual (Page 293)

Test Results
Power Blazer 281
Alarms/Errors
Error

BPV (Bipolar Violation), available with DS1 and DS3, pulses of the
same consecutive polarity were detected, in violation with the bipolar
signal format.

BPV/CV (Bipolar Violation/Code Violation), available with STS-1e and
STS-3e, pulses of the same consecutive polarity were detected, in
violation with the bipolar signal format.

CV (Code Violation), available with E1, E3, E4, STM-0e, and STM-1e,
pulses of the same consecutive polarity were detected, in violation
with the bipolar signal format.

EXZ (Excessive Zeros):
For DS1 with AMI Line Coding, more than 15 consecutive bit periods
with no pulses have been received.
For DS1 with B8ZS Line Coding, more than 7 consecutive bit periods
with no pulses have been received.
For DS3, more than 2 consecutive bit periods with no pulses have been
received.