EXFO FTB-800 Series for FTB-1 - Manual (Page 437)

Test Functions
NetBlazer 427
OH - SONET/SDH

For OC-12: The M1 byte located in the STS-1 #7 indicates BIP
violations.

For OC-48: The M1 byte located in the STS-1 #7 indicates BIP
violations.
M1, bits 234 5678 Indicates
000 0000 0 BIP violation
000 0001 1 BIP violation
: :
110 0000 96 BIP violations
110 0001 to
1111 1111
0 BIP violation
M1 Indicates
0000 0000 0 BIP violation
0000 0001 1 BIP violation
: :
1111 1111 255 BIP violations