EXFO FTB-8500 Series for FTB-500 - Manual (Page 259)

WIS Tabs
Ethernet and Fibre Channel Application 245
WIS RX
WIS RX
Press TEST, WIS, and WIS RX.
Error Analysis

B1 (BIP-8, Bit-Interleave Parity - 8 bits): The B1 (BIP-8) error indicates a
Section parity error by performing a routine even-parity check over all
Section bits of the previous frame of a composite signal (located in the
first STS-1 of an STS-n signal).

B2 (BIP-1536, Bit-Interleave Parity - 1536 bits): The B2 error indicates a
Line parity error by performing a routine even-parity check over all
Line bits of the LOH and STS-1 frame capacity of the previous frame of
a composite signal (located in every STS-1 of an STS-n signal).

B3 (BIP-8, Bit-Interleave Parity - 8 bits): The B3 (BIP-8) error indicates a
Path parity error by performing a routine even-parity check over all
Path bits of the previous SPE excluding the LOH and SOH.