EXFO FTB-8510B Guia Del Usuario página 879

REI-L (Remote Error Indicator - Line):
For STS-1e: The REI-L error is declared when the M0 byte located in the
first STS-1 indicates that one or more BIP violations have been
detected.
SONET/SDH Application
M0, bits
234 5678
000 0000
000 0001
000 0010
:
000 1000
000 1001
:
111 1111
SONET Tabs
Line RX (SONET)
Indicates
0 BIP violation
1 BIP violation
2 BIP violations
:
8 BIP violations
0 BIP violation
:
0 BIP violation
229