EXFO FTB-800 Series for FTB-1 - Manual (Page 427)

Test Functions
NetBlazer 417
OH - OTN
The third SM byte (column 10) contains the following sub-fields. This
byte is configurable from 00 (default) to FF.

GCC0, columns 11-12, OTU OH: The two General Communication
Channel-0 bytes are configurable from 00 (default) to FF.

RES, columns 13-14, OTU OH: The two Reserved (RES) bytes are
configurable from 00 (default) to FF.

RES, column 15, OPU OH: The Reserved (RES) byte is configurable
from 00 (default) to FF.

JC, column 16, OPU OH:

Bits 1-6, Reserved (RES), are configurable from binary 000000
(default) to 111111.

Bits 7-8, Justification Control (JC), are configurable from binary
00 (default) to 11. Not available with ODU mux. Changing the JC
value will corrupt the payload.
Bit 1-4 Bit 5 Bit 6 Bit 7-8
BEI/BIAE BDI IAE RES