EXFO FTB-800 Series for FTB-1 - Manual (Page 432)

Test Functions
422 FTB-700G/800 Series
OH - SONET/SDH
OH - SONET/SDH
The SONET/SDH OH page allows to modify (TX) the overhead information
to be transmitted and to view (RX) the overhead information received.
From the Test menu, tap Functions, and the OH tab.
Tap on any overhead byte in TX to modify its value.
Tap on any overhead byte in RX to see its detailed content/value.
Note: A byte in TX that has no value displayed or is grayed out, is not configurable
from the OH tab.
TX and RX Buttons (SDH)
Tap on the TX or RX button to respectively access the overhead bytes in
transmission or receive mode.
STS-1 Timeslot/STM-1 Channel
Allows to select the timeslot number for the Transport OH bytes. The
STS/AU/TU-3 overhead bytes are always for the timeslot selected in the test
configuration. Furthermore when modifying the Transport OH bytes H1 SS
bits, the modification applies to all timeslots when the test topology is
Coupled. Choices are 1 (default) to 192 (SONET) / 64 (SDH) depending on
the OC-N/STM-N interface selected.