EXFO FTB-8500 Series for FTB-500 - Manual (Page 262)

WIS Tabs
248 FTB-8500 Series and FTB-8120NGE/8130NGE
WIS OH RX
WIS OH RX
Allows verification of the transport overhead information received.
Press TEST, WIS, and WIS OH RX.
Binary
Allows displaying all overhead values either in binary (when enabled) or
hexadecimal (when disabled). This setting is disabled by default.