EXFO FTB/IQS-88000 Series Power Blazer for FTB-2/2Pro/500/IQS-600 - Manual (Page 229)

Test Setup - Test Configurator, Timer, and System
Power Blazer 217
Signal - Signal Configuration (OTN)

Modify Tributary Slots/Port
The payload type 20 or 21 is indicated for each mapped OPU level.

Fixed Structure check box when selected (default) for OPU3, the
selection of a tributary slot will automatically select four tributary
slots from the same column, which constitute the foreground
traffic. When the Fixed Structure check box is cleared, select the
four tributary slots individually.
For... Mapped into... Tributary slot selection
ODU2 OPU3 4 OPU3
ODU1 OPU3
OPU2 a single OPU3
a single OPU2
ODU0 OPU3
OPU2
OPU1 a single OPU3
a single OPU2
a single OPU1
ODUflex OPU3 up to 32 OPU3
ODUflex/GFP-F OPU3 up to 8 OPU3