The second MarkingOnTheFly input is a differential input. The differential connection is shown in the figure below.
Figure 4: Differential connection of the MarkingOnTheFly inputs
The input can also be driven as a non-differential input, using the pins MOF_CH1_A+ and MOF_CH1_B+. Therefore the pins MOF_CH1_A- and MOF_CH1_B- must be left open.