This reports how many output control signals for this port appear in the paraOutSigTable, i.e., only the signals the device's software can actually assert and considers useful to monitor. An admin uses this to know how many output signal rows to expect for this port when walking the output signal table, reflecting which control lines the device can actively drive rather than just read. For example, if paraPortOutSigNumber reports 2 for a port, the admin should expect only two corresponding paraOutSigEntry rows for that port rather than a full set of every possible parallel-port signal.