Hi,
I'm unfamiliar with the UC100 but have some experience with the ESS.
My understanding is that if you use an external motion controller (any of them) then Mach interacts with the plugin associated with your
particular controller. In that situation the parallel port is inoperative. You can have one or t'other, not both.
With the UC100 operating any parallel ports cant communicate with Mach. The parallel port is much more than the external 25 pin connector,
its the software driver that allows it to communicate with Mach and its interrupt driven timer that allows it to produce a pulse stream.
If you want more IO then consider a different controller, the ESS and PoKeys devices have the equivalent of three ports worth of pins, I think
some of the UC100s larger siblings have multiple ports worth of IO too. Another alternative is to investigate Modbus. Modbus TCP would allow
any amount of IO.
Craig