USB and Ethernet Mach3 motion controller PLCM-E3

[Jonathan]

Documentation isn't very clear.

Indeed...

Although this bit implies its output is the same pinout as the parallel port:

The branded software enables one to use the I/O ports of the
controller in MACH3 instead of computer built-in LPT ports. If you
were earlier using a computer LPT port to connect drivers, you will
need to disconnect the connector from the computer LPT port, connect
it to the PLCM controller and install the appropriate plug-in
for MACH3.
Each controller has at least one port completely matching the
physical LPT port.

If so that sounds like a good idea if you've already make your control box. Just plug this in between and go.

Still not liking mainly the lack of information about the interface/software/drivers but also the 100KHz limitation and only being compatible with Mach3.