Today I did the first integration test and it works :)
My CNC machine is running LinuxCNC, originally I only had one parallel port and all the inputs where already used. I bought a cheap PCI parallel port card from Banggood and this just worked out of the box, no driver updates, no kernel re-compile, nothing.
Since the parallel port doesn't have a 5V line, I used power from one of the USB ports and connected everything using jump wires and a breadboard.
The LinuxCNC manual describes how to configure the HAL. There are a number of modes and scale settings and I not sure which I prefer yet. The video below show me experimenting with different scales and mode settings.
I need to do some re-designing of the base plate, is at the moment it is to low to fit wires, and I also like to add some mounting holes.