Hi paulus.v,
have checked the couplers - working fine. 24 Volts the input swing, 5 V the output swing. Detected with mach3 a page where the USB-Contoller is checked. Shows, besides other things, the behaviour of the inputs of the USB-Board. There you can see the switches work!?
Now whats preventing mach3 not to read this!?
Maybe I contact the mach3-provider?
A baffled novice