USBCNC is very powerful software. The hardware interface is quite compact, for the obvious reason that not everyone has the same demands. Here some PCBS are offered to connect directly to your USBCNC CPU3 card. - Limitswitch Connectors- Allows easy connection of limitswitches with screw terminals - Solid State Relais connection- Allows easy connection of solid state relays to control 220V devices. - Puls Widener- Makes the puls longer than the standard 2us. Which allows you to use the card with 3Dstep&4Dstep/2A/4A drivers. - USBCNC->old interface- Allows client who already have our regular interface to connect this to usbcnc - 0-10V ouput- Is for those who would like to run a frequency controller to control the RPM of a milling motor