This details are pretty simple for this control panel...
The buttons are regular arcade cabinet buttons. I get them here.. ultimark.com
The numeric keypad and powermate are both USB, so they will plug strait into the computer. The keypad will serve as a numeric input device.
I wrote my own powermate plugin in VS2008 c++. Still refining it, but it works pretty well.
The power button section will drive inputs on my CNC BOB, as well as external relay circuits. I'm going to build a small circuit to drive a small relay that drives a much larger 30 amp relay for my CNC and PC.
The rest of the buttons plug into this. The I-PAC Wiring it is simple. All buttons have a common ground, and this board has 32 inputs. It plugs into a USB port on your PC, and becomes a keyboard emulator. You press one of the buttons on the control panel and it sends a programmable keystroke to your PC. I will have to create a Mach3 screen to turn the keystrokes into Mach3 macros.
I still have some work left to do on the control panel. Right now its just buttons and a frame. I've yet to wire it. Its pretty big. its like 23" x 18" with the 15" monitor in the middle. I wanted to mount an arm to the mill but this control panel is just too big. I will probably make some kind of floor stand that I can roll out of the way when I'm not using it.