P-ROC (not sure what FAST have up their sleeve) will slot into Stern Whitestar, Stern SAM and Williams WPC and just replace the existing CPU board in there. It'll hook right up to the existing driver boards etc. Out of the box, on it's own, that's what it'll connect to without additional hardware. It can be used with other platforms, but then you'll need some other way of interfacing it with the rest of the pinball machine. A one-size-fits-all controller for the many variants of CPU/solenoid/lamp/switch controls just wouldn't be feasible.

So if you want to hook the P-ROC to something different, you will need some extra boards of some kind. I can speak to System 11 as I designed that interface board. The main problem with the System 11 is that the CPU, switch matrix, lamp matrix and all the solenoid drives are on the single board. You can't control the existing CPU by pretending to be an EPROM (at least nothing exists that will do that at the moment, cool idea but even if it were possible that would be really complicated and still need hardware). So you either need to bypass the CPU section of the board and hook into the various outputs, or replace the whole board. It is possible to do the former, but you end up pretty much destroying the existing board and hacking in a rats nest of wiring. There are some early threads over on pinballcontrollers where this was done.

The interface board that I designed should work fine with all Sys11 machines and Data East (as they copied the Sys11 design), so you take out the existing MPU and replace with a P-ROC and my interface board. That's what a bunch of projects are using at the moment. Not too cheap, but I don't make any profit on my board if you buy it as a kit.

I know FAST made reference to Sys11 2.0 in some old posts, but I have no idea what they're planning or when...

Cool. I didn't know Pinball Circus was going to be using the pinHeck board.