So the P-ROC is a piece of hardware that simply replaces the existing CPU & Driverboard in a WPC, and allows you to control the playfield with a set of NEW rules that the you define ? However, it is not a direct replacement for an existing board that will run the original code - like an Altek does for Bally/Stern SS machines.

That's generally it... just a couple of clarifications:

The P-ROC only replaces the CPU board (not the driver board).  It is compatible with existing WPC and later generation Stern driver boards; so you can just replace the CPU board in those machines to begin playing with custom code.

The game code doesn't actually run on the P-ROC.  Rather, it runs on a computer connected to the P-ROC via USB.  I imagine that we'll get everything running on small single board computers in the future so that the 'computer' will actually just be a little board in the backbox.

You're correct in that the P-ROC won't run original game code (neither will the computer attached to the P-ROC).  Everything must be custom.  That said, one P-ROC customer is looking into the possibility of driving the P-ROC from vPinMAME.  If that works, it will be possible to run unmodified original game code on your machine through a P-ROC.

But what I think is really cool is that if you owned an Addams Family, and someone wrote a NEW code for the game - you could simply download that code into your machine (as long as you have a P-ROC in your Addams).

Yep, I hope that we'll someday have an online repository of custom game software.  When you power up your machine, you could choose which software version you wanted to run.  If the progress we're making with our custom JD software effort is any indication, it'll be quite possible for people to create and run commercial quality game software on their machines.

- Gerry