>You could build your I/O card around a PIC, and control it via
>UART. In your case, the commands could look like "OUT1 ON",
>and responses "IN1 ON".

That was sort of what I had in mind, although I was considering having a p 
code interpreter on the PIC, and some form of p code generator on the PC, 
which the operator could use to write the code and download it, possibly 
with some form of interactive mode for debugging.

Depending on how complex the PC code got, it could have a PLC type graphical 
interface for the operator. 

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