Hi Dave & Bert,
Dave
I am standing on the back of Bert's calves looking over his shoulder,(well figuratively anyway) watching as I want/need to do the same things, and am pretty sure he wants the PC to directly control the CNC as opposed to drip feeding it. After a while it is impractical to use ancient PCs as they wear out and fail too. New PCs can be had for 4-500 USD and that beats going Salvation Army shopping. but as Bert stated the ECP and other options have been killed (Thank's Mr. Gates).
Bert,
Controller cards which have Parallel ports are still available for pci bus.

SYBA SD-PCI-1P DB25 PCI
Frys # 5370288