Well, I just decided to go the simplest route for me and that was to buy a PC with a parallel port. the PC can dual boot so I will just play with linux and mach3 to see what I can make work best for me.
Any comments on my thought process?
Thanks!
Look inside the box and see if there's anything similar to a Breakout Board. (BoB). There are lots out there for not a lot of money. They allow you easily connect a parallel port to the stepper motors, relays and limit switches.
For my CNC Router I have a:
https://www.pmdx.com/PMDX-125
which has been replaced with the:
https://www.pmdx.com/PMDX-126
which I used for my Mill Conversion.
Although expensive the up side is the USB or Ethernet Smooth Stepper plugs into the top ribbon cable connectors or you can plug a parallel port cable from a PC directly. The photos show a smooth stepper and an expansion board.
It optically isolates the inputs but expects the outputs to be connected to stepper motor drivers that have their own isolation. It also has two relays, one that could be used for coolant (mist or floor) and one to run power to the spindle.
The second port only supports some of the I/O where the rest is dedicated to PMDX special I/O cards.
It also supports the Charge Pump feature which means if the PC crashes or during boot your spindle won't come on or stay on. Major safety issue feature and supported by LinuxCNC too.
In either case it's not really all that cheap. The PMDX-126 at $174 plus about $180 for a Smooth Stepper and $10 for cables almost makes
https://www.pmdx.com/PMDX-340
at $387 more attractive since it appears to include everything although I don't know if it works with LinuxCNC and it's out of stock at the moment anyway.
I'm running the MESA 7i92H
http://store.mesanet.com/index.php?route=product/product&product_id=303
into the PMDX-126 with LinuxCNC.
MESA has a few other Ethernet based BoB units with terminal strips etc. But they are all LinuxCNC only products.
Hence I went the simple way with the parallel port option.