Hi,

So, big picture, my current old computer is actually converting the g-code and creating the signals needed by the stepper motor controllers, etc. This is passed through the parallel port wires to the bob and distributed to the relevant controllers and devices.

To switch to USB or ethernet for use on a laptop, we move the signal creation to a new device, the suggested motion controllers. This receives the commands and creates the relevant signals (thus less noise). These signals are then passed on to a bob and the rest is the same.
Yes, that is a good summation. What you may not know, nor will you until you try, but a USB or Ethernet connected motion control board is light years ahead of a parallel port, much smoother
and capable of much higher resolution, and your PC will run just that much sweeter as it does not have to generate pulse streams, which is a PC shortcoming.

I proposed the circuit so that you could still use your C10 BoB, and thereby save some money rather than buy an MB3. The Anaspeed circuit of the MB3 is very similar to what I have proposed, namely that its analogue output is isolated.
The MB3 has an adjustment on it so it could probably be tuned to 0V-9V to match your controller. The MB3 is itself around $200USD, so its not cheap, but I think fair value. My own home brew BoB cost about the same
and is in many respects very similar to the MB3. The other advantage of the MB3 is that its fully developed to use all the IO of the ESS, all 51 inputs and outputs. You can increase the functionality of you machine with
more inputs and outputs to your hearts content, whereas your C10 is likely maxed out as is.

If you get really stuck and just cannot afford an ESS/MB3 combination, let me know I could make a little circuit board and populate and test it and send it to you, it would be the size of a matchbox,
and about $25 plus postage.

Craig