I had a MC 44 Plus, circa 1995, it used MC's WinDNC program to communicate with the computer via serial cable. You'll need to know which boards are in the controller to see what MC software you'll need. If it's an older controller then I doubt PSS will work. Multicam uses a proprietary DNC program (which changed thru out the years) to download toolpath files to the controller, there other generic DNC programs available but I've yet to find one that will work with a MC controller.
A common problem with the older MC 44 Pluses, after much use, the wires in the cable carriers would break down causing irratic machine operation. This happened to my machine, I re-wired it and removed some of the unused tubing for air and the mister that I never used anyway, made more room in the cable carriers, less tension on the wires.
Neal