I'm running both PLM2000's and PLM2000's with the ATC.

They are wonderful machines. Yes they run on DOS, but they run g-code, and g-code is pretty much g-code. The actual platform runs on DOS. but it's been seamless. The PLM2000 won't run with a USB-RS-232 adapter, due to the below mentioned invalid voltage levels.

I use FreeDOS, and it's hands-down superior to anything else I've used, or tried.

Some very important notes:

The PLM2000 is available in 2 flavors:

#1) This model of PLM2000 does NOT have the ATC (Automatic Tool Changer). It may or may not have the quick change tool holder, but that doesn't affect this version of PLM2000.exe.

#2) The other model has the ATC (Automatic Tool Changer), with specific commands in the 'F4" Manual pull-down menu, to support the ATC. The spindle has a tool-holder clamping system, as well as a tool holder assembly on the left side.

These are oldies but goodies, but you need to be aware of some 'limitations'.

These run on the original RS-232 spec, which uses +-12 volt signaling. When computer manufacturers started implementing chipsets for desktops and notebooks in the early 2000's, it dropped the signalling levels to ~ +-6 volts. Only 3 wires are used; Transmit Data, Receive Data and Ground. The PLM2000 transmit data to the computer, and all computers I've tested have no problem with received data from the mill. However, the PLM2000 will reject the lower voltage levels from the chipset version of computers. I've had success with multiple brands and models of computer made before 2002.
I'm working to 'correct' the serial levels, and will be using notebook computers with a serial and parallel port. These can be as cheap as $25.

Floppy disk drives are the norm. There are floppy disk drive emulators for <$20 that fit in and plug in to replace the floppy drive, and use USB thumb drives. It makes a thumb drive into a drive with 100 'floppies' on it.... 000 -0 99 The drives and software are easily available, and I set them up to boot on FreeDOS Floppy '000' is set up for the ATC version of software, and '001' is the non-ATC version. I also have on of the 'thumb drive floppies' set up to plug into my Windows 10 computer, and it reports it as a floppy drive A:

If you have a PLM2000 that fails initialization, try a different serial cable, or try either 'PLM2000 /P1' and/or 'PLM2000 /P2' on the command line. This starts the software and forces it to try the specified Serial Port 1 or 2.
The ATC version also uses a straight-through 25 pin DB-25 cable that connects the computers parallel port with the PLM2000 ATC port. Do not connect the ATC DB-25 to the DB-25 connector that can be on an Intellitek or LMC interface board in the computer. The PLM2000 NEVER uses any external control boxes or internals, unless it's a serial interface card, and all that I've found of those do NOT output the +-12 Volt signaling necessary for the PLM2000 mill.

If you have the ATC option and don't have the expensive tool holders, Tormach has one that will work with the spindle, but does NOT work in the ATC. I bought a couple, and manually put them in, until I was able to get several more of the LMC model.

I also have been successful in repairing an Animatics Servo controller that the PLM2000 uses.