Connecting to my CNC Machine

Hello, I am totally new here. I've been doing lots of research the past few weeks on getting LinuxCNC running on my ShopBot Desktop machine. I saw somebody here do the same thing under the Show Your Stuff page. I have a computer available with a parallel port through a docking station. I was going to use a Pi4 with a Mesa card but apparently there are none in the world. (Of course, just as I start getting into a new hobby!) Anyways, do I need any other hardware other than the parallel port and the board in my machine? It comes with all stepper motors and I/O installed already. 

Short answer: by a Mesa 7i96S, those are awailable.
Long answer:
Parallel port on docking station means it is a laptop, those are no good for machine control due to a lot of power saving features causing latency issues.
If it is a desktop, chances are it is through USB, so those do not work for machine control.
And if you are lucky to have a proper parallel port for a desktop, then i still can not help much as i do not know what the machines uses or how are things wired and controlled.
Could have posted some pictures and awoid reading all of the above!
Jokes aside, do post some pictures of the control box and pc with docking station.
BTW, welcome, make yourself at home.

I absolutely will post some pictures later! I work for ShopBot as a technical support man and am busy working right now. So once I have some free time I will be back.

Here's a couple pictures of my machines. I have a ShopBot Desktop 24x18" and a Handibot. The Desktop is new to me and came with no VFD or spindle so I am in the process of re-wiring it. I modified the Handibot to accept a 1hp spindle instead of the router that came with it. Both are running on the ShopBot software currently and I want to convert one or both to use with Linux.