THC that controls z axis externally

I've got a plasma set up here that uses a THC controller from China, It has an INPUT of Arc Start, Up, Down, Auto. And an OUTPUT of Arc-ok, trying to use plasmac and its wanting to INPUT of Up, Down, Ark-ok. Am I missing something easy to change that out, the THC handles everything with voltage and moving the z axis using a dc motor and external interface.

Plasmac mode 2 is designed for THC's like that
linuxcnc.org/docs/devel/html/plasma/qtplasmac.html#qt_mode

From what I can tell mode 2 only works with up and down being inputs, not outputs, am I mistaken?

I expect your connections on the THC are actually outputs and the translation has been lost a bit. EG. To be connected to INPUTS.
DO you have documentation? what does the supplier say?

Here's the manual that came with it, I will say that when it's powered up I can contact the up and down pins with the ground pin and it will move up and down 

I found the manual. This is designed to control a DC motor not a stepper motor.
Its not really suited for Linuxcnc which controls Z axis position precisely.
Assuming you have the complete chinese table, I would replace the Z axis motor and gear box with a nema 23 stepper motor. If you are really lucky mounting hole positions will have been spotted.

I would then throw out the controller and THC and use a THCAD and 7i92/7i76e and let Linuxcnc manage the whole process. You will get much better results..

Hmmmm, you think theres anyway to run with what I have for the moment? trying to at get this running asap then can modify later