Stage Desinger 50 has a midi output - so if it sends midi notes there - it should be done.
You need to connect it to your computer somehow - so you would have to buy a midi interface, or some midi audio interface.
With this solution, you will still need to concert CC midi signals - on note + velocity (when it comes to faders)
Both solutions work similarly - be it dmx in or midi in ..
MIDI is limited to 128 notes
on DMX you have 512!
The dmx control is also more accurate - because it has 256 levels - and the midi is only 128
You can buy a cheap USB midi driver - but purchase of an artnet gate with two inputs is the best solution at this point.