I asked Boxford for SW but the don't want to sell me one. And for a price of 1100€, I can nearly twice add a motion controller like Mesa 7i76 or CSMIO IP/M with Mach3.

If you open your control cabinet, you'll find the same hardware as in my
165HMC, except you have only 3 Stepperdrivers and the controller board for it, instead of 4.
All the other parts should be the same. Maybe not always in the same position.

But the Stepperdrivers can't control with 5V TTL as today, they need 12V Cmos. For this you need a small driver with 1 or 2 little Transistors and Resistors. Unfortunately I don't know if they need a positive or negative signal to make one step.