Hello

Unfortunately my control box has the old style printer ports and I can only use an old computor with windows 98.
Just for info: Mach3 and parallel port can works on Win XP, Win7 and Win8 but only on 32 bits systems. It do not works with win10/11 with parallel port, no mater the system is 32 or 64 bits.

The answer to who supplies the best one is either CNCdrive (who make them)
Yes, and be careful, as said Neal, you can find UC100 on amazon, ebay and so one at very low price, but it is fakes ! (text in red)
https://www.cncdrive.com/UC100.html

A weakness of the UC100USB is its micro USB connector which sometimes causes connection problems. On the French forum that I regularly visit, several people had to exchange the product for after-sales service because of this problem. Even if it is a little more expensive, I would recommend the Ethernet version (UC400ETH) which does not cause this problem and, in addition, it is less sensitive to EMI. (especially for those that use a VFD spindle)

In addition, you can plug 2 breakout boards to the UC400ETH, so you can increase the number of inputs/outputs that can be used if needed.

++
David