There are two main alternatives if you want to use the mach3 software: First, get a parallel port card and add it to your computer and get a parallel breakout board. The planet-cnc software delivers instructions to the microcontroller on the board and the microcontroller will send out the pulse trains needed to move the machine correctly.
This software is well made and will provide great functionality. The USB controller will only work with the Planet-CNC software.
