The computer in a mini tower and there is no space for a second parallel port, but… cnc usb mach3 free download - SourceForge sourceforge. Mach4 has been in use on Industrial equipment running constantly for over a year. Mach4 is completely new software with less than 1% of the programming code in common with Mach3. Artsoft Mach3 works on almost all Windows versions and can control the motors by processing G-codes and M-codes.
