3 4 6 Axis XHC CNC Mach4 Motion Controller Card 2000KHz USB Breakout Board MK4 When the Mach4 is working, unplug a USB cable and then plug it back in, the Mach4 can still be connected normally. - Its status indicators can indicate various statuses, including USB connection status, Mach4 connection status and running. byJuly 3, 2026