Quote Originally Posted by Doddy View Post
I think you'd find a lot of support to upgrading to Ethernet, rather than USB - there are some people here that have had problems with intermittent issues with USB in a high electrical noise environment. To this end, the admirable UC100 can be replaced instead with the EC300ETH, EC400ETH or AXBB-E devices from CNCDrive - works well with Mach3 and their own UCCNC software. These can plug directly (with suitable cable, of course) into the existing parallel interface that you have on your controller.
I've experienced a lot of problems with USB. After trying lots of methods to shield it, by far the most effective fix has been to ditch the cheap USB lead and replace it with a quality lead with gold contacts and a ferrite choke at both ends.