To all;
I have several Redsail Laser engravers (2 x X700 and 1 x M900) and have generally had good luck with them. Two of them run on RCL320 Ruida controllers. The third one has a Ruida 6442g controller.
I recently upgraded to a Dell Latitude e7470 laptop, which worked well with the 320 controllers. When I plugged the e7470 into the 6442 controller, I found that the Touchpad on my laptop became intermittent. Took that laptop back and found that the second e7470 did exactly the same thing. I worked with Dell Support extensively to try to find a software solution to this problem, but none was available. During this time, my trusty old Dell Latitude e6430 worked perfectly without a single problem.
Dell feels that there is a noise problem between the controller and the laptop that is causing the Touchpad to hangup. The Stickpointer and an external mouse worked perfectly even when the Touchpad was frozen.
The answer was a USB port isolator, which I purchased off eBay for about $12. It completely isolates the the two devices (the laptop and the Ruida controller) from each other, but passes the data from one to the other. No more frozen touchpad.
I have posted this because I could not find any threads that detailed this problem and have appreciated all the posts that have solved problems for me. The Dell tech felt that it could be a problem with just my Ruida controller, or just an incompatibility on the Dell Motherboard. He also said that this could show up in different forms dependent upon the machine the controller is in. So, if you are having USB problems, try a USB Port Isolator.