If I remember right ,I've had comm problems before and after adjusting my 5volts from 4.9 to 5.1 I was able to fix problem. I've also recently had a comm problem on one where the voltage was fine. I clicked on clc and it said no response from device. I then clicked on selector and it connected, then back to clc and it communicated with clc. Kinda weird but it worked fine after that.
