Guys, as Fred and the
maxim guiding help says, guiding is paused and the guide star reaquired after download. Same for phd, the imaging camera driver will block usb so no commands are sent out. How it reaquires is the question, we all see some drift and no big corrections in PHD. Beside, if you don't know what the problem is, you find out what it isn't.
Paul, if you used the mounts ascom driver you could remove the gpusb etc and use pulse guiding for all cameras. Also I've
read that button 8 on the handset adjusts tracking rate, make sure it's not sticky like Rick's handset.