Thanks for your advice.

I forgot to mention that I had already tried a different port.

I also sort of tried a different USB cable. We don't actually have another one long enough to connect the Voice Mail system to the computer, but the Phone system is closer and connecting fine in the console so I took the cable plugged into the Voice Mail system and switched it to the Phone system, and the console still worked - so I must conclude that it's not the USB cable.

We're attempting to connect it to another computer, but are having issues getting the driver installed - the "New Hardware Found" wizard never popped up and I haven't been able to force the driver to be installed by using the Add Hardware wizard in the Control Panel. I'm not sure how we're going to deal with that - perhaps see if we can find another computer to try.

In the meantime, any other suggestions?