The EP/421 shouldn't lose communication with the computer unless it's unplugged.
Are you sure you're not meaning, losing communication with the devices attached to the EP/421?
I'd like to know the following:
1. The specs of the USB ports that the EP/421 is plugged into.
2. If there are any hubs between the USB port on the computer and the EP/421 please let me know what hub it is.
3. When you have this symptom of losing communication, please give me a screen shot of device manager and then edgeport.exe program/General tab (with the EP/421 still plugged in)
You can send this all to email@example.com (please don't respond to this forum post.