APC UPS stops PC comm

[jackman]

I'm looking for a little advice. I have a Dell XPS8300, Davis WMII station, and VWS 14.01. After some lengthy trial and error I've determined that my APC SmartUPS 750 kills the communications between the WMII and the PC. The UPS is connected using USB. The WMII is connected to a TrippLite USB/serial adapter purchased from Ambient. If I leave the UPS disconnected all is fine. If I connect the UPS to a USB port after a few hours VWS reports that it can no longer communicate with the WMII. I've tried all kinds of combinations of ports and settings to no avail.

What is also interesting is that I've experienced similar comm problems with this UPS using a different/older computer although it would not affect the WMII. This leads me to believe that the UPS has some kind of problem with its USB port. I'm certainly willing to use the UPS disconnected from the PC although I hate to give up the unattended shutdown feature. I'm wondering if anyone else has experienced a similar problem.

All replies are greatly appreciated.