It appears to me that Mac AvantGo users are out of luck if they use USB HotSync and USB modem. AvantGo does sync and modem operations at the same time, but this does not work, at least with Mac OS 9. According to Handspring Tech Support, there is "NO WAY" you can run a USB modem and sync at the same time, because the modem monopolizes the USB drivers. I know that Mac OS 9.0.4 is supposed to be out very shortly, and Apple has said that this new version 'resolves some issues with USB devices.' Wonder if this is one of them...