Just thought I'd follow up for everyone else that my tethering problem was solved when my AT&T rep said that the rate code had been entered incorrectly by them (to enable tethering). While I had tried both BB DM 6 Mobile Internet and ATT Communication Manager, he ultimately recommended using CM. Note that each of these programs installs DIFFERENT Dial Up connections--DM installs one called MOBILE , and ATT CM installs one called AT&T. And if you examine the properties of each, they have different parameters, notably the dialup number entry. I don't know the siginificance of that, if any. But since CM works, I'm now leaving well enough alone.