While I stood at the parts counter at Winslow BMW (Colorado Springs) I noticed a 'bulletin' about the X5 phone hookups on the wall. It said that the wiring in early X5s is incomplete for "handsfree" operation and that the in-car antenna is only spec'd for 900MHz, not 1900MHz, operation. I think that limits the phones to AT&T's dual band analog/PCS -- but not the ones that operate up at 1900MHz. I neither have the BMW phone nor do I plan to get one, so I didn't read the bulletin too carefully. If you're interested in the subject, ask your dealer. Or phone Winslow (719-473-1373) and ask them to FAX you the info.