Hi all - I have had my D640 for about two weeks now and everytime I use it while driving, the signal drops and connects over and over again -- this only happens though in my car - not other places! The only thing I can think of is that the headset is picking up interference from radio waves in the car or something. I have sattelite radio that uses an FM modulator so maybe that adds to it. Either way, it is great to have BT when in an airport or elsewhere, but the car is a major place I use it and need handsfree so it looks like this is going back to the store ;( I liked the headset othersie, but need it to work