t637, works great. one problem. when i in or out of the car, the bluetooth doesn't turn on/off automaticly. if i leave the bluetooth on all the time, it waste a lot of battery time. any better solution to this?

 

car charger.

I don't know, my T610 seems to be fine w/ bluetooth on all the time. I don't think the device needs to be discoverable since the phone initiates the link.

 

Leaving Bluetooth on all the time decreases your batter life by about a day or so per charge. You do not have to leave it in "discover" mode all the time though.

Its easy enough on the T637 to shut the Bluetooth off yourself when not using it.