I figured I'd get this on the web for patent killing purposes if I don't get
around to filing one myself:

There's a lot of neato gadgets for playing audio through the car stereos,
but most of them suck. The release of the BlackBerry VM-605 which caimed to
have an auto-scanning FM transmitter peaked my interest. Until I read about
how it actually worked, I imagined it would work like this:

* The device would listen for available FM channels.

* It would transmit a tone on each of those FM channels.

* Using the internal microphone, it would determine which channel the user's
  radio was tuned to. 

* If the user's radio wasn't tuned and turned up, it would play call audio
  through the internal speaker.

* If the call was playing through the car radio and some problem caused it
  to stop, the device would notice and switch to the speaker. 

* Perhaps there would be a 1/8 jack which could be used with a cassette
  adaptor or car stereo line-in which would work in a similar manner,
  emitting a tone which would cause the bluetooth gateway device to select
  that output if heard on the microphone. 

In fact, the new device from BlackBerry does none of this - instead it just
selects a potentially clear channel and announces it with TTS.