"Martin Underwood" <a@b> wrote in message
news:crSdnafVnr7s_YXVnZ2dnUVZ8surnZ2d@plusnet...
> I've just read something which sounds far too good to be true. Is there
> any truth in it?
>
> Apparently if you accidentally lock your keys in the car, and the keys
> have a remote-control to unlock the door, it is possible to use a mobile
> phone and a second set of keys to unlock the door. You use your mobile to
> call someone else on their mobile who has your spare set. While the mobile
> call is connected, if you hold your mobile close to the car, and the other
> person presses the unlock button close to their mobile, your car will
> unlock, letting you get at the keys that you locked inside.
>
> Sounds a right load of bollocks: it suggests that the remote in some way
> communicates with the other person's mobile, then the signal passes to
> your phone, and from there to the car's locking mechanism.
>
> Does it rely on the remotes being the old sort that emit an ultrasonic
> signal rather than modern sort which use an RF signal? Can mobiles
> transmit an ultrasonic signal or are they restricted to normal 300-3000 Hz
> telephone voice signals.
>

This isn't going to work.

Some BMW's can be programmed to remember remote codes for gates etc.