Mobile Phone Interference

[Fitbin]

We've all heard the bzz-bzz-bzz that comes over a speaker just before a mobile phone rings or a text message is received. Does anyone know which frequency / frequencies this is on? Would it be possible to transmit something in this method so that the speaker would then play it?

[8733mags]

THe bzz-bzz-bzz you hear is the cell phone communicating with the local cell areas telling them it is in their area. The cellular phone system relies on the fact that you can move around freely and the phone is nearly always available to use. The phone does this by periodically transmitting a code and the local cell phone transmitters pick this up and recognise that you are in their area.