Guys i would like to know if it is possible to use A DTMF to send a signal to another place as in like using it to transmit as signal like a receiver. the reason i am asking this is that i want to develop a wrist alert for emergency purposes.that is if fire is detected from your house a signal can be sent from a micro controller to your wrist alert around your hand. the detection would be in the form of a vibrator.

lihle

 

I'm not sure what you have in mind by

A DTMF

DTMF is a means of modulating a signal, but has nothing to do with the transmission of anything - http://en.wikipedia.org/wiki/Dual-tone_multi-frequency_signaling

As far as your alert goes, the signaling device would have to be able to dial your receiver, which in turn would need some sort of wide area support. Think cell phone network. It might be easier to figure out how to send a text message using an autodialler.

 

We used DTMF tones and decoders to operate multiple radios from a single base station. Only the radio reciever whose tone, or tones was sent would 'unsquelch" and activate so the driver could hear the speaker at the base station. It was an older technology that had been taken to heart by commercial enterprises like ranches and delivery people. The chips were very common as they were used in every push button phone ever made back in the day, AFTER dial phones, but they may soon become obsolete because of the new "sell you lure" phones common now-a-days.