Think this was answered in another post, - but you know when you press a number on a phone (not a cell-phone), and it makes a tone? This means that a number = a tone.
The idea of a tone-dialer is, that you put a sequence of numberes into the dialer, and it will play the individual tones for each number... You can then use you gp32 to dial a particular number, by holding it up against the phones microphone.
hope it you understood what I meant.