I managed to find some time to study the problem of sending ringtone data to my cell phone. As I mentioned in a previous news item, I’m sick of only being able to download silly melodies as ring tones and want to be able to create some ringtone datasets that are more interesting ringing sounds. The first step towards that is to figure out how the whole thing works.
I’ve managed to code up a quick and dirty Perl program that creates an RTPL bitstring, converts it to text formatted hex data, and sends it to the phone in SMS format. At present it doesn’t really do anything useful besides providing a working example of the packet format and testing the sonic range of the phone. I’ve hard-coded a ringtone that emits sound over the entire range that the RTPL data can cover.
The next step would be to make some sort of algorithmic sound synthesizer that could generate RTPL data. If anyone wants to play with what I’ve got so far, I’ve put it up on our free software page. It should work with any Nokia phone that accepts ringtone data and perhaps other types of phones as well.