[J2ME] DTMF through ringtone speaker/ringtone generator? how?

[devnull]

hi there,

what i would like to do:

write a small j2me toy application that allows to dial numbers
through a landline (say PSTN) phone

putting the the phones close each other, and then letting the
application "play" the dtmf tones through the mobile "ringtone speaker".

problem:

since DTMF tones are made of a couple of frequencies played in the same
moment, i think i have these options:
1. use ToneControl; but i think it can only emit only one tone at time
2. use MidiControl and/or midi files stored in the jar; do you know any
tutorial on the subject?
3. use wav files stored in the jar file

i think option 1 is not a good candidate;

option 3 requires more memory and cannot work with phones that cannot
"ring wavs"...

option 2 is interesting , but i know nothing about polyphonic midi file
format.... forthermore, the higher frequencies needed by the DTMF
standard can be translated only on a MIDI note that is more than 1.5%
(standard tolerance) far than the correct DTMF frequency....it's about
1.7-1.8 indeed...



*what do you think?*

is there any other method to play a couple of "tunes" in the same
moment, without putting waveforms in a "sampled table"?



i would be developing this for a sony ericsson "platform 7" phone, but
the more general the solution is, the better...

(premise: i'm completely ignorant about j2me...)

thanks a lot in advance - and sorry for my horrible english

devnull ;-)

 

[David Segall]

hi there,

what i would like to do:

write a small j2me toy application that allows to dial numbers
through a landline (say PSTN) phone

putting the the phones close each other, and then letting the
application "play" the dtmf tones through the mobile "ringtone speaker".

There is an applet at
<http://www.dsptutor.freeuk.com/dtmf/ToneGenerator.html> that does
this. It uses pre-recorded .au files to play the tones. I have
converted it to a Java application that uses a database as the
telephone book. You are welcome to my code. Send an email to david at
segall dot net (the "Reply To" address of this post is invalid).