Intercepting Audio == Freedom from Service Providers

Andreas Kostyrka andreas at
Sat Jan 13 14:39:00 CET 2007

> If your phone can receive data over a voice channel, you have less of
> a reason to pay your service provider for a separate "data package".
> This would be especially nice for someone like me who only subcribes
> to the "bare bones" plan, but still has minutes left over at the end
> of the month and has to pay $.50 for the five text messages received.
> (Sure, only useful when communicating with other OpenMoko users, but
> still a possibly useful feature.)

The problem is, that sending raw data is probably not possible. In
theory, and especially in practice (the gsm modem being a seperate
embedded hw piece), this won't work.

To seperate this out:

*) sending raw data is probably not exported from the gsm module, and
there is the question what data can be sent.

*) trying to send data via the audio channel is doomed on two counts:
first you need a software modem, and these are not free software, plus
you would need to take into account the fact that the GSM module does
apply all kinds of lossy compression on the audio data.

The question still staying, how will one access the gsm audio streams?


More information about the community mailing list