[maemo-developers] [maemo-developers] RFC 2833 (OOB DTMF tones) functionality (Nokia Devs please comment)

From: Michael Wiktowy michael.wiktowy at gmail.com
Date: Mon Feb 12 02:38:56 EET 2007
Quoting claw on the Gizmo forums thread:
"We are limited by the platform in this respect. The Nokia 770/N800
operating system is currently not capable of sending RFC 2833 signals.
Nokia is aware of this shortcoming, but has not yet released an
operating system version that can do this.
(Sorry, but all we can do is ask Nokia to add this ability)"

This strikes me as kind of odd. The Maemo IM stack seems to allow for
mixed video/audio/text, why is it that the Gizmo devs seem to think
that the ITOS is incapable of this extra audio stream?

I tried to bypass this missing functionality by generating some DTMF
tones mp3s and playing them In-Band with the media player while Gizmo
was placing a call. Unfortunately, Gizmo blocked the media player from
playing the tones (while it did not block the little error tone that
accompanied the error message telling me that I couldn't play my
files). Even if it did work, I suspect that the iLBC codec would
distort the DTMF signal horribly (thus the need for RFC 2833).

Is it truly the situation that there is some missing link in the IM
infrastructure on the ITOS that won't allow OOB DTMF?

Is Gizmo or Media Player misusing the audio device such that they are
blocking each other?

I really think that this is important functionality for users as it
pretty much blocks anyone from retrieving voicemail or using automated


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