[Noisebridge-discuss] Audio data transfer protocols that work over VOIP

[Moxie Marlinspike]

You can have your VoIP link negotiate G.711, in which case you can just
shove the output of a soft modem through that.  SPEEX has some
mechanisms for shoving signaling data into the audio stream itself,
which you might be able to use for your data channel.  For any ACELP
codec, I don't think you're going to find anything off the shelf for
encoding data at a reasonable bitrate on top of it -- although that'd be
a cool research project!

- moxie

-- 
http://www.thoughtcrime.org

On 08/24/2010 10:28 PM, Sai Emrys wrote:
> For a project I'm working on, I'd like to encode some fixed data in an
> audio stream that is routed over both VOIP and POTS.
> 
> What protocols can handle the normal degredation that happens in VOIP
> & other noisy channels?
> 
> I don't care if it's low bandwidth, but it must go over lossy VOIP
> without requiring any special hardware on either side, and no special
> software that can't be easily acquired and run by anyone. It's OK if
> it requires some amount of manual processing and it's OK if it's only
> good for one-way transmission.
> 
> As an example, AFAICT standard faxes don't work well over VOIP. Morse
> code or voiced number station probably would (especially if repeated)
> but is a bit too low-bandwidth.
> 
> I'm well aware that there are better methods for data transmission;
> this isn't really meant to be practical. :-P
> 
> Thanks,
> Sai
> _______________________________________________
> Noisebridge-discuss mailing list
> Noisebridge-discuss at lists.noisebridge.net
> https://www.noisebridge.net/mailman/listinfo/noisebridge-discuss
>