Data over normal GSM call

[Fabian Olesen]

On Mon, Apr 14, 2008 at 3:33 AM, Fabian Olesen <firewalkerx at gmail.com>
wrote:

>
>
> On Mon, Apr 14, 2008 at 2:57 AM, Hans L <thehans at gmail.com> wrote:
>
> >
> > The standard tones allow up to 16 values to be represented at a time,
> > so it would be like transferring data in base16 (aka hex or 4 bits at
> > a time).  According to wikipedia, the minimum length of a tone should
> > be 70ms, which would limit data transfer to roughly 56 bits/second.
> > Of course this is very slow and unusable if you are thinking in terms
> > of web browsing, but could be useful for transmitting small amounts of
> > data such as URIs or other connection information(an IP address is
> > only 32bits).  The URIs could be accessed immediately if the receiving
> > end has a simultaneous internet connection, or saved for later.
>
>
> This could actually work
>
> But it would require that both ends have a specialised phonestack
> (openmoko fx)
> where some kind of protocol was inplemented for listening for DTMF with a
> start and stop signal,
> where the phone would know not to send the tones into the ear piece,
> so that it would not scream into the other user's ears.
>
> after a little research, i came across the Goertzel algorithm (Wikipedia
link) <http://en.wikipedia.org/wiki/Goertzel_algorithm%20>


-- 

Mvh
Fabian Olesen

----
If it moves, compile it.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.openmoko.org/pipermail/community/attachments/20080414/619a3bac/attachment.htm