On Sun, Apr 13, 2008 at 07:57:02PM -0500, Hans L wrote: > Although the transfer of audio data over cell phone audio is very > lossy, there is at least one standard, proven way of transferring data > by phone: DTMF(http://en.wikipedia.org/wiki/DTMF).
please note though, that if you send DTMF over your mobile phone, the DTMF tone is generated by the network, _NOT_ inside the phone. Your phone is required to generate the tone, too. But that tone is only played through the ear speaker to the user, it is not sent over the voice channel. AFAIR, the DTMF key press is encoded and send over the Um (air) interface to the BTS/BSC/MSC and then in the end converted into actual audible sounds. Please see Page 22 of http://www.chu.edu.tw/~lhyen/wc/gsm.pdf for a graphical illustration how this works. -- - Harald Welte <[EMAIL PROTECTED]> http://openmoko.org/ ============================================================================ Software for the world's first truly open Free Software mobile phone _______________________________________________ Openmoko community mailing list community@lists.openmoko.org http://lists.openmoko.org/mailman/listinfo/community