On Tue, Apr 15, 2008 at 11:17:19AM +0200, Stefano Cavallari wrote: > On Monday 14 April 2008 21:00:34 Harald Welte wrote: > > On Sun, Apr 13, 2008 at 07:57:02PM -0500, Hans L wrote: > [...] > > 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. > > This imply that there is a data channel available. Can you trasmit anything > else that DTMF? What is the bandwidth of this channel?
no, there is no data channel. The START/STOP DTMF messages are part of the layer 3 signalling messages (sent over a signalling channel that is also used for call setup/teardown). also, that signalling channel is between the MSC and the telephone. -- - Harald Welte <[EMAIL PROTECTED]> http://openmoko.org/ ============================================================================ Software for the world's first truly open Free Software mobile phone
signature.asc
Description: Digital signature
_______________________________________________ Openmoko community mailing list community@lists.openmoko.org http://lists.openmoko.org/mailman/listinfo/community