I am looking at building an IVR product with a few interesting features and need some more information about how asterisk and VoIP work and what I can get from them. As far as I can tell when I use ISDN/GSM telephone networks the DTMF information travels as data representing 'start tone' and 'stop tone' for each button pressed, it is then generated at the other end if an audio representation is required. I am interested to know if I can get access to these events 'start tone' and 'stop tone' through the dialplan or an AGI or by acting as a VoIP device. Or of course if I am completely off track and should give up now. I am looking to get the length of time a button was held down rather than that it was pressed. Thanks for any help Chris.
Chris Lee wrote:> I am looking at building an IVR product with a few interesting > features and need some more information about how asterisk and VoIP > work and what I can get from them. > > As far as I can tell when I use ISDN/GSM telephone networks the DTMF > information travels as data representing 'start tone' and 'stop tone' > for each button pressed, it is then generated at the other end if an > audio representation is required. > I am interested to know if I can get access to these events 'start > tone' and 'stop tone' through the dialplan or an AGI or by acting as a > VoIP device. Or of course if I am completely off track and should give > up now. > > I am looking to get the length of time a button was held down rather > than that it was pressed. > > Thanks for any helpISDN never does this. GSM only does this between the handset and the base-station. You only see DTMF tones from outside the GSM network itself. For fancy IVRs, beware that the timing of DTMF from a GSM handset has nothing to do with the timing of the user's keypresses. Because the base-station generates the tones, it controls their timing, and always generates rather long slow pulses of DTMF tones. Regards, Steve
asterisk-users-bounces@lists.digium.com wrote:> Does any one know if tone length is acquired by any of the asterisk > drivers? and retained/passed on within asterisk?We have some problems with RFC2833 DTMF and SIP where DTMF sent through Asterisk to another endpoint is unusable, because the length is always set to 0, while the DTMF sent to Asterisk has a normal length set in the packet. It seems Asterisk removes the length information. I think I've found the spot where to solve this, but haven't had time to investigate further. -- Andreas Sikkema Rits tele.com Scheepmakersstraat 11 3011 VH Rotterdam t: +31 (0)10 2245544 f: +31 (0)10 2245540