HI, quick and simple question: is it possible to use inband dtmf with g729? What I would like to do is to have sip clients connected to asterisk and a zaptel card to make pstn phone calls. My concern is to allow sip users to use digits for call destinations that do require menu actions while retaining low bandwith occupation. Tnx ! -- Best regards, Alessio mailto:afoc@interconnessioni.it
Alessio Focardi wrote:> HI, > > quick and simple question: is it possible to use inband dtmf with g729? > > What I would like to do is to have sip clients connected to asterisk and a zaptel > card to make pstn phone calls. > > My concern is to allow sip users to use digits for call destinations that > do require menu actions while retaining low bandwith occupation.You can only do INBAND DTMF with the G711 ULAW or G711 ALAW. Other codecs distort DTMF. This is not an Asterisk issue, it's a codec issue. That's why there is Out of Band DTMF.
On Fri, 2004-04-09 at 02:56, Alessio Focardi wrote:> HI, > > quick and simple question: is it possible to use inband dtmf with g729?Absolutely not.> What I would like to do is to have sip clients connected to asterisk and a zaptel > card to make pstn phone calls. > > My concern is to allow sip users to use digits for call destinations that > do require menu actions while retaining low bandwith occupation.If asterisk couldn't decode reliably a DTMF signal on the end of a network link, what makes you think it would survive a analog/digital/analog conversion on top of the lossy codec. If you search the archives, you will find that asterisk will convert the oob DTMF to inband when it goes to PSTN, or at least it is supposed to. I think there may have been some problems lately with the length of a DTMF tone played, but it is supposed to work. -- Steven Critchfield <critch@basesys.com>