[Asterisk-Users] g729 and dtmf

[Eric Wieling]

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.