i paid for g729 codec on iphone, but i can not use it - if i select just this codec to force its use, the other phone starts ringing, and when the recipient answers, the call is interrupted and finishes. When I switch to GSM codec with the same setup, the call is established correctly and is OK.
However I want to use this paid codec for saving mobile data. And yes, my SIP provider is compliant with g729 codec.
Other issue is that loudspeaker on iphone does not work - if i switch to phone loud speaker, the call is silenced or distorted (but continues) and it is not possible to swith back to the phone speaker.
My audio settings are:
Echo cancellation - Hardware
Automatic gain control - Hardware
Noise surpression sw - ON, Dialpad sounds - ON, Ring while Talking - ON