Kevin Naidoo Thank you for the response. Actually I have tried that before and it makes the audio very noise (painful for the ear) and unbearable. I have a bit better audio by processing the raw audio into g711 (alaw) format but the RTP couldn't send the packets or the stream in un choppy manner. I have perfectly working pipeline for voice conversation on laptop but not over the phone.

Hello, I just have one question. Were you able to play audio files like mp3 and wav over the phone? I have real problem with that plus it is Europe it supports puma (alaw).