I'm working on a SIP softphone but I got the following problem and I have no idea how to solve it: During an audio call, PMCA codec is used primarily. How to setup codec priority to achieve PCMU will be used during the call? I use Windows 7, C# (Visual Studio), Ozaki C# SIP library (http://www.voip-sip-sdk.com) and the following type of codecs: PCMA, PCMU, iLBC. I hope that one of the community have any idea. Thank you very much for any help.