Seems that with actual windows audio api is not possible to select "capture-dev" and "playback-dev", because Windows (7 in my case) allways set the play and record devices defined as default in system. I have been able to change this default devices even in midle of calls, but then I change this, all the audio change (even all system audio, etc.) But desktop Windows systems has another "Default Communication device" diferent that "system default audio device", that its supposed for softphones... Can be possible to make pjsua play and record over this Windows Communication device? So, with this we could have i.e all audio default over speakers, and pjsua on plantronics usb (I have been abble to change the "default communications device play and record" in real-time) Someone post somethig about this, a log time ago, but I dont see any clue of how to make this to work.