Hi Benny, Sorry for the slow reply - I'm new to mailing lists and had email settings wrong (and/or new email server had teething trouble). I have got past the crashing stage now - changed the alsa config to point at hw instead of a plug and using native toolchain to build! - but was wondering if you or anyone can help me get a bit further. If I run pjsua with ec-tail=0, then do cc 0 0, I get audio, but with a fast 'ripple' over the top. If I run it with ec-tail=0 and --stereo, then the 'ripple' is a lot louder. By 'ripple' I mean a continuous clicking, repeated at about ~5-10Hz. This sounds a little like the description of bursting on the website, could this be it? I can play back and record sound fine using samples/auddemo. Also, if I use samples/simpleua I can get very good audio going from the board to the external endpoint, but I don't get any sound back from the endpoint. Thanks for any help, John