Hi, Thanks so much for Freeswitch and Gsmopen! I'm loving it! I'm having an issue with incoming calls to a Gsmopen endpoint (E160). Sometimes I hear a strange sound before my IVR recording starts. Here are some examples: http://hartmanncomputer.com/2013-03-03-11-10-17_501x.wav http://hartmanncomputer.com/2013-03-03-11-12-02_501x.wav Although the two examples are pretty consistent, the sounds, when they happen are generally not. Sometimes it's just a hiss, then maybe another time it will be more of a screech. I'm using Ubuntu 12.04-amd64. I have done some optimizations for Linux Audio and USB audio. These do seem to have improved the sound quality through the dongle but they haven't solved this weird sound problem on incoming calls. If anyone's interested, my tweaks were; using the lowlatency kernel and adding 'snd-usb-audio nrpacks=1' to my /etc/modules. Has anyone experienced this sound? Thanks much! Peter Hartmann Hartmann Computer Consulting