Can anybody explain me this, please. How is the rtp stream with video? Which ports are usually used for that? Following thoughts I have how it could be: 1. video and audio are two indipendent different rtp streams 2. audio starts with the lower free udp numbers, video with the higher ones. Only that could give me an explanation, why audio is ok in our test, but no video, and only if we want to call to a NAT, but worked from it. Where can I get more info? bye Ronald