I had the problem a few months back at http://www.geekzone.co.nz/forums.asp?ForumId=65&TopicId=24226 and I managed to fix it after a lot of work, wish I had documented how.... I've since installed a new trixbox instance on better hardware and can't find how to fix this. Call goes out on second line and about 10 seconds later gets torn down due to not getting the "OK" message.
The above was happening untill yesterday, however strangely after rebooting the device today, now when calling out, I get no voice, I hear ring, but when calling out of either of the trunks there is no sounds either way :/
Any help would be appreciated.