Hi, I'm using the last version in trunk of pjsip. When I use pjsua I receive this assertion : Assertion failed: (!"Calling pjlib from unknown/external thread. You must " "register external threads with pj_thread_register() " "before calling any pjlib functions."), function pj_thread_this, file ../src/pj/os_core_unix.c, line 620. For information line 620: pj_thread_this() function I don't think this is a problem of pj_thread_register, but perhaps some pthread functions don't work correctly on Ipod/iphone. I think that the topic has already been discussed on the mailing list but I don't find when :-( What do you think ? Samuel