I modified the pjsua and try to make a call. And I found that the invite message start line is wrong. It shows: INVITE sip:192.168.2.54 SIP/2.0 but, the right one should be INVITE sip:2323 at 192.168.2.54 SIP/2.0 In the content, it is able to show the 2323 at 192.168.2.54. So, I believed I did pass the right parameter to the pjsua_call_make_call I use the 0.9. My question is anyone has similar problem ? Where can I find the method that form that line ? And which method to create the INVITE message ? Thanks for your help