SIP Videoconferencing SIP client Instructions Above you see the SIP client integrated into X-Smiles. You can contact other people by selecting them from the address book or by using URI such as 'sip:username@hostname'. Of course, the other side also has to have the SIP client online. If you have enabled registration, X-Smiles registers you at startup for 24 hours. Currently there is no feedback about the success of registration, please see the log for feedback.