3. Making a call

3.1. Basic principles

Linphone uses the Session Initiation Protocol to establish the connection with a remote host. In this protocol each caller or callee is identified by a SIP url: sip:user_name@host_name. A sip url is very closed in syntax to an email address, excepted the sip: prefix.

User_name is like a login name on an Unix machine, and host_name is the name or the IP address of the machine the user can be joined.

Note that Sip is a new telecommunication protocol designed to be simple, and it is not compatible with H323 at all.

3.2. When IP address are not static

For that purpose, you can register to a sip proxy. There exists several sip proxies on the net, for example see http://iptel.org, it's free. You'll just need to get an account on the proxy and then tell to linphone to use it.

3.3. test trial: you have no friends to call at the moment (because it is too late for example), but would like to know if linphone really works