[Asterisk-Users] Conference Server

[pesb]

Hi there,
             I need to implement a SIP Conference Server. I've saw that 
asterisk has an application called meetme. But, it says that "A ZAPTEL 
INTERFACE MUST BE INSTALLED FOR CONFERENCING FUNCTIONALITY".
Is there any other way to implement a conference server without the need of 
having a ZAPTEL Interface?
I need my conference server to work only with my SIP Phones.

thanks in advance,
                              Pablo Salinas