[Asterisk-Users] iax2 without iaxtel.com

[Asterisk]

Greetings everyone. Could anyone tell me how to setup an IAX call using
iaxcomm from a remote (PC) user without going throug iaxtel.com?
I would like users to register to my server directly instead of looking
up in iaxtel directory. Please provide an example of iax.conf commands
and extensions.conf. 
Your help would be greatly appreciated.
Thanks in advance.
Ricky