Can't dial any number

[Claudio_]

Hello.

I am newbie on Asterisk.
I added a Ericsson ipphone on Asterisk, but I can not dial any number.
I mean, I deal an internal ext. , the line opens and nothing more.
Incoming calls are OK.

Please, how can we solve this problem.
Thank you for your help.

[COpeter]

to be able to call you must add your extension to the extensions.conf too. other then that i dont know.