Asterisk manager API?

If I use:

Action: Originate
Channel: SIP/103
Context: default
Exten: 102
Priority: 1

it will call phone 102 from phone 103 on my internal SIP phones network connected to Trixbox2.2.

How can I call some other number…like my cell phone…over IAX trunk???
I have IAX2 and SIP trunk on asterisk and phones are working fine. Now I’m making some kind of dialer and I need to know how to make outbound call…:frowning: