IAX2 trunk problem

what 's the exact mean of iax2 trunk?
if i want to connect two asterisk server,what i should do?
the following is my request:
iax softphone A registered in asterisk server SA,
there is a asterisk server SB,and in SB ,there is a context and extension
such as 1000.how i use trunk or something else to dial 1000 in asterisk Server SB using softphone A which registered in SA.
thank you !

I think this is what you are looking for.

i have a try as the documen describe but fail.
btw, my aah version is 1.3. maybe i think i should do something in extension.conf but i donot know what to do or how to do.
because my softphone users are connected with the mycontext.
can you give me much more detail about it?
thanks you in advance.

First off i’m not sure if your version has any effect on this. But I did forget to mention that in the directions it says put a 7 for outbound prefix but you should leave it blank. When you are done with the trunk create an outbound routing and enter this into the dial pattern 7|XXX then for the trunk sequence select the trunk you just created. Thats it you should be able to call the second server now.