[Asterisk-Users] Remote dialtone

[Karlos]

Hi,

I have two asterisks connected via IAX2 trunk. The first * use dial 
prefix 2XX, the second one 3XX.
Calls routing works OK.
But I don't know how to get dialtone of remote asterisk pbx.
I'd like to get dialtone of asterisk #2 after dialing 3 and dialtone of 
asterisk #1 after dialing 2.

I know something about DISA but I'm not sure if it is a right way.
Can you give me advice?

Thanks.

Karlos.