[asterisk-dev] stupid error in configuration

[Wojciech Puchar]

i can call anyone in my PBX, as well as others can call me and everything 
is fine. Except i don't hear "booo   booo" when called party hears 
ringing, but it's "booooooo" just like before choosing number.

I have two PBX. Phones are SIP IP phones - different, but all have same 
problem. They are connected over IAX2 trunk.

Please give me a hint what to look at to find out a problem as i have 
completely no idea.