[Asterisk-Dev] IAX2 protocol question

[Tim Robbins]

 From reading the Asterisk sources, it looks as if the FORMAT 
information element, when sent as part of an ACCEPT frame, lets the 
calling IAX endpoint know which formats are supported by both parties. 
However, libiax2 (and therefore the majority of IAX softphones) does not 
send a FORMAT IE as part of the ACCEPT. In this situation, what is the 
"right" way to determine which format voice frames should be sent in?

Thanks for any suggestions.

Tim