[Asterisk-Dev] IAX busy indication but not invalidating the call

[Lee Howard]

What is the proper way for an IAX client (softphone) to indicate 
"congestion" and/or "busy" to the peer such that the peer will proceed 
along the dialplan rather than aborting the call altogether?

I've tried using REJECT after receiving the peer's CONNECT; however, 
that results in the call being aborted by the peer rather than 
continuing in the dialplan.

Thanks,

Lee.