asterisk users - Jul 2005 - Strange softphone issue - audio open before answer

Hi All...

I'm not sure if this is a bug or a feature.  When I use a soft phone such 
as iaxcomm and firefly, I find that when the extension is rung from any 
channel (zap, IAX, SIP) that while the phone is ringing, before it is 
answered, audio is passed between the caller and called phone.

This even happens when people call from the outside world.  Is there a way 
to stop this?

Thanks very much...