technical issue about audio transfert from AG TO HF device

Hi,



I'm doing a little bluetooth application for my traineeship and I would like
some clarification about audio transfert from audio get way to Hand free
device (HS or Car kit).

If a service level connection exist between AG and HF and an incoming call
is ringing on the AG, when the call is answered from the AG, what is the HF
behaviour when I push the HF button to start the audio transfert?

Is the HF establish the SCO link or sends an Answer event or an event to
start a voice recognition procedure?

I have the feeling that all the device have not the same behaviour...



Thanks for your help



Best regards



Bigbang