A bit of context:
In my Audi car, I have a MP3 USB/SDcard additional module that plugs into the CD changer plug of the OEM navigation unit and emulates the CD changer behaviour (6 CDs = 6 MP3 directories on the USB stick). This module has bluetooth capabilities too (A2DP and HFP/HSP profiles).
The behaviour is following:each time my Iphone 4G emits a sound alert over bluetooth, the music is cut, the alert is broadcasted and then, the music comes back normally. Such behaviour is very comfortable for speed cameras alerts as everything is done transparently and the alert is broadcasted in the car speakers, you cannot miss it.
Btw, I dunno which profile is used to achieve that. I suppose it's A2DP as the sound quality is great and similar to when I stream music from the iPhone:
1) reading mp3 from USB stick
2) pressing play button on the Iphone or a remote button on the module
3) the module switches automatically to A2DP streaming mode
4) the iPhone music is played into the speakers
==> only one press to achieve all of this
Now, what's the behaviour of the kenwood headunits having bluetooth ?
Particularly the KIV BT901 family (HFP/HSP, no A2DP) and KDC BT61U family (HFP/HSP, A2DP and more).
I'm pretty sure they use the same base for bluetooth than the past KDC X993.
Imagine my iPhone and the kenwood are already paired, and I'm listening FM radio or mp3 on USB stick. What would occur if my iPhone emits a sound alert ? Will the kenwood unit switch off the current source to broadcast the alert and hten go back to the original source ?
Or should I use a trick with auto-answering mode set to 0 ? (if the alert is emitted using HFP profile).
Btw, what is the headunit behavior if listening to the FM radio and pressing playback button on the iPhone (both are already paired of course), does the unit switch to Iphone/iPod source directly ?