Right, as promised I did some experimenting this morning... And have the answers
Firstly, when someone calls you there are three options :
1. Use the button on the steering wheel if you have it
2. Swipe to answer
3. Choose whether to answer the call or hang up
Using the button is easiest - it routes the call through the car automatically so you can hear the call, and the phone throws up the option to choose the audio source on the screen. Handy if you want to get out the car whilst continuing the call.
Swiping to answer routes the call through the phone, but you are then presented with this screen :
Now, we're driving here so not paying total attention to the phone (one assumes...), but as you can see there is an option to choose the source at the top right. Touch this, then select the car from the list. Not ideal as you need to spend quite a lot of time looking at the phone.
The last option is not really practical when driving - in the photo below you see a wee phone to the right of the swipe bar. If you swipe this button up, like using the camera when the screen is locked, you get options to answer the call or not. It is quite hard to swipe this in a cradle when stationary without looking at it while you do it, so I will not be trying it while driving. If you answer the call you then need to select the audio source as above.
So, using the button works best - I don't think that you can have BT integration without the controls, but if you can then just swipe and select source. Not a great option though, as proven by the fact that none of us saw the button to select the source when we were using it whilst driving.
Sorted my email synching between devices as well this morning after a little googling - maybe I should go fit my Intravee while I am on a Tech Fix Roll
