What happens if you're using some normal earphones that happen to fit (ie. without a mic), and you get a call in - doe the headphones still fade out, and is the caller routed through your earphones, so you can then just hold the iPhone up to your ear and speak into the phone? Or do the headphones cut off (if you're listening to the iPod for instance) and then you just have to take them out and use the phone as normal?