Originally Posted by EdwardL

It plugs into both the USB and AUX slots, which are in the centre console/armrest, hence the "Y". In case you didn't already know, you only get these slots if your car has the 6FL usb/audio interface option.

If in addition to 6FL you also have the 6NF extended music connectivity/smart phone integration option, then instead of the "Y" cable, you could get the iPhone snap-in adapter, which also goes in the armrest - the base plate takes up half the space so you can't miss it. While the iPhone is docked into this cradle it is charging, connected to car antenna for better reception, and enables iPhone music play.