The A/V connection seems to be a valid reason, but...
Ever used a Ford with MS Sync? I rented a Focus with this on vacation last summer, and it works quite well - a surprisingly innovative and compatibile product for Microsoft.
It hooks up to your iPod/iPhone with the standard USB cable, and can play audio, so it has to stream it over the USB connection somehow, or it rewires the port, which seems unlikely to me, as you'd run out of pins (stereo audio, power, control, ground = 5 pins minimum).
I really wonder how this is accomplished, as it can play back protected AAC music, which must be decoded on the phone, so it isn't just using the device as mass storage...
A radio transmitter for iDevices will use the audio out lines on the dock connector, whereas the USB cable purely breaks out data, as far as I'm aware, so they must be doing something different.
iPod can stream protected audio content over USB. You just need an auth chip approved by Apple to be able to do that. Most of the cheap devices just use analog audio out and use "Apple Accessory Protocol" (which can be sent over either serial port or USB) to control it.
Ever used a Ford with MS Sync? I rented a Focus with this on vacation last summer, and it works quite well - a surprisingly innovative and compatibile product for Microsoft.
It hooks up to your iPod/iPhone with the standard USB cable, and can play audio, so it has to stream it over the USB connection somehow, or it rewires the port, which seems unlikely to me, as you'd run out of pins (stereo audio, power, control, ground = 5 pins minimum).
I really wonder how this is accomplished, as it can play back protected AAC music, which must be decoded on the phone, so it isn't just using the device as mass storage...