Sony MEX-BT3800U Bluetooth Car Stereo with Usb and Front Aux InputNever normally write reviews, but there seems to be lots of confusion over car stereos and iPhone 4 compatibility.
Just had this stereo installed, and it works perfectly with my iPhone 4 (firmware = iOS 4.01)
Here is a brief summary of functionality -
1) Hands free bluetooth audio - once paired (easy procedure, follow the manual!) the Sony MEX-BT3800U can stream any audio the iPhone 4 can play via bluetooth. This includes iPod app, Spotify, wunderRadio, and sat nav. By using the iPhone multitasking, it can stream sat nav commands over the top of a music or radio app: the music is faded down and back up to make the instructions audible.
2) Hands free bluetooth phone calls - no problems, as advertised.
3) Bluetooth controls via the stereo / car - due to Apple firmware limitations, you can currently only control the volume and play / pause functions via the stereo (or steering wheel controls if your car has them). Apple are shortly due to release version 4.1 of its firmware which supports the full AVRCP profile (i.e. you can skip tracks etc via an external device.) This firmware is due in September.
4) USB compatability. Many people have reported that the iPhone 4, or firmware iOS 4 does not play nice with car stereos. The Sony MEX-BT3800U doesn't have any problems - it works as advertised. As soon as the Apple data cable is connected, it usually takes control of the iPod app and the music begins to play. Again, you can switch to another audio app, e.g. Spotify or sat nav and this also works. If anyone is having problems, here are some solutions to solve audio problems with USB connections-
a) turn bluetooth off in the iPhone settings menu BEFORE plugging in the data cable. The iPhone 4 sometimes prioritises Bluetooth audio to the dock connector otherwise. This can stop audio playing.
b) turn off any audio programs that are in the multitasking bar BEFORE plugging in the data cable - the Sony MEX-BT3800U will then be free to open the last used program and the audio API controls will be freed by the phone.
c) If the iPhone 4 is connected but the stereo dash unit fails to locate any audio tracks , press and hold the'Mode' button on the left hand side of the dash unit for one second. This will kick the stereo into a special 'iPod' mode as opposed to simply USB audio. You will then be able to control tracks via the iPhone 4 in addition to the stereo interface.
d) some people have found doing a hard reboot of the iPhone while attached to the stereo works if it gets stuck. I didn't have to do this however.
5) The MEX-BT3800U will charge the iPhone 4 over USB. Just make sure that the data cable used is the one that came with the iPhone 4 (apparently the iPhone can tell...spooky)
Overall, this is a great radio! Hope this helps anyone who is stuck :-)