Car Head Unit Compatibility with Windows Phone 7.5 Mango

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I recently had a desperate need to upgrade the audio system in my car, and wanted a good Mango-compatible system. I learnt a lot about Bluetooth and what to look for to get a great in-car experience, which I am sharing here. Please note these are my personal findings and opinions, none of this should be taken as a Microsoft-approved endorsement of anything.

Earlier in the year I picked up a 2006 Cayenne and for audio and navigation it came with PCM (Porsche Communication Management System). This is an over-priced, deeply underperforming piece of equipment. I shall save my large list of rants about it for another day, suffice to say it was a $4k or so option when new and offered no Bluetooth and no auxiliary audio inputs, to name but two critical missing features. This steaming pile of technology was fitted to Porsches from 2004 to 2009 and I can only hope that whoever was responsible for it is no longer with the company (or Harman/Becker who were the offending OEM). I suffered with it for many months, using a Zune RF car kit as the only way to get music into it, and by breaking the law using my phone directly on occasion. Finally with the release of Mango I knew that the expanded Bluetooth features of the phone should combine with a good head unit to solve all of my audio woes, and more, so I went shopping.

It became obvious very quickly that Apple totally owns the in-car audio experience right now: every head unit has as a built-in or optional feature of iPhone/iPod support. The power of that big proprietary connecter is huge, and that combined with the massive worldwide presence of the devices has resulted in excellent support.  How can a Mango phone possibly complete, with a lowly micro-usb jack and a tiny percentage of Apple’s market share? Without any wires, that is how, via the Bluetooth standard, as you will see.

Andy's Bluetooth Tests

Here are the Bluetooth tests that I performed and that I recommend you perform in choosing your next head unit (or new vehicle for that matter) if these things are similarly important to you:

  • First off pair your phone with the head unit under test. Get someone to call you, and verify the audio is routed over the speakers, and you can reply. This I call the Voice Test, and requires the most basic BT support from a head unit.
  • Next play the radio on the unit, and get someone who is in your Contact list to send you a text message. This should cause the radio to mute, and then the phone should announce via the car speaker something like “Message from Chris”. You can reply “Read it” and the message is read. You can also reply to text messages by speaking. This I call the Text Test, and for me is the single most important BT test, and one of my most favorite Mango features.
  • I remain a Zune fan (go here for the installation of same into my Boxster) but of course I can fit a bunch of tunes on my phone too. At minimum I needed a head unit with an analog audio input (so I could connect via the phone’s headphone jack), but a stretch goal for this plan was to play music from my phone wirelessly, over Bluetooth. This I call the Music Test.
  • When music is being streamed from your phone for the Music Test, it is obviously useful to be able to Pause, Next Track etc, in my case from the steering wheel controls. I call this the Control Test.
  • When you use an Apple device and cable it to one of these head units you are able to see what is being played (the artist name, track etc). This is possible with Bluetooth too, and I call this the Metadata Test.

Now to get a bit technical: each feature used in my Tests require one or more Bluetooth profiles, and different head units support different profiles (and different versions of those profiles). I do not pretend to be an expert in this, but to handle my tests above a head unit must support the following protocols:

  • Voice Test: HFP (Hands Free Profile)
  • Text Test: Unknown profile
  • Music Test: A2DP (Advanced Audio Distribution Profile)
  • Control Test: AVRCP 1.3 (Audio/Video Remote Control Profile)
  • Metadata Test: AVRCP 1.3

Note that there are other Bluetooth features that I don’t care about so did not test, such as phone book download (which uses the OPP Profile). Also missing is making a phone call, I very seldom do that from the car, but if that is important to you then I urge you to test it before you buy.

Some things can be immediately determined from a spec sheet, for example if the unit does not support A2DP then obviously it cannot pass the Music Test  and the Control and Metadata tests are irrelevant. The hardest one to determine is the Text Test: it isn’t clear which profile(s) it requires and it is the hardest test to pass (as you’ll see in my results later). Reading the specification sheets for a given head unit will tell you little about how well it will work with a Mango phone, you have to either try it yourself, or find someone who has already tried it. A list of head units that failed my tests can be found later, but to skip to the chase I highly recommend three JVC units.

Decision Time: JVC

So after trying out several options, I ended up with the JVC KW-NT50HDT which is a double-DIN touch screen LCD screen system with navigation. The KW-NT30HDT is probably a fiscally more sensible choice: the only difference is lifetime traffic data (which it gets from the HD radio data stream), and so far at least in the Seattle area this has not proved to be as useful as the DOT bitmap which has earned a shortcut on the home screen of my phone. This was connected to the existing amplifier and speaker system, as well as the steering wheel controls, and this is no mean feat. One of the many annoying features of the PCM system is that it is entirely digital using fiber optics to communicate between devices: this makes it overly difficult to get any kind of analog signal into or out of the system. Fortunately it is not impossible, if you go to an installer who knows what they are doing. It’s not cheap though.

I must say I am very happy with the JVC+Mango experience. First of course I get my favorite music and playlists onto my phone via the desktop Zone software, then start playing something on the phone and pause it. After I start the car it takes a few seconds for the Bluetooth to pair, then I can select BT Audio then Play, and that is it: wireless high quality music. The JVC displays all of the metadata (except the album art which is a limitation of AVRCP) and I can use my steering wheel buttons to navigate tracks. It even displays the state of my phone’s battery, which is handy as streaming audio is going to put some additional load on it for sure. When I turn the ignition off the phone automatically pauses my music, until I return the next day when it will resume where it left off. Just like the Zune in my Boxster, but wirelessly. Bliss:

There are other features of the JVC not directly related to Mango that I also appreciate, such as a USB port on the front which can charge your phone or take a memory stick full of music, and it shows all metadata including album art in this case. It also has a rear AV input which I use for my Zune, an input for backup camera that I had installed at the same time, and a very nice navigation system from Navteq. All of this is fast and easy to use, i.e. it bears no similarity to the PCM system it replaced: I had to get the instructions out just to use the radio on the PCM.

Life is not entirely perfect in Mango-land for Bluetooth though and there remain a few gaps. For example while the built-in media player works very well over Bluetooth, third-party applications that use a BackgroundAudioAgent do not work so smoothly. (You can tell which apps these are as you can control Play/Pause/Next/Prev with the lock screen down using the Universal Volume Control or UVC). The UVC is not really connected to Bluetooth, so while you can sometimes Pause/Play those apps from the head unit (and steering wheel) you cannot change tracks. You also get no metadata at all sent to the head unit. For tethered Apple hardware the JVC supports iheartradio and many other units support Pandora by building it into the head unit itself, which is clearly not a sustainable model even for Apple, so Microsoft has an opportunity to improve the support for arbitrary 3rd party applications over Bluetooth here:

Although I installed my Zune myself in the Boxster, I was not about to attempt to install this lot into the Cayenne, so I went to Benchmark Motoring for it. I highly recommend them, speak to Justin if you pay them a visit. For reference all my testing was done on a Dell Venue Pro, which had a deservedly poor Bluetooth reputation before the BSP update that Dell shipped around the NoDo timeframe. Since that update mine has been rock solid.

A final note about Zune: sadly SoundGate products are no more, so connecting a Zune to a head unit via a quality connection is even more of a challenge. Fortunately I did score one of the last ZNCBLPAK kits on the planet and had it installed along with everything else. Although my Zune for music is more or less obsolete now in the Cayenne, it can do video through the JVC which might keep the kids occupied for a while on occasion.

Known Andy-Compatible Units

  • JVC KW-NT50HDT
  • JVC KW-NT30HD
  • JVC KD-A925BT


Known Andy-Incompatible Units

  • Alpine INA-W900BT: Voice Test passed. Text Test failed, no A2DP support so all other tests N/A
  • Kenwood DNX9980HD: Voice Test passed. Text Test failed, except while running the Music Test! (which passed)
  • Kenwood KIV-BT900: Voice Test passed, Text Test failed. Can directly control a wired Zune though!
  • Dension Gateway 500: Every test fails (even Voice!) except Music.

A Comment about Comments

Please don’t post comments asking me if device XYZ is compatible: everything I know about compatibility is listed here. On the other hand if you have tried Mango on some other hardware and can share your test results in a comment that would be much appreciated.