Windows Phone 7: What's behind chassis doors 1, 2 and 3?

Windows Phone 7: What's behind chassis doors 1, 2 and 3?

Summary: It sounds like there are three different chassis specs to which mobile developers interested in building Windows Phone 7 Series devices will be adhering. There aren't many public details on what these specs include, but thanks to a couple of Microsoft podcasters, here's a little more information.


Microsoft execs have been explaining and re-explaining what the company's decision to tighten its mobile requirements will mean for both its phone makers and customers when the Windows Phone 7 Series phones start shipping late this year. But one set of details about which they've offered scant public information is specs.

Thanks to a reader tip, however, I listened to the "Frankly Speaking" podcast (dated February 20).  About 3.45 minutes in, the Microsoft Australia Developer Evangelist hosts (Michael Kordahi and Andrew Coates) start talking about Microsoft's decision to cut back the unwieldy number of supported Windows Phone chassis to three with Windows Phone 7.

Chassis 1 is for PC makers developing "big touch screen" phones, the hosts said. These will be touch-only devices, with 1 GHz processor (hello, Snapdragon!) and a dedicated graphics processor, the Frankly Speaking guys said. These are the phones that will be out first at launch this holiday season.

Chassis 2-compliant phones will support real sliding keyboards plus touch, the podcasters claimed. They said these would be more Palm-Treo-like. There also will be Chassis 3 phones, about which the pair didn't have any details. One of the hosts (I couldn't tell which) said he expected Chassis 3 phones might be candy bar phones. The pair didn't say when Chassis 2 and 3 phones might ship.

It's been rumored for over a year that Microsoft would be locking down its phone ecosystem so that fewer partners were required to adhere to more rigorous specifications. In fact, all those rumors about Microsoft making its own Windows Mobile 7 phone were more likely than not, actually rumors about the evolving set of chassis specs that Microsoft was creating for its Windows Phone partners.

Last year, I posted a copy of a spec list for Windows Mobile 7 Chassis 1. At the time, I was led to believe this was the chassis spec for the forthcoming Microsoft Pink phones, but now I don't think that's the case. (And I'm still unclear what the operating system in those Pink phones will be.) These days, I'm wondering how close that WM7 Chassis 1 spec is to the current spec? At that time, I also had heard talk of Windows Mobile 7 Chassis 2 and 3, but never was able to get more information on those specs.

I've asked Microsoft for more information about its Windows Phone 7 chassis specs, but I'm not holding my breath.

(Update on February 24: The official (non)statement, via a spokesman: "Microsoft does not have any further comments on the information our Australian subsidiary shared recently.  MIX is where we will share our next update on our mobile platform.")

In other Windows Phone 7 news, it looks like Microsoft might be sharing more details about its developer tools and strategy for the platform slightly ahead of the Mix 10 conference. MobileTechWorld has information about some of the mobile-dev-centric sessions Microsoft is planning for the Game Developers Conference, which is slated for the week before Mix 10. The write-ups for these sessions say they will cover "Windows Phone" gaming development (not Windows Phone 7 gaming development), but I'm betting the latter topic will be part of what's discussed. (One of my sources told me recently that games developed using the XNA gaming framework will be targeting Windows Phone OS 7.1 devices, not the first-generation 7.0 ones. Guess we'll find out if that's true soon....)

As I noted last week, it sounds as though Microsoft is planning to make Silverlight and XNA its primary Windows Phone 7 development platforms, introducing new design and development tools to support programmers interested in writing applications for its Windows Phone 7 and Zune HD platforms.

There's one more thing: After listening to the aforementioned "Frankly Speaking" podcast, it finally sunk in that the Windows Phone 7 user interface, while borrowing heavily from the Zune HD UI, actually takes its earliest cues from Media Center. The hosts noted that the "Metro" user interface on the new phones came out of the work Microsoft pioneered with Media Center.

Topics: Telcos, Microsoft, Mobility, Operating Systems, Software, Windows


Mary Jo has covered the tech industry for 30 years for a variety of publications and Web sites, and is a frequent guest on radio, TV and podcasts, speaking about all things Microsoft-related. She is the author of Microsoft 2.0: How Microsoft plans to stay relevant in the post-Gates era (John Wiley & Sons, 2008).

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  • It's at least a year ...

    ... out. So you can turn down the hype, at least for now.

  • Not in this economy

    In these economic times, we need all the lead time we can get to pay for it upfront, no contract, so we can hack it, whack it, and sell it for a profit!

    Hack it! Whack it! And sell it for a profit!
    Hack it! Whach it! And sell it for a profit!
  • I feel its 7.0 only

    otherwise, they would not have been adding their sessions at Game developer's
  • Rugged phones move to Android

    There have already been some industrial-style and rugged handsets moving to the Android platform. This will increase, as the old Windows Mobile Classic is at end-of-life, and handset makers look for an OS adaptable to more form factors.

    Because Microsoft will lose the rugged device sector, it gives further weight to Android ultimately becoming the business phone platform of choice. It's not there yet, but it is growing exponentially in that sector. You can see the trend. No other major OS allows itself to be used in such a wide variety of handset form factors as Android.
  • RE: Windows Phone 7: What's behind chassis doors 1, 2 and 3?

    I keep wondering if Metro, referring to an interface in MCE built in WPF and an interface on WinPhone probably built in Silverlight (which was originally called WPF/e for everywhere) is anything to do with Metro, a device independent rendering system built on WPF that we know better as XPS? It's my own weird little conspiracy theory and Joe Belfiore's Media Center background probably makes it likely that it's just a codename collision. Microsoft told me that Metro refers back to transportation signs; they're very clear and they have just the information you need...
  • Good stuff Mary

    Mary, just wanted to say thanks for your consistent good and level-headed reporting throughout the years. Keep up the good work, and I'd like to hear you on Windows Weekly more often!
  • Windows Embedded CE for mobile phone

    "...It?s been rumored for over a year that Microsoft would be locking down its phone ecosystem so that fewer partners were required to adhere to more rigorous specifications..."

    For Phone makers who like to introduce their own UI or other innovative specification.

    I wonder can those manufacturer use Windows Embedded CE for those design instead of the Windows Phone 7 series OS.

    If that is possible, MS will have the best of both world. (provide that they give some marketing to CE as an alternative phone OS)

    Thanks for reading.
    • Yes, they can use CE if they like

      WinCE will continue to develop independently of WinPhone because WinCE is used in many other device form factors from ATM's and retail checkout systems to embedded data loggers etc.