When Microsoft prepped cell phone manufacturers about Windows Phone 7, they were crystal clear in defining the minimum hardware specifications each phone would have to support the mobile software--a touch screen, 1 GHz processor and 5.0 megapixel camera, for instance. Android's rapid development, on the other hand, makes minimum hardware specs murkier. They're documented but less understood than the distinctions between the software versions themselves.

As a result, we've combed through page upon thrilling page of compatibility documents to bring you the minimum hardware requirements of your Android phone and breaking down what that means.

Before we begin, note that Google has not posted documentation for Android 1.0, 1.5, 2.0, or 2.0.1' the company cites technical reasons. Also note that we omit comparing Apple's iPhone, BlackBerry smartphones, and Palm phones because they're closed manufacturing systems.

'Must' versus 'should' While this list reflects the minimum requirements that Google imposes on manufacturers, it isn't the full story. The Android team makes many hearty recommendations in legalese that "may" or "should" be used when building Android-compatible phones. For instance, a Micro-USB port isn't mandatory, but it is encouraged, as are hardware buttons and a dedicated search key. The base storage requirements also appear low, but Google recommends 128MB RAM and at least 1GB of on-device user storage for things like the address book and photos.

As the chart shows, Google's requirements have been mostly unchanged since Android 1.6, with the exception of making GPS, Bluetooth, the accelerometer, and the compass mandatory.

Interestingly, there is one notable alteration that pops out. Android 1.6 specifically calls for Wi-Fi. (And we quote, "Device implementations must support 802.11b and 802.11g, and MAY support 802.11a.") Android 2.2 relaxes this to allow for lower-end phones to use data without using Wi-Fi. 1.6 also demanded volume controls. Not so in Android 2.0 documentation and above.

The Android-powered T-Mobile Comet will sell for $10 with a two-year contract.

Decoding the specs Looser hardware requirements don't necessarily mean poorer-quality devices, as high-end smartphones like the HTC Evo 4G and the new My Touch 4G attest. However, they do lower the barrier to making smartphones, and the combination of a mid-tier hardware like a 3.2 megapixel camera and 600 MHz processor mean that phones can be built--and sold--for less.

Take, for example, the $30 LG Optimus T and the $10 T-Mobile Comet. Such low prices (with a new two-year contract) will surely attract budget-conscious users who might otherwise not seek out a smartphone. We're going to start seeing many more feature-phone owners switch to some of these more entry-level Android devices, not all of them very good.

Despite the occasionally poor or puzzling choice in hardware design, many of these lower-end Android phones do come with Android 2.1 and Android 2.2, and they offer consistently good software perks for users on any device--Google Maps with Navigation and the integrated Google Account address book are some favorites.

Stricter minimum requirements, like those found in Windows Phone 7 devices, do ensure a basic level of quality. At this point in its product life cycle, Windows Phones offer among the fastest processing speeds on the market. However, Microsoft's basic smartphone requirements pose no guarantee that manufacturers will produce a compelling product. We certainly found the HTC Surround--with its slide-out Dolby Mobile speakers--less compelling than the Samsung Focus and the Dell Venue Pro.

Comparing Android and Windows Phone's minimum specs does tell us at least one thing, though--that we'll continue seeing Android phones in a broader range of shapes, sizes, and levels of power than you will a Windows phone. At least for now.