AT&T will launch three new Windows Phone 7.5 "Mango" phones this fall while updating its existing four Windows Phone 7 smartphones with the new mobile operating sysem, the carrier said Monday.

The three new phones, debuting at unannounced dates and prices, are the HTC Titan and the Samsung Focus S and Samsung Focus Flash. All three will run on AT&T's 4G HSPA network, offering faster speeds.

The existing Windows Phone 7 devices that will get the Mango update this fall are the HTC HD7S, the HTC Surround, the LG quantum and the Samsung Focus. AT&T did not specify when the updates would be available.

AT&T called itself the "clear leader in Windows Phones" even though the platform has only attracted a fraction of the global smartphone market thus far. Jeff Bradley, senior vice president of devices for AT&T Mobility, said AT&T has sold more Windows Phones than any other other carrier or retailer. AT&T officials appeared with Microsoft CEO Steve Ballmer when Windows Phone 7 devices were first launched in New York last fall.

The HTC Titan will have a 4.7-in. touchscreen and will run a 1.5 GHz processor, making it one of the largest and most powerful smartphones on the market and AT&T's largest smartphone screen. It will also have an 8-megapixel camera in addition to a front-facing one. Microsoft officials said AT&T will get an exclusive "unique" version of the Titan, which was unveiled last week as a global phone. "We'll have to keep you in suspense for a while longer on what it looks like and final specs," Microsoft blogger Brian Seitz said.

An AT&T spokeswoman said no images of the three new Mango phones are available officially.

HTC announced on Sept. 1 it would have the global version of Titan , and also an HTC Radar phone, available in October in Europe and Asia.

The Samsung Focus S has a 4.3-in. Super Amoled Plus display for clarity and a 1.4 GHz processor. It includes a front-facing 1.3- megapixel camera and a rear-facing 8-megapixel camera and is a slim 8.55 millimeters (.33 inches) thick.

The Samsung Focus Flash is smaller, with a 3.7-in. Super Amoled screen, but a 1.4 GHz process and two cameras, with the rear-facing one at 5-megapixels. (No rating was provided on the front facing one.) AT&T and Samsung called the Flash a "value" device, which usually means it will be priced well below the going price for today's hottest smartphones that ran from $150 to $200 with a two-year contract.

Microsoft officials have declared there are 500 improvements in Mango over the original Windows Phone 7 , including the Internet Explorer 9 browser and support for HTML 5.

Matt Hamblen covers mobile and wireless, smartphones and other handhelds, and wireless networking for Computerworld. Follow Matt on Twitter at @matthamblen or subscribe to Matt's RSS feed . His e-mail address is [email protected] .

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