First Windows Phone 7 'Mango' handsets rumored to challenge iPhone 5 in Sept.

Sources told Taiwanese industry publication DigiTimes that handset vendors plan to launch their new Mango devices in September, even as Apple is expected to release the iPhone 5 during the same timeframe. For its part, the Redmond, Wash., software giant announced earlier this week that it had sent Mango to handset and carrier partners on schedule for a fall release.

Acer, ZTE And Fujitsu Toshiba have also recently shown off Mango phones that are expected to arrive this fall. For instance, the report notes that Fujitsu Toshiba is working with Japanese carrier KDDI to bring to market the IS12T, which features a "Qualcomm MSM 8655 processor, 3.7-inch touch screen and 13.2-megapixel camera."

Insiders noted that HTC is expected to release "a number of Mango phones, powered by Qualcomm 1.5GHz single-core CPUs with display sizes ranging from 3.8- to 4.7-inch."

Meanwhile, Nokia, arguably the vendor most committed to Windows Phone 7, will reportedly unveil its first batch of Mango devices at Nokia World 2011 in October. According to the report, sources implied that the Finnish handset maker's strategy may be to release its first Windows Phone 7 handsets "at a time when fellow vendors have already heated up the market for Mango phones."

Nokia CEO Stephen Elop said last month that he has "increased confidence" that the company will launch its first Windows-based device later this year and begin to ship in volume next year. 2011 and 2012 are to be "transition years" for the company, which for years reigned the global smartphone market until Apple's iPhone displaced it last quarter.

Microsoft first showed off Mango in May, touting "more than 500 new features."

Notable additions to Windows Phone 7 Mango include Conversation View for emails and threaded conversations that bring together text, instant message and Facebook chat all into one conversation. The update will also introduce app multitasking and Internet Explorer 9, with support for new HTML 5 web sites.

Though recent data from Nielsen shows Microsoft has held onto just a 9 percent share of the U.S. smartphone operating system market, the Windows maker is betting that its stable of partners will provide the momentum needed to challenge the iPhone and Android when Mango arrives this fall.

Several recent rumors have pegged the iPhone 5 for a September launch. On Wednesday, the China Times claimed that suppliers have said Apple will release a next-generation iPhone during the second week of September. Also, AT&T is reportedly preparing for a mid-Sept. launch.

The new handset is said to be thinner and lighter, with the A5 processor and an 8-megapixel camera. Recently discovered photos also suggest that Apple is working on a cheaper, lighter and faster revision of the iPhone 4 that could become the company's entry-level model alongside the fifth-generation iPhone.