A pair of Taiwanese companies have signed a technology agreement to develop 3G and 3.5G smartphones around the Windows Mobile OS, adding to the growing pool of companies developing mobile phones around the Microsoft software.

E-ten Information Systems and Arima Communications will combine their technical expertise to deliver at least four new Windows Mobile-based smartphones to global markets by the end of this year, they said in statements to the Taiwan Stock Exchange.

Arima has experience with handset technology for Ericsson mobile phones and related chipsets, in addition to the Microsoft Windows Mobile OS and networking chips from Marvell Technology, while E-ten has developed several handsets around Microsoft Windows Mobile using communications processors from Samsung Electronics, the companies said. The two companies plan to use their combined expertise to develop high end 3G smartphones that allow uploads and downloads using HSDPA (High-Speed Downlink Packet Access) or Wi-Fi technology, as well as GPS (Global Positioning System) for maps, and Bluetooth technology for device to device links.

The new cooperation is a further sign the Microsoft Windows Mobile OS continues to catch fire, even amid stiff competition from popular handsets such as Apple's iPhone and Research In Motion's BlackBerry devices, in addition to OSes such as Symbian and Embedded Linux. Taiwan companies have been helpful partners for Microsoft in the handset arena. High Tech Computer Corp. (HTC), the world's largest maker of mobile phones using the Microsoft Windows Mobile OS, is also a Taiwanese company.

E-Ten already has a smartphone out, the Glofiish X500, which uses the latest version of the Microsoft OS, Windows Mobile 6. The company is a long-time developer of GPS devices.