Mobile device operating system vendor Symbian has signed up Taiwanese handset manufacturer BenQ, its first deal with one of Asia’s big contract manufacturers that its rival Microsoft has been targeting.

The deal marks a shift in strategic emphasis for London-based Symbian, which has now turned its attention to the Chinese and Taiwanese contract manufacturing sector after concluding licensing deals with all the major mobile phone manufacturers.

When Symbian beat Microsoft to those big-name phone makers, Microsoft turned its attention to mobile phone operators and contract manufacturers in Asia. If it could put the two together, companies such as Nokia and Motorola would be forced to switch to Microsoft’s Smartphone operating instead – or be marginalised.

That strategy now risks being upset by Symbian’s renewed vigour in courting the contract manufacturers. BenQ, owned by computer maker Acer, will license both Symbian’s multimedia operating system and its user interface.

Microsoft’s main mobile operating system licensee remains Taiwan’s HTC, which manufactures mobile phones for Orange, the mobile network operator owned by France Telecom. It also has Compal, which released its first Smartphone-based device in December.

However, Microsoft’s strategy may be damaged by the high-profile defection of handset designer Sendo, in which Chinese manufacturer CCT Telecom owns a major stake. Birmingham, England-based Sendo was to design Smartphone-based handsets that would be manufactured in China by CCT and sold to Europe and America’s big mobile phone operators.

But Sendo ripped up its licensing agreement with Microsoft in November 2002 and subsequently filed a law suit in Texas against Microsoft, claiming theft of trade secrets, unfair competition and fraud.

If Sendo were to win, the future of Microsoft’s operating system would be cloudy because of Sendo’s claim that Microsoft stole technology that made Smartphone work and passed it on to other contract manufacturers.