The companies plan to form an industry initiative by the end of the year and will invite other participants from the semiconductor and mobile phone sectors. The companies will develop standardized API specifications and architecture for mobile phones, as well as support for source code-based reference implementations and tools to check the compliance of application programs with the API.

Motorola and Samsung are the second and third vendors, respectively, in the global mobile phone market following Nokia, according to Gartner Dataquest. Panasonic is the tenth-ranked vendor But in Japan, Panasonic and NEC rank second and third, respectively, behind Sharp, according to Tokyo based MM Research Institute, Ltd.

Some industry observers believe the Linux platform movement would directly against Symbian, a specialized mobile operating system.

This Linux platform announcement however, does not suggest Docomo is leaning strongly to Linux, said a Docomo spokesman. The largest carrier in Japan with about 56 percent share or 51.4 million subscribers, Docomo has been developing handsets based on both Symbian and Linux. Panasonic and NEC are working with Docomo for Linux-based handset development.

Some mobile phone vendors have started using Linux for their products, but open specifications tend to lead to format fragmentation resulting in incompatibility even on the same Linux environment, said the Docomo spokesman. These companies' joint efforts would boost Linux based mobile phone development, he added.