Four handset makers and two operators have joined forces to develop a new Linux software platform for mobile devices - and formed the third mobile Linux group in a year.

The companies, including Motorola, Vodafone, NTT DoCoMo, Samsung, NEC and Panasonic, plan to develop an API (application programming interface) specification, architecture and source reference.

The group will collaborate on a mobile Linux development ecosystem, with the founders creating a reference implementation of the mobile operating platform, and other companies invited to join, including phone makers, operators, chip manufacturers and software vendors.

The foundation also hopes to offer a test suite so that developers can demonstrate that their products conform to the specification.

Linux is already a popular operating system for phones in China and is just gaining momentum in Europe. Operators and phone makers say that using Linux can help them reduce the cost of handsets.

This will be the third mobile Linux group to launch within a year, joining the Linux Phone Standards (LiPS) Forum and the Mobile Linux Initiative (MLI). Like the new foundation launched on Friday, the LiPS Forum aims to focus on the creation of APIs to enable interoperability of applications across Linux handsets.

PalmSource, France Telecom and Orange are among the leaders of LiPS. The MLI, with members that include Motorola and PalmSource, is working on unifying developments around the mobile Linux kernel.