NTT Mobile Communications Network, Inc. (NTT DoCoMo), an NTT subsidiary that specializes in wireless communication services, announced the alliance the day after it announced a separate alliance with Sun Microsystems Inc. on Java technology.

"Collaboration with Sun is for cellular phones with the 'i-mode' services. As to Windows CE, we will collaborate to implement it as an operating system to not only cellular phones but also PDAs and other portable communicators," said an NTT Docomo spokesman.

NTT Docomo's i-mode service, which is designed to enable Internet access directly from a digital cellular phone, has attracted 24 million subscribers since it became available in February.

"Currently the i-mode phone has a fixed browser in ROM. If clients want to offer their special security, for example, the browser does not support such an individual request. So we will provide a common platform with Java, on which each client can develop its own service," said Kei-ichi Enoki, director of NTT Docomo's Gateway Business department. Electronic commerce applications are the most likely ones to be developed on the Java platform, he said.

Microsoft and NTT Docomo will work together to improve cellular phone call quality, and to support high-speed PHS data communications on Windows CE. PHS is Japan's personal phone system.

The two companies will also co-develop data center services that will enable users to access from their mobile terminals individual pieces of data stored in the data center, such as e-mail, individual schedule tables and address books. The agreement also includes the possibility of joint development of portable communicators other than cellular phones that would work with the data centers and use software based on Windows CE and a micro-browser now under development at Microsoft.

The companies haven't disclosed any marketing plans for the collaboration's resultant products.