The prototype device, which will be demonstrated at the CeBIT technology show in Germany this week, enables the R520 to play WMA files, as well as streaming Internet radio, Microsoft said in a statement.
Handsets that can play WMA files are already available in Japan. The companies said they see a bright future for such devices as higher speed transmission technologies such as GPRS (General Packet Radio Service) and 3G (third-generation) mobile networks become available.
Microsoft launched beta versions of Windows Media Audio 8, as well as Windows Media Video 8, at the Streaming Media West 2000 conference in December. Files encoded using the beta release can play audio files that are near CD quality but are only one-third the size of MP3 files, the company said.