Sony Ericsson will unveil a mobile phone-cum-digital music player early next month. The phone will carry a name which has already appeared on some 350mn music players over the last 25 years: Walkman.

It will play open music file formats such as MP3 and AAC.

To be a success, the music phone must make it easy to browse, select and play music, "and it has to have fantastic sound quality," one of Sony's strengths, a spokesperson said.

The company was tight-lipped about further details, though.

The phone won't be expected to hold an entire music collection. "In our cars, we tend to think six to 10 CDs is enough," the spokesperson said

If a similar capacity is enough for a mobile phone, that would translate to between 250MB and 750MB of storage, at typical data rates for compressed digital music files and assuming the CDs contained between 40 and 75 minutes of music.

Flint expects that, at first, people will rip their own CDs and copy them to the phone, but Sony Ericsson will also work with Sony's Connect online music store to provide a music download service for the phone.

For the last few months, Sony Ericsson has been looking at how to use the Open Mobile Alliance (OMA) DRM specification to stop the phone from being used to make unauthorised copies of copyright music files, and the Connect store is also moving towards OMA DRM, Flint said.

Future phones from rival handset maker Nokia will include the ability to play files in Microsoft's Windows Media Audio format. However, Sony Ericsson would not say whether it has plans to add support for such proprietary music formats.