SmartDisk is developing a technology called FlashTrax to play MP3s on car stereos or old Walkmans.

FlashTrax will mean no laborious conversions from MP3 to .wav and dubbing to cassette tapes.

The company this week demonstrated a prototype of FlashTrax, which looks like a conventional audio cassette. The difference is a slot in its side, where a flash memory card holding standard MP3 files can be slotted in.

FlashTrax should be available by this Autumn, SmartDisk representatives said. Two configurations are expected - an accessory to existing portable MP3 players, and a complete package with software and hardware for recording onto flash memory cards, as well as onto the cassette. The company is aiming at a price "well below the street price" of portable MP3 players.

The technology behind FlashTrax is sophisticated and protected by several patents, says Douglas Kraul, SmartDisk's vice president of audio/video products. The process isn't simple, because today's cassettes and cassette decks are more complex than they appear, he adds.