Flash-memory-equipped headphone portables bring mobility to MP3 and other compressed formats used to transmit music files over the Internet or to record music from a CD onto a PC's hard drive.
Flash-memory portables, priced anywhere from $99 to $199 including PC player software, are legal, according to a decision by a federal appeals court, but the music industry hasn't ruled out an appeal.
The portables can be designed to store music in one or more compressed formats such as MP3, RealNetworks G2, and Microsoft's MS-Audio, but to date. most play only MP3.
In the portables, music can be stored in embedded flash memory or in plug-in memory cards conforming to such standards as CompactFlash, SmartMedia or MultiMedia Card.
On top of incompatible compression formats and storage media, portable manufacturers haven't even agreed on a single way to write compressed music files to the cards, according to Sensory Science. As a result, someone who uploads music in MP3 format to a brand-X MP3 player's CompactFlash card shouldn't expect to plug that card into a friend's brand-Y CompactFlash-equipped MP3 player and hear music.
Despite the incompatibility issues, flash-memory portables have an advantage over their disc-spinning counterparts: The lack of moving parts makes mistracking impossible and potentially allows for longer battery life than what can theoretically be achieved by headphone CD and MD players.