According to the user manual conveniently linked by buy.com (http://www.terapintech.com/Micar_User_Manual_v1.11.pdf):
- the "USB master" port, for connecting other MP3 players, is disabled (USB slave, to a PC, works)
- LAN port is disabled, "will be enabled later"
- Terrapin Technology http://www.terapintech.com/ doesnt really mention this product, let alone any upgrades. They also list the copyright as 2002(!). Poking around with Google's site search (site:www.terapintech.com) feature finds some FAQs but little else.
It's set up to be upgraded via CD. There's even an "Upgrade" button on the remote! (There's also a serial/USB upgrade connection...)
Basically, it's a $100 CD/MP3 player/recorder/copier with a remote. It'll also record and/or compress external audio, or convert audio to mp3 or back or just duplicate tracks.