The c300 from cd3o is fundamentally different from the other candidates in that it merely represents a system to link up a computer and stereo unit. Unfortunately, it can only play audio. Videos are not supported and it was not possible to play uncompressed WAV files. WMA files, though, are accepted and bit rates of up to 320 kBit/s ensure high sound quality.

cd3o has three different models: the c100, that for $129 establishes a connection via a conventional Ethernet interface and transfers analog audio signals to the stereo unit via cinch plug. The c200 ($179), which also features an integrated 802.11b WLAN module and 11 MBit/s, is more flexible. For the test, though, we received the top-of-the-line c300 model, which also features digital audio outputs and an antenna to boost. It costs $199.

A remote control to select audio titles without a computer is included in the package. Before it can work, the control center must be installed on a computer in the network. This releases folders for the cd3o device and enables titles stored on it to be played back directly on the c300. cd3o advertises its independence from players already installed as a feature. However, a plugin for the Windows Media Player in WinAMP would have been worth considering.

The only shortcoming with the c300 audio performance is that there is no title display. Instead, genres, performers, albums and titles can be identified by speech output. As output is optimized for English, German terms and names such "Herbert Grönemeyer" come out so garbled that you have to repeat the process several times to understand what is meant.

The device sorts all available titles based on their ID3 tags. If these contain errors or are incomplete, the file name serves as the sort criterion. Titles with no ID3 information are then stored simply as "unknown artist" or "unknown album". If you have a lot of MP3s, selecting titles will turn out to be an arduous process. What's more, we soon found the speech output annoying.