This device, manufactured by Nokia, Philips and Sagem in huge numbers for the German Pay-TV provider Premiere, is a DVB-C or DVB-S receiver. It features a 10Mbit Ethernet interface and a nifty graphics display, on which you can display your Linkstation logs. The device is unique in that it runs a user upgradable version of Linux.
LinkStations are popular among DBox hackers, since they can be used to record received media streams from a DBox. See the Linux-based Tuxbox project wiki.tuxbox.org (German) for information about DBox hacking. This was once the main reason for people in Germany to buy a LinkStation.
In case you own a Panasonic DVD recorder, you might want to check out andre's instructions.
If you're interested in speeding up your Picture Viewer (Bildbetrachter), check out these installation or compilation instructions.