The Dreambox is a Linux-powered DVB satellite, terrestrial and cable digital television decoder (set-top box), produced by German multimedia vendor Dream Multimedia. Its firmware is officially user-upgradable, since it is a Linux-based computer, as opposed to third-party “patching” of alternate receivers. All units support Dream’s own DreamCrypt conditional access (CA) system, with software-emulated CA Modules (CAMs) available for many alternate CA systems. The Dreambox is very similar to the DBox2 units distributed by Kirch Media for its pay-TV services before its bankruptcy; it uses the same Linux-based software originally developed for the DBox2. The built-in Ethernet interface allows networked computers to access the recordings on the internal hard disks on some Dreambox models. It also enables the receiver to store digital copies of DVB transport streams on networked filesystems or broadcast the streams as IPTV to VideoLAN clients. Unlike many PC based PVR systems that use free-to-air type of DVB receiver cards, the built-in conditional access allows receiving and storing encrypted content.
The combination of third-party developers and network connectivity which facilitates card sharing, makes Dreambox use particularly common among enthusiasts and those who intend to obtain services without payment. Third-party software for this purpose is neither officially endorsed nor supported by Dream Multimedia and voids the official warranty; however, unofficial web sites support a very large community of enthusiasts.