DreamPi is a piece of software I've written combined with a standard set of hardware which allows the SEGA Dreamcast to connect to the internet without a dial-up ISP.
What You Will Need To build a DreamPi, you need the following hardware:A Raspberry PiAn SD card containing the DreamPi software imageA Linux-compatible, USB dial-up voice modemA telephone cableAn ethernet cableDreamcast browser software (e.g. Dreamkey 3.0)Chances are (regardless of region) you will also need to build a line voltage inducer. This is a simple circuit which sends an electric current down the telephone cable. For this you will need:A 0.47uf capacitorA 380 Ohm resistorA 9v battery connector (two if you have a PAL modem)A 9v battery (two if you have a PAL modem)A soldering iron, some solder, wire strippers, electrical tape, and patience