Commodore Compunet Modem
The Compunet modem plugs into the Expansion port of the Commodore 64 or Commodore 128 instead of the Commodore User/RS232 port (used by other modems). A bit strange as the expansion port is usually reserved for ROMs, Cartridges, and other devices which need direct access to the computers bus.
This modem was built for an online service that was only available in the UK, and was manufactured by Commodore UK. It contains an 8k ROM with a special Compunet-service terminal program, though it could also be used with other online services through special terminal software written for the Compunet modem’s unusual interface.