MSX Network Interface Card. From the manual: This cartridge transforms your computer into a station in the SVI-609 Local Area Network. These stations are given access to the mass-storage and rapid printing resources of the SVI-609 Master Station. Each slave station can make use of a portion of the SVI-609's 10M-bytes hard disk for its own file storage, and all stations can share a common storage area, printer spooler and software library. [1?]