C64-LINK II is an expansion cartridge for the Commodore 64 that adds 16 disk commands and a machine language monitor to the Cornrnodore 64.  It also allows you to use the "parallel" and "IEEE" modes of data transmission, permitting the use of any parallel printer, IEEE printer or IEEE disk drive.  The C64-LINK II cart ridge takes up no memory and is completely transparent to commercial or home software.