Thank you for purchasing a SwiftLink-232 serial cartridge! This cartridge contains a 6551 ACIA (Asynchronous Communication Interface Adapter) chip, which allows your computer to communicate with RS-232 serial devices (like modems and printers) at speeds far greater than before. The 6551 is part of the same family of chips (65XX/85XX) found in the Commodore 64 and 128. In fact, the C-64/128’s operating system emulates the 6551. When used with appropriate terminal software, this cartridge allows you to communicate at speeds from 300 bps to 38,400 bps.