The "CARD/?" (CARD/PRINT) printer interface was designed to all you to add any parallel printer to your VIC-20 or C-64 computer. The design objective was to provide you with a system that would so closely
duplicate the functions of the VIC printers that you would be able to run available software without any changes. To accomplish this task, and still allow you to make use of the special features available in today's
high quality printers, required some special approaches to solving simple problems.