Wikipedia
CARDCO was a computer peripheral company during the 1980s in Wichita, Kansas, United States. CARDCO was well known in the Commodore 64 and VIC-20 community because of advertisements in numerous issues of Compute! magazine and availability of their products at large retailers.
There were severe shortcomings of early Commodore printers, so CARDCO created the Card Print A (C/?A) printer interface that emulated Commodore printers by converting the Commodore-style IEEE-488 serial interface to a Centronics printer port to allow numerous 3rd-party printers to be connected to a Commodore 64 or VIC-20, such as Epson, Okidata, C. Itoh. A second model, a version that supported printer graphics was released called the Card Print +G (C/?+G), supported printing Commodore graphic characters using ESC/P escape codes. CARDCO released additional enhancements, including a model with RS-232 output, and shipped a total over two million printer interfaces.