In May 1957, Parry began his 30-year career with IBM, mostly in Rochester, Minnesota. While at IBM, he developed devices and systems for high-speed printers, optical character readers, Universal Product Code (UPC) checkout systems, and an Advanced Optical Character Reader (AOCR) which reads addresses from mailed letters and reprints it as bar codes for easy resorting at smaller post offices that have simpler and cheaper sorting machines.