Rockwell Automation 2755 Cordless Hand-Held Scanner - Manual (Page 102)

Glossary G–5
Publication 2755-6.3
Symbology
The structural rules and conventions for representing data within a
particular bar code type (e.g. UPC/EAN, Code 39).
U
UPC
Universal Product Code. A relatively complex numeric symbology.
Each character consists of two bars and two spaces, each of which
can be one of four widths. This is the standard symbology for
retail food packages in the United States.