Most bar codes encode information in line width although at least one draws a baseline and encodes information in the length of perpendicular lines. Many bar codes can be generated by ordinary printers using special fonts.
UPC, ISSN, EAN, and JAN are retailing codes used in various parts of the world/business to read pricing, inventory, etc. Code 39 is a widely used alphanumeric code. Postnet is used by the US Post office. Other codes, some proprietary, are used where compactness or other properties are desired.
Bar Code Scanners generally use a low power red or infrared laser and read the reflected light. Scanners contain a light source, light receiver, optics, a display device and often some sort of data connection. A microcomputer is often included. Since the size of production runs is limited compared to consumer devices, prices are roughly comparable to those of personal computers rather than to those of small consumer devices. Many scanners are capable of handling multiple codes.
Return To Index Copyright 1994-2002 by Donald Kenney.