Bar code representation has existed since the early days of computer development, but its application in information entry is comparatively recent. The universal product codes used in supermarkets and department stores is the first example of its application, and application in other areas seems to be increasing. Bar code scanning as an information entry method can be highly accurate and complementary to traditional keyboard, tablet and optical character recognition input techniques. In this paper, the various bar codes, their design principles and the technical issues involved in determining their applicability are discussed along with a comparison with other technologies. The general application of bar code scanning and its use with the Chinese language are also explored. © 1983.