2-D BAR CODES
In 1974, the first bar code was scanned. It was printed on a pack of chewing gum. It was a significant event. Almost immediately, UPC bar codes began to appear on hundreds of other products. Supermarkets and other large stores quickly
installed machines to scan these bar codes. These machines were called scanners. They were linked to store computer systems. UPC and other bar code formats are one-dimensional. That is, the information coded in the black and white pattern of lines can be read in only one direction. There is a beginning to the pattern and an end to the pattern. The information in the pattern identifies only the product and its manufacturer. After a while, companies wanted to find a way to include more information in the bar code.