Feature Column from the AMS

Barcodes: Using Barcodes

2. Using Barcodes

Among the pioneers of the use of barcodes were Bernard Silver and Norman Woodland, who saw the great potential for use of barcodes in the food distribution industry. The first barcode patent was issued to Silver and Woodland (patent number 2,612,994) on October 7, 1952. The IBM Corporation became aware that the idea created by Silver and Woodland had the potential to be used in conjunction with computers in a variety of settings, and so IBM worked on developing barcode technologies that would promote the sales of computing equipment. IBM had the foresight to realize that barcodes did two tasks well: identify an object and allow information about that object to be associated with it quickly. The barcode that appears on an item in a supermarket does not have the price of the item built into the code (since different stores will sell the item at different prices). However, by using an item's identification number in the barcode, a cash register system can associate a store's price for the item stored in a computer system to quickly display an item's cost to the cash register. If there were a product identification system in barcode form, costs for putting price tags on every item sold in a supermarket for the benefit of the checkout clerk could be eliminated. The barcoded product identification system eliminate the cost of putting price tags on every item for the checkout clerk.

The broad use of barcodes had to await the development of a standard that made it worthwhile for retailers to buy and install the equipment for reading the codes and for manufacturers to invest in assigning codes to their products. One pioneer in making this happen was George Laurer, who helped make the universal product code (UPC) possible. Ever since barcodes caught on, they have been coming into wider and more extensive use. Now that portable equipment for reading the codes and in some cases transmitting this information via a wireless network has become possible, even more uses are becoming available. Examples where barcodes are being used include monitoring blood product and plasma packages by blood banks, containerized shipping, attendance of students at schools, identification tags for patients at hospitals, identification on prescription drugs, checkout of books at a library and tracking of airport luggage. Especially ubiquitous use of barcodes is made in the area of mail and packages. All the express package services track packages using the number attached to them which is read via a barcode at different milestones in the progress of their shipments.

Barcodes are used in a variety of environments where errors can occur. A variety of errors can occur when humans or machines interact with data, but most of the errors are of human origin. Among these are single digit substitutions (e.g. 6 for 9), transposition of adjacent digits (e.g. 34 for 43), transposition of non-adjacent digits (e.g. 34564 for 36544), twinning errors (where the symbols xx in the original are changed to yy), and a variety of other even less frequent errors. When human beings write down numbers such as street addresses, telephone numbers, social security numbers, or the like, there are certain systematic errors that occur. Instead of writing 24th street a clerk may record 42nd street. Instead of writing 739-4022, the number may be recorded 729-4022. Is it possible to design systems that help prevent errors of this kind from having economic consequences? The answer is yes. Nearly al barcodes are designed with the capability of detecting this kind of error. Typically an additional digit is added to the information digits coded into the barcode in such a way that if certain kinds of errors occur, they will be detected. The details of various ways this is done appear below. Not only is it possible to design codes which can detect the occurrence of an error, but one can also design codes which can be used to correct such errors. Traditionally, this has not been done within the rubric of barcode technology.

Like many important technologies, when one looks into how the technology was born, one sees the germs of what was done developing over a long period of time. To implement a barcode system one needed not only the concept of such a data representation technique but the hardware to produce the codes and interpret the information contained in them. The most familiar codes, which are 1-dimensional, have proved so successful that there is now emerging a new generation of 2-dimensional barcodes which promise a wide variety of new barcode applications. The advantage of this newer generation of barcodes is that much more information can be stored in the bars, making a wide range of new applications possible. However, these new types of bar codes require the coordination of the development of applications, standards, and hardware to read and support the applications and standards. There are now commercially available a tremendous number of different barcodes which vary in their ability to encode only numbers, numbers and letters, length, and dimension (i.e. 1-dimensional and 2-dimensional). They also vary in the application to which they are being put.