Americans Bernard Silver and Norman Woodland conceived of the first barcode system in the 1940s, but a practicable system was not feasible until George Laurer developed a scanner that could read barcodes years later. The first standardized barcode adopted for general use was the linear Universal Product Code (UPC), chosen by North American supermarkets in 1973. It entered commerical use in 1974, and became widely deployed in the 1980s. The original UPC used a set of two dark (usually black) and two light (usually white) bars of specified thicknesses to represent 12 numbers, but beginning in 2005 the Uniform Code Council, now known as GS1 US, adopted the similar European Article Numbering Code (EAN), which encodes 13 numbers and had become the international standard. The standards for the international product barcode system are managed by GS1, formerly known as EAN International, which is based in Brussels. The dark bars may be from one to three units wide and the light bars from one to four units. For registration purposes two one-unit dark bars are placed at each end and in the middle. Each item is assigned a unique numeric code, which is printed as a barcode on the item's packaging.
So-called two-dimensional (2D) barcodes permit the encoding of information about an item in addition to an identifying code. In a 2D barcode, two axes, or directions, are used for recording and reading the codes and the bar size is reduced, increasing the space available for data in the way that a column of words improves on a column of letters. Some 2D codes do not use bars, such as the United Parcel Service's hexagon-based Maxicode. Manufacturers and others now use 2D Quick Response (QR) codes on products and other objects to provide information associated with those items directly to individuals who can read the barcodes using smartphones. QR codes are also used for a variety of other purposes.
Radio-frequency identification (RFID) could supplant the barcode in most applications. Radio-based devices overcome many of the limitations inherent in the barcode's optical technology.
The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2012, Columbia University Press. All rights reserved.
See more Encyclopedia articles on: Computers and Computing