Barcoding
Since their invention in the early 1950s bar codes have accelerated the flow of products and information throughout the global business community. In construction, bar codes are used for identification and tracking of construction components. All barcode system needs can be determined by asking two questions, (1) how and where will the barcodes be printed, and (2) how and where will they be read.
Scanners: Contact scanners require physical contact with the barcode. Non-contact scanners can read barcodes from a distance. General purpose laser scanners can read barcodes from a distance of 4 inches to 18 inches away. High performance scanners can read barcodes from 7 inches to a distance of 20 feet.
Symbologies and Resolution: A barcode is a message that holds information. The structure of the barcode consists of the height and the width. Information is encoded into spaces and bars of various widths. The height of the barcode does not hold any information. Using the height, however, the barcode can be enlarged for easy scanning or for better visibility. The number of characters are represented in a linear inch called the barcode density. The density depends on the symbology. For example, using Code 39, 9.4 characters can fit in one inch, and when using Interleaved 2 of 5, 17.8 characters can fit in one inch.