*3.3.3. Barcode*

The barcode system uses a barcode scanner to interpret the value in the barcode label to obtain a unique code that is used for object identification [7]. Barcodes are "optical machinereadable labels attached to items to record information about them, and they are usually read by laser scanners" [7]. Three types of barcodes exist: *alpha numeric* used for encoding numbers and characters, *numeric* used for encoding pairs of numbers, and *2-dimensional*, which looks like squares or rectangles that contain many small, individual dots [7]. The disadvantage of this system is the line of sight requirement between the barcode and the reader [10, 13].
