A Barcode reader or Barcode scanner is an electronic input device which is able to scan and decode barcodes. These devices use optical technology such as infrared light. Some readers use an integrated decoder, others have one unit for reading the barcode, and another one to decode the barcode. A barcode reader, also called a price scanner or point-of-sale ( POS ) scanner, is a hand-held or stationary input device used to capture and read information contained in a bar code . A barcode reader consists of a scanner , a decoder (either built-in or external), and a cable used to connect the reader with a computer. Because a barcode reader merely captures and translates the barcode into numbers and/or letters, the data must be sent to a computer so that a software application can make sense of the data. Barcode scanners can be connected to a computer through a serial port , keyboard port , or an interface device called a wedge . A barcode reader works by directing a beam of light across the bar code and measuring the amount of light that is reflected back. The dark bars on a barcode reflect less light than the white spaces between them. The barcode scanner then converts the reflected light energy into electrical energy, which is converted into data by the decoder and forwarded to a computer.