Most barcode scanners consist of three different parts including the illumination system, the sensor, and the decoder. In general, a barcode scanner “scans” the black and white elements of a barcode by illuminating the code with a red light, which is then converted into matching text. More specifically, the sensor in the barcode scanner detects the reflected light from the illumination system (the red light) and generates an analog signal that is sent to the decoder. The decoder interprets that signal, validates the barcode using the check digit, and coverts it into text.
This converted text is delivered by the scanner to a computer software system holding a database of the maker, cost, and quantity of all products sold. This video is a quick lesson in barcode scanners and highlights the basic differences between a Contact Scanner, Laser Scanner, and an Imager.
Because barcode scanners are variable and include diverse capabilities, some are better suited for certain industries due to reading distance and to work volume capacity.