A pattern of lines or squares that carries an item's number, read by a scanner in an instant instead of typing the number by hand.
A barcode is a way of writing a number so a machine can read it. The parallel black lines on a juice carton represent the product number, and the scanner turns them back into that number and sends it to the computer. Most scanners that plug into a USB port behave like a keyboard: they type the number and press Enter, which is why they work with most programs without special setup.
Barcodes shorten the sale, cut typing mistakes and make a stock count possible in hours instead of days. In Fanann you can build an inventory program that finds an item by its barcode number, and there is a template for printing warehouse labels. Scanners work with the program as long as they type like a keyboard, which most USB ones do. Practical tip: before buying ten scanners, test one: open any text editor and scan a product. If the number appears and the cursor moves to a new line, it will work with your program.