UPC stands for Universal Product Code. It is a standard barcode used in different countries. A Barcode scanner is used to read the UPC and data of a particular product is being identified. The UPC code is found in many packages from grocery stores, department stores, and others.
The UPC barcodes were created earlier for helping the grocery stores in speeding up the checkout process. It was used for keeping track of the inventory. However, it spread to many other industries due to its success. Uniform Code Council (UCC) is the first company that originated the UPC. A manufacturer should apply for the UCC, in order to take the permission for entering the UPC system. An annual fee should be paid for the privilege. Then the manufacturer is given a six-digit identification number along with some guidelines as to how to use it.
The UPC symbol consists of two parts. These include the machine-readable barcode and the human-readable 12 digit UPC number. The first six digits of the code represents the number of manufacturer. The next five numbers represent the product number. The last number is termed as a check digit number. The manufacturer should make different codes for different products. Also different codes should be there for different sized packages of same product. For example the barcode of a 100 gram toothpaste should be different from the barcode of a 200 gram toothpaste.
The last digit or the check digit number allows the scanner to identify whether the correct UPC is given for the product or not. It is possible because the last digit is obtained from doing certain calculations of the other 11 digits.
Let us now consider that a product is scanned by a scanner, say a Symbol barcode scanner. When a product gets scanned by the scanner, the calculation is performed. The check digit is read by the scanner. When the check digit read is different from the calculated check digit, then the scanner would give a false signal. Then the UPC code should be rechecked by the manufacturer or the product should be rescanned until a correct code is obtained. This makes us understand the working process of UPC.