Almost everyone of us must have heard, if not seen or known what it is, bar code numbers from somewhere or the other. Or you haven’t? Yes, that pattern of black lines with white spaces in between and some numbers appearing beneath the bars and found in almost every manufactured product we purchase in the market. We simply call it bar code, but it is actually called the Universal Product Code (UPC).
So what is UPC barcode or bar code numbers? What do they mean and what do they represent? Well, the lines as well as the numbers have meaning. While the bars are for machines to ‘read’, the numbers are for humans.
The original design of the bar code numbers called for a classification number (the left outside number), the manufacture code (the left group of 5 digits), the product code (the right group of 5 digits), and a check digit (the right outside number).
Simply put, the first six numbers are related to the manufacturer and the type of transaction, the next five describe the product or item number. The last number is the check digit, which is used to validate or ensure that all of the other numbers have been read correctly by a scanner.
What about the bars?
Notice that there are four different widths of bar in any UPC code. Each of the four sizes corresponds to a value of one to four. So a black line followed by a white line followed by another black line is three ‘ones’. This is how all UPC codes begin. After this ‘start code’, every sequence of 4 line widths corresponds to binary code for one of the numbers that appear beneath the bars. The last three digits are once again three ‘ones’.
Hope, now you know what bar code numbers mean and what they represent.