The barcode is nothing more than the graphic representation of the sequence of digits that is printed just below it. The advantage of bars is that they can be identified quickly, and without risk of error, by portable optical reading devices, such as those used by supermarket cashiers. But what really matters to identify the product is its numerical sequence, which can also be entered manually by the cashiers.
“This number works as a kind of product ID, that is, there are no two different products with the same number”, says industrial designer Cláudia Ferreira, consultant for EAN, an international organization that managed the distribution of codes in the world and has a representation in Brazil. Currently, the EAN standard is under the care of GS1, a non-profit organization that creates global standards for business communication.
The bar system was created in the United States in 1973 and ended up being adopted in Europe three years later. But while Americans use a 12-digit numerical sequence, Europeans opted for a 13-digit pattern, which has been adopted in the rest of the world.
As of 2005, however, the two systems were unified. But this does not mean that all numerical confusion is over, as there are still other types of special codes, such as the eight-digit EAN-8 (used when the product packaging is very small).
cipher language
The bars are a graphical representation of the binary code. Each black or white dash is equivalent to a bit (1 or 0, respectively) and each digit is always represented by seven bits. A dark bar that is thicker than the others is actually the sum of several black lines. The same principle applies to the white bars.
INITIAL NOTICE
These first three longer bars (a white one in the middle of two black ones) are a signal, indicating that the product code comes next. The slashes and their respective digits are not aligned – that is why the number 7 comes before the signal bars.
NATIONAL REGISTRATION + MANUFACTURER’S RG
The first three numbers (789) indicate that the product was registered in Brazil, although it was not necessarily manufactured here. Each country has its own combination. Argentina’s, for example, is 779.
Still in this initial sequence of numbers, which can vary from seven to eleven digits, is the identification of the manufacturing company. This number is provided by an international organization, GS1, which controls that equal numbers are not distributed.
PRODUCT ID
The second string identifies the product itself. The numbering varies according to the type, size, quantity, weight and packaging of the product – a Coke in a can, for example, has a different sequence than one in a bottle.
FINAL CHECK
The last number is a check digit. When reading the entire product code, the computer makes a complex calculation, adding, dividing and multiplying the previous digits. If the reading is correct, the result of this strange calculation is the same as the check digit.