International bar codes

 

Bar codes are something most of us never think about. If you look in your fridge or pantry right now, you will find that just about every package you see has a bar code printed on it. In fact, nearly every item that you buy in a grocery shop, supermarket or superstore has a bar code on it somewhere.

Ever wondered where these codes come from ? What they mean ? And how they work ? You are about to find out.

• History
• How does a bar code work ?
• Universal Product Code (UPC) and European Article Numbering (EAN): what’s the difference ?
• What is the structure of EAN bar codes ?
• What is the structure of UPC bar codes ?
• What are the individual country prefixes in the EAN system ?

Thanks to Conrad H. McGregor for this article, for more information please visit http://users.pandora.be/worldstandards/index.htm

History

In 1948, Bernard Silver was a research student at Drexel Institute of Technology in Philadelphia (Pennsylvania). A local food shop owner had made an inquiry to the Drexel Institute asking about research into a method of automatically reading product information during checkout. Bernard Silver joined together with fellow research student Joseph Woodland to work on a solution.

Woodland's first idea was to use ultraviolet light sensitive ink. The team built a working prototype but decided that the system was too unstable and expensive. They went back to the drawing board and developed something completely different. Finally, on 20 October 1949, Woodland and Silver filed a patent application for the "Classifying Apparatus and Method", describing their invention as "article classification through the medium of identifying patterns". The patent for bar codes was issued on 7 October 1952.

Bar codes were first used commercially in 1966, but it was soon realised that there would have to be a common standard. By 1970, the Universal Grocery Products Identification Code (UGPIC) was written by a company called Logicon Inc. The standard was further improved and led to the Universal Product Code (UPC) symbol set. To this very day, this standard is used in the United States and Canada. In June of 1974, the first UPC scanner was installed at a Marsh's supermarket in Troy, Ohio, and the first product to have a bar code was Wrigley's Gum.

The Universal Product Code was the first bar code symbology widely adopted. Its birth is usually set at 3 April 1973, when the grocery industry formally established UPC as the standard bar code symbology for product marking. Foreign interest in UPC led to the adoption of the EAN (European Article Numbering) code format, similar to UPC, in December 1976.

Currently, the United States and Canada use UPC bar codes as their standard for retail labelling, whereas the rest of the world uses EAN. The Uniform Code Council (the organisation which issues retail codes in the United States) has announced that 1 January 2005 will be the date by which all retail scanning systems in the USA must be able to accept the EAN-13 symbol as well as the standard UPC-A. This change will eliminate the need for manufacturers who export goods to the US and Canada to double-label their products.

 

How does a bar code work ?

A bar code works like a light when turned on in a dark room. You see the walls and furniture in the room by the reflected light from these items. The scanner device directs a light beam at the bar code. The device contains a small sensory reading element. This sensor detects the light being reflected back from the bar code, and converts light energy into electrical energy. The result is an electrical signal that can be converted into data. It is like sonar or radar.

 

Universal Product Code (UPC) and European Article Numbering (EAN): what’s the difference ?

The Universal Product Code has been used in the North American retail industry since 1973. UPC-A and UPC-E are the two main types. The UPC-A bar code is 12 digits long, including its checksum. UPC-E bar codes are special shortened versions of UPC-A bar codes and are 6 digits long. Both UPC-A and UPC-E bar codes may have optional 2- or 5-digit supplemental codes appended to them.

The European Article Numbering system was introduced in 1976. There are two different versions of EAN bar codes, EAN-13 and EAN-8, which encode 13- and 8-digit numbers, respectively. A special EAN-13 bar code with a 5-digit supplemental code is used on books to encode the International Standard Book Number (ISBN) and the price. This bar code is called “Bookland”.

UPC and EAN symbols are fixed in length, can only encode numbers, and are continuous symbologies using four element widths. UPC is in fact a subset of the more general EAN code. Scanners equipped to read EAN symbols can read UPC symbols as well. However, UPC scanners will not necessarily read EAN symbols.

 

 

What is the structure of EAN bar codes ?

EAN-13

An EAN-13 bar code consists of 12 digits for the product code followed by a check digit.

(A) The first 2 (sometimes 3) digits, which are called the “flag”, indicate in what country the bar code was issued. This “flag” does NOT tell you, however, in what country the product was produced. In this case, the bar code was issued in the UK. Click here for an authoritative list of country prefixes.

(B) The next 5 digits indicate the supplier of the product.

(C) Another 5 digits indicate the product.

(D) The last digit is a check digit, which is used to make sure that the bar code reader at the checkout has read the product code correctly.

 

EAN-8

Some products – like a packet of chewing gum, for example – are not big enough to carry the full EAN-13 bar code. That’s why EAN-8, a shortened version of the EAN-13 code, was introduced. This type of bar code has only 8 digits: 2 or 3 digits are used for the country code and there’s also a check digit. This means that only 4 or 5 digits are allowed for the product code (#00000-99,999 or 100,000 products). Thus, only limited numbers of EAN-8 codes are given out in each EAN member country.

(A) The country which issued the bar code is indicated by the first 2 (or sometimes 3) digits, called the “flag”. In this case, the code was issued in Spain. Click here for an authoritative list of country prefixes.

(B) The next 5 digits identify both the manufacturer and the item.

(C) The last digit is the checksum.

 

What is the structure of UPC bar codes ?

UPC-A

A UPC-A bar code consists of 12 digits.

(A) The first digit is a number related to the type of product:

0: regular UPC codes
1: reserved
2: random weight items marked at the shop
3: National Drug Code and National Health Related Items code
4: no format restrictions; for in-shop use on non-food items
5: for use on coupons
6: reserved
7: regular UPC codes
8: reserved
9: reserved

(B) The next group of 5 digits identifies the manufacturer.

(C) The next 5 digits identify the particular product. They are assigned by the manufacturer.

(D) The last digit is the checksum, as in the EAN-13 system.

 

UPC-E

Both EAN-8 and UPC-E are intended for use on small items and consist of 8 digits.

Unlike EAN-8, the UPC-E code is a compressed bar code. Compression works by squeezing extra zeroes out of the bar code and then automatically re-inserting them at the scanner. Only codes containing zeroes are candidates for UPC-E bar codes. Below there is an example of a UPC-A code and its shortened UPC-E equivalent.

In the US, the Uniform Code Council is very stingy when it comes to handing out manufacturer ID numbers with extra zeroes; these are reserved for products which have a genuine need for a UPC-E bar code.

 

What are the individual country prefixes in the EAN system ?

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