The various forms and functions of barcodes – from retail to the military (Part Two)

In yesterday’s post we explored some of the uses and workings of retail barcodes – today we explore some more linear and 2-dimensional barcodes: Code 3 of 9, Code 128, ISBN & ISSN, DataBar, Interleaved 2 of 5, Data Matrix & QR Codes, Aztec Code, PDF417, Postnet and MaxiCode as shown in the picture alongside… Read Part One here.

Let’s have a look at the varied and sometimes amazing ways that barcodes have been used to track everything from post and parts in warehouses, to medicines and prescriptions and batches donated to blood banks. The record for the world’s smallest barcodes goes to a company called Data2 who developed miniaturised barcode labels to track the movement of bees. The tiny labels, which weighed only one-twentieth of the bees normal pollen load, were specifically shaped to fit the bee’s thorax and some of the bars where only a thousandth of an inch in width. A scanner was affixed to the tunnel-shaped entrance to the bees’ hive and scanned the bees as they flew in and out. Other commonly used barcode formats – or symbologies – include:

LINEAR BARCODES:

Codabar / Code-a-bar:

Shipping and courier companies as well as libraries and blood banks make use of this barcode. It was developed back in 1972, and whereas newer symbologies are often used in its place today it is still widely used in libraries. It contains no check digit as it is a self-checking numerical barcode format. 

Code 39 / 3 of 9:

This code is also an older symbology but is still widely used for tracking and inventory purposes. There is an optional check digit but this is rarely used. Unlike UPC, EAN and Codabar formats, this barcode symbology supports both numeric and alphabetic characters as well as a few punctuation symbols. Unlike a retail barcode the stop and start digits are represented by an asterisk rather than by the ‘guard bars’. Interestingly it is the format widely used by the United States Department of Defense to mark all products which they purchase.

Code 128:

This code enjoys wide use within the shipping industry. Its popularity comes from the fact that it is dense and compact while still being able to include a lot of data. It includes a check digit and supports a wide range of alphanumeric characters. When used in what is called Code 128 C – which contains numeric digits only – it effectively doubles the density of a normal numeric barcode. There is also a special GS1-128 version of this symbology available that includes GS1 element strings.

ISBN – International Standard Book Number barcodes:

This is a 13-digit barcode which is allocated to once-off publications such as novels, non-fiction books, e-books and the like. It allows bookstores and libraries to track the title and edition of a particular publication. Each unique version of a book – say the hard- and soft-cover versions – will have a different ISBN number. They look very similar to a normal EAN barcode and use the same symbology or barcode ‘font’. They can contain an optional 5-digit supplement code which may be used to indicate the price of the book.

ISSN – International Standard Serial Number:

This code originally begin as a normal UPC barcode with an additional code holding a system ID Code – this meant that more information about the product – such as expiration date, serial number, company ID or GTIN (Global Trade Item Number), lot number, and similar information could be read at the scanner. The square shape also allowed for smaller labels to be scanned on items such as fresh produce and small cosmetics. Today their most common usage is as ‘coupon codes’ – allowing the cashier to deduct the relevant offered discount upon checkout. The small PDF417 code which you see between the two linear barcodes contains no information and is simply there to prevent ‘cross-scanning’ of the two linear barcodes – these barcodes cannot be read by two-dimensional scanners. These barcodes come in a range of forms, which can be made up of 1 – 3 separate ‘tiers’. Some of the forms used in retail include GS1 DataBar Ominidirectional, Stacked Omnidirectional, GS1 DataBar Expanded and DataBar Expanded Stacked.  

Interleaved 2 of 5 Code or I25:

A Data Matrix code is 2-dimensional, unlike the barcodes discussed above. They look very similar to the popular QR codes that we are all familiar with although they are quite a bit smaller and are used where a lot of information needs to be displayed in a very limited space. This made them very popular with government departments in the US. However the fact that their design – which allows for the use of over 2300 alphanumeric characters – did not include Japanese (or Kanji) characters ultimately led to the invention of the QR Code, which can contain around 4200 characters including the Kanji alphabet symbols.

Aztec Code:

This code was invented in 1995 and today is mainly used in the tracking and sorting of packages and parcels in the transportation industry. The central square finder patterns gives it its name due to the resemblance it holds to the Aztec pyramids. Its main benefit is in size the reduction of the barcode due to the fact that it does not require a surrounding ‘quiet’ zone of blank space. This is because the sizing information of the barcode can be read from the number of pixels in the central core. The central square grid is also used to locate the barcode, and include orientation marks at the corners which mean that the code can be read even when rotated. It is of course also well suited for display on smartphones and tablets, making them useful for electronic traveller’s tickets.  

PDF417 (Portable Data File):

This is the barcode which forms the honey-comb like pattern often found on driver’s licenses and other forms of identification. It is what is referred to as a ‘stacked’ linear barcode – meaning it is basically rows of linear barcodes on top of each other. The ‘4’ in the name indicates that each pattern contained in the code consists of four bars and spaces, and that each of these are 17 units long.

Postnet (Postal Numeric Encoding Technique) barcodes:

This symbology is utilised to incorporate the zip code, delivery point and usually the last two digits of the PO Box number or address of items to be delivered by the US Postal Service. These barcodes are slightly different from the normal variety as the bars which they are made up of vary in height and not in width.

MaxiCode (also known as UPS Code or Bird’s Eye Code):

As with the Aztec Code symbology discussed above, these codes are widely used by postal services such as UPS to track and sort packages. They consist of the central finder pattern and rows of hexagonal modules. They include a primary and secondary message – meaning that country and postal code as well as delivery address date can both be included – although they can be used to encode many other types of data. The MaxiCode symbology has built-in error correction meaning that even when a package has been slightly damaged during transit that the information contained can still be decoded. The concentric circles mean that the code can be scanned at any orientation – making them extremely quick to scan and therefor useful for urgent deliveries.There are many other symbologies which exist either for very specific industries or applications or which have become obsolete with the emergence of 2D barcode formats. If you look at the amazing variety of formats already in existence it is interesting to ponder where the future of barcodes may lie. So much data can already be captured by a two dimensional format – imagine a future where 3D barcodes become a reality…