This article is from the source 'bbc' and was first published or seen on . It will not be checked again for changes.

You can find the current article at its original source at http://news.bbc.co.uk/go/rss/-/1/hi/magazine/5362740.stm

The article has changed 2 times. There is an RSS feed of changes available.

Version 0 Version 1
How do 2D barcodes work? How do 2D barcodes work?
(about 3 hours later)
WHO, WHAT, WHY? The Magazine answers...WHO, WHAT, WHY? The Magazine answers...
The barcodes hold far more dataWe can now buy postage online, instead of using stamps, but how do two dimensional barcodes work? And what's to stop you photocopying them?The barcodes hold far more dataWe can now buy postage online, instead of using stamps, but how do two dimensional barcodes work? And what's to stop you photocopying them?
No queuing at the Post Office for a stamp, it's a dream come true.No queuing at the Post Office for a stamp, it's a dream come true.
Customers can now pay for postage by credit card over the internet for first-class, second-class, recorded, special and international deliveries.Customers can now pay for postage by credit card over the internet for first-class, second-class, recorded, special and international deliveries.
Each item of mail is given a two dimensional (2D) barcode, printed off onto an envelope and regular mail can then be posted in a post box. Recorded and special delivery items must still be taken to a Post Office.Each item of mail is given a two dimensional (2D) barcode, printed off onto an envelope and regular mail can then be posted in a post box. Recorded and special delivery items must still be taken to a Post Office.
And forget thoughts of photocopying - the barcodes cannot be used again as each is unique and is scanned when it reaches a sorting office.And forget thoughts of photocopying - the barcodes cannot be used again as each is unique and is scanned when it reaches a sorting office.
Dots and linesDots and lines
A single pack of chewing gum was the first retail product sold using a barcode and scanner, at a supermarket in Troy, Ohio, in June 1974. It had a conventional linear barcode, so how do the newer 2D ones work?A single pack of chewing gum was the first retail product sold using a barcode and scanner, at a supermarket in Troy, Ohio, in June 1974. It had a conventional linear barcode, so how do the newer 2D ones work?
WHO, WHAT, WHY? A regular feature in the BBC News Magazine - aiming to answer some of the questions behind the headlines These were first introduced by US firm Intermec Corporation in 1988 and hold far more data in a small space, typically 1,000 characters compared to 20 characters on a traditional barcode. WHO, WHAT, WHY? A regular feature in the BBC News Magazine - aiming to answer some of the questions behind the headlines These were first introduced by US firm Intermec Corporation in 1988 and hold far more data in a small space, typically 1,000 characters compared with 20 characters on a traditional barcode.
All barcodes encode a string of characters as a set of bars and spaces. Linear barcodes get wider as more data is encoded, but 2D ones encode data in both the horizontal and vertical dimensions.All barcodes encode a string of characters as a set of bars and spaces. Linear barcodes get wider as more data is encoded, but 2D ones encode data in both the horizontal and vertical dimensions.
Visually the barcodes look like lots of small black and white squares in an area similar to the size of a postage stamp.Visually the barcodes look like lots of small black and white squares in an area similar to the size of a postage stamp.
Unlike standard barcodes, which depend on links to a larger database, they contain a sort of mini-database themselves, which includes information on the product and can be encrypted.Unlike standard barcodes, which depend on links to a larger database, they contain a sort of mini-database themselves, which includes information on the product and can be encrypted.
As more data is packed in, the size of the barcode can be increased in both the horizontal and vertical directions, which makes it much easier to manage the shape for scanning. Data can even be read if part of the barcode label is damaged.As more data is packed in, the size of the barcode can be increased in both the horizontal and vertical directions, which makes it much easier to manage the shape for scanning. Data can even be read if part of the barcode label is damaged.
Other ways 2D barcodes are being used include Smart Ovens, produced by Samsung. They read special 2D barcodes - known as SmartCodes - on food packaging which tell the oven how to cook the food, including the correct temperature, microwave power and time.Other ways 2D barcodes are being used include Smart Ovens, produced by Samsung. They read special 2D barcodes - known as SmartCodes - on food packaging which tell the oven how to cook the food, including the correct temperature, microwave power and time.