|2D Barcodes Explained|
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For 30 years I have been helping organisations and individuals with their Barcode and Auto ID issues but now I have decided it is time to move on and retire from being the Barcode Man.
I will continue to respond to emails from existing customers about their earlier purchases, their special programming configurations and warranty issues but I regret I cannot help with new purchases or issues nor recommend alternative products or sources.
Lee Allen, The Barcode Man. February 2010
2D Barcode FAQ
What are 2D barcodes?
2D means 'two dimensional'. 2D barcodes contain more information than conventional one dimensional linear barcodes. Conventional barcodes get wider as more data is encoded. 2D barcodes make use of the vertical dimension to pack in more data. 2D barcodes have become possible as auto scanning CCD and laser scanners have replaced the original 'light pen' type of scanner. At this time most conventional CCD and Laser scanners cannot read 2D barcodes but this is likely to change as Barcode Man introduces the first of the range of low cost combined 1D/2D scanners. (See PDF8000 on this web site.)
What is PDF417?
PDF417 is a type of 2D barcode. PDF417 is the name of a specific 2D barcode symbology just as 'Code 39' is a 1D linear barcode symbology.
PDF417 is the latest development in the trend to pack the greatest amount of data in the smallest space. In a very short time PDF417 has established itself as the standard 2D barcode. PDF417 is firmly established as the number one choice for many 2D applications.
What do 2D barcodes look like?
This is a conventional linear barcode. It has a single row of bars- similar to a picket fence. The barcode is called 'one dimensional' because all the data is encoded in the horizontal width. Increasing the data content can only be achieved by increasing the width. Beyond a certain point the barcode becomes too wide to scan easily.
This is PDF417 two dimensional barcode. Data is encoded in both the horizontal and vertical dimensions. As more data is encoded the size of the barcode can be increased in both the horizontal and vertical directions thus maintaining a managable shape for easy scanning.
Will 2D barcodes replace conventional 1D barcodes?
No. Both technologies will co-exist. 2D barcodes will be used where 1D barcodes cannot hold the necessary amount of data but 1D barcodes have the advantage in low capacity applications like serial numbers.
When are 1D barcodes better than 2D?
Although 1D barcodes hold a smaller amount of data it is 'spread' over the whole height of the barcode. The barcode contains a high degree of redundancy. This means the barcode can be read even with considerable degradation. If your application needs only a few characters (up to about 15) then a 1D barcode is probably the best solution. Increasing the height of a 1D barcode does not increase its capacity but it does increase its redundancy thus making it more resistant to degradation and obliteration and making it easier to scan.
How do I create 2D barcodes?
The quest for higher capacity
Since barcodes were first introduced users have wanted them to carry more data per unit area. There are many different barcode symbologies in use today and many of them were introduced specifically to achieve higher data density.
Over the years many techniques have been employed to achieve this but all have had to make some compromises to achieve greater density.
This table shows some of the notable attempts to achieve data compaction and outlines the compromises which had to be made.
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