2D Barcode FAQ

“All the barcodes on this page were created with Bartender software. You can get it here”

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?

Conventional 1D barcode (Code 39)

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.

2D Barcode (PDF417)

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?

2D barcodes are relatively new. You will need to use special barcode generation software. Barcode Man recommends the 'Bartender' package. All the barcodes on this page were generated with Bartender.

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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.

All barcodes printed to the same scale	Char Count	Comment
	10	These are conventional one dimensional Barcodes. The symbology is Code 39. Both barcodes contain 10 data characters. Code 39 can encode both numeric and alphanumeric data. However the alpha characters are single case (usually defined as upper case). If lower case characters are required then 'Full ASCII Code 39' must be used and the barcode increases in size as shown in the second example.
	10
	10	This 'Interleaved 2 from Five' barcode can encode data characters in about half the space required by the best Code 39. However the symbology cannot encode alphabetic characters at all. Only numerics are permitted.
	10	Code 128 barcodes can encode both alpha and numeric characters. The numerics can be encoded in compact form similar to Interleaved 2 from 5. However if alpha characters are included in the barcode its size increases by about 50%. Nevertheless this is still an improvement over Code 39. Furthermore All the ASCII character set can now be encoded without further size expansion of the final barcode. Code 128 is about the best that can be achieved with one dimensional barcodes.
	10
	10	This is a two dimensional Barcode. Symbology PDF417. It contains the same number of data characters as all the preceding barcodes... ABC1234xyz With this number of data characters there is no advantage over conventional barcodes.
	62	The point where 2D barcodes should be used rather than 1D occurs somewhere between 10 and 20 data characters depending on particular circumstances. The PDF417 barcode opposite encodes all these characters... ABCDEFGHIJKLMNOPQRSTUVWXYZ 0123456789abcdefghijklmnopqrstuvwxyz This is much more than can be achieved with a conventional barcode while still retaining a manageable barcode size.
	249	Whilst it is prudent to minimise the number of data characters encoded in the barcode this example shows what can be achieved with PDF417. The barcode opposite encodes the following rhyme from Lewis Carol's Alice in Wonderland. 249 characters in total, including punctuation and line-end characters... Tweedledum and Tweedledee Agreed to have a battle; For Tweedledum said Tweedledee Had spoiled his nice new rattle. Just then flew down a monstrous crow, As black as a tar-barrel; Which frightened both the heros so, They quite forgot their quarrel.