01 Barcodes

We all know bar codes. For several decades now, the bar codes have been emblazoned on all goods to reveal to the beeping cash register exactly what wants to be bought. With the spread of smartphones, we got another barcode in our everyday lives in the form of the square, black-and-white data matrix boxes, which now promise further links and information everywhere on billboards and in newspapers (but unfortunately often fail to deliver on this promise – the creators of these codes usually fail to provide more than just a simple link).

In addition to these two well-known barcode variants, there is a plethora of others, which of course the technophile cachers do not stop at in order to make their information as unreadable as possible. However, these contents are not really encrypted, but you usually need suitable software on your smartphone or PC to elicit human-readable barcode information. Of course, this can usually be done with brains and knowledge, if you only know how a certain barcode is structured and which one you are trying to decode. The code list from which Code 39 is constructed can be admired at Wikipedia – Code 39. It is also available as a ttf font.

If you have the world-wide web at your disposal, you will be almost overwhelmed with websites offering at least the standard codes for translation. If it gets a bit more complicated, the code is less readable, I like to use the software bcTester. When I’m on the road, I’ve found that multiple barcode readers in the smartphone are the better choice. Several smartphones are the best. In the worst case, you can also photograph what you find and – hopefully – read and decode it with another device.

Barcodes originated from the requirement to be able to attach machine-readable information that is as unambiguous as possible. For this reason, the well-known EAN commodity codes contain checksums, so misreading is almost impossible. Otherwise, this code contains only digits, represented in bars and gaps of different widths. Other codes can also represent ascii characters or extended character sets. The most content can be found in the two-dimensional codes, the datamatrixes.  

Here is a small and by no means complete overview of better-known barcodes

EAN numeric code 0-9

Dashes and spaces contain information, 8 or 13 characters

Code 39

Alphanumeric code, 0 – 9, 26 letters, 7 special characters. Each character consists of 9 elements (5 dashes and 4 gaps, 3 wide, 6 narrow).

Code 128

Full ASCII character set using 3 character sets selected by a start character. Consists of 11 characters divided into 3 dashes and 3 gaps.

Code 2/5 Interleaved

Numeric code 0-9, consists of wide and narrow bars and gaps.

German Post Identcode:

Numeric code, 0-9, 12 characters long, check digit.

Code Postnet

US Post Office code, numeric code, 0-9 representable. Checksum, start and stop
stop characters.

Code Royalmail

contains digits 0-9 and 26 Latin letters. Code “kix” looks very similar to this

Target code

is used by Deutsche Post

Code PDF417

Stack code with strong error correction. Consists of individual elements, the “code words”, each of which consists of 17 modules divided into 4 bars and 4 gaps.


stacked code39/128. Each line has a line indicator (same start) and checksum.


Variable rectangular size between 10×10 and 144×144 characters. Contains the extended ASCII code. Horizontal and vertical border describes a corner for orientation of the reader.


Marking in 3 of 4 corners for orientation of the reader. Large error tolerance. Ascii-character.

Aztec: Numbers and letters arranged in a circle around the centre.


hexagonal characters around round centre. Contains up to 93 alphanumeric or 138 numeric characters. Large error tolerance. Similar to beetag code.

Microsoft Tag

Single coloured code, can look very different, can also be integrated into images. Closed code, generate and read only via paths provided by Microsoft

Weitere Codebeispiele:

  • http://www.logicalconcepts.eu/wDeutsch/autoid/barcodetypen/index.html?navid=21
  • http://www.activebarcode.de/codes/

Wer gerne selber Barcodes unter Windows erstellen möchte, dem kann ich (Stand: Erstellung dieses Blogbeitrages) den Zint Barcode Generator empfehlen. Simpel, selbsterklärend und erstellt über 50 verschiedene Barcodes.