Code 39

Code 39 is by far the most common barcode scheme outside the retail area and is read by most scanners, although it is not as compact as Code 93 or Code 128. The normal Code 39 scheme encodes both numbers and upper case letters, and was the first alphanumeric symbology:

 

  Standard Code 39

 

Code 39 has an optional Mod 43 checkdigit.

The Extended Code 39 scheme also includes the lower case letters and much punctuation.

 

     Extended Code 39

 

It should be noted that Extended Code 39 represents most of the additional characters by using two characters from the standard Code 39 character set. Consequently Extended Code 39 symbols are about twice as long as standard Code 39 symbols.

Code 39 is a discrete symbology - so the gap between ciphers may be larger than a unit space. Some users mistake that inter-cipher gap for a space and become concerned because it is not the same size as in another barcode representing the same characters. There is no substitute for testing the barcode with a scanner!

Also the start and stop characters are the same, and sometimes may be represented in the human readable form by an asterisk.

If iExtra1 is set the start and stop characters are shown as an asterisk in the human-readable form.

If iExtra1 is not set then the start and stop characters are not represented in human-readable form.

If iExtra2 is set an inter-cipher gap of 1 unit is used. If iExtra2 is not set there is no inter-cipher gap.

 

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Code 93