Code 39 - Full ASCII

Code 39 - Full ASCII

The Code 39 - Full ASCII (pronounced "ASK EE") symbology is similar to Code 39 - Regular. To successfully print and read Code 39 - Full ASCII, the barcode object on the label format file must have "Code 39 - Full ASCII" selected as the symbology to print. In addition, the barcode reader being used to scan the barcode must be configured to perform Full ASCII character translations.

The Character Set

Both the Code 39 - Regular and the Code 39 - Full ASCII barcode symbologies contain the same 43 character set, as well as the same start and stop characters. However, Code 39 - Full ASCII uses special two-character combinations from the 43 character set to allow for the representation of all 128 ASCII characters. In other words, you can encode any of the standard (not the extended) characters from the computer's keyboard into a barcode, as well as the ASCII control characters.


Let's take a look at printing lowercase letters. No lowercase letters are native to the Code 39 character set, only capital letters. Therefore, when printing Code 39 - Full ASCII, lowercase letters are represented by generating the barcode symbol for a plus sign (+), followed immediately by the barcode symbol for the uppercase version of the letter. So, to print the letter "a", you would actually print a barcode containing "+A".

Now, suppose we scan the barcoded Code 39 - Full ASCII "a" that we printed as described in the previous paragraph. In Full ASCII mode, the barcode reader would decode the plus sign, and then, rather than transmitting it, would look at the next barcode character symbol (in this case a capital "A") and perform a Full ASCII conversion. The barcode reader would then transmit just the lowercase "a".

If the barcode reader had Full ASCII translation disabled, no translation would be performed and the actual characters "+" and "A" would be transmitted.

Character Density Loss with Code 39 - Full ASCII

While Code 39 - Full ASCII has the advantage of representing all 128 ASCII characters, it does sacrifice barcode character density to do so. When encoding into Code 39 barcodes any characters that are native to the 43 character set, your barcodes do not undergo any degradation in character density. However, since each Full ASCII character is represented by a 2-character combination, the more of them you use, the more space you need for your barcodes. For example, the word "SEAGULL" is encoded into barcode as *SEAGULL*, but the word "seagull" is encoded into barcode as *+S+E+A+G+U+L+L*, which takes about twice as much space.

The Start and Stop Characters

Code 39 - Full ASCII also has a "start/stop" character. This character is used at both the beginning and the end of the barcode message to signal a barcode reader that a Code 39 - Full ASCII barcode has been scanned. This character is commonly designated as an asterisk (*), but you may choose to have no start/stop characters at all or choose to let the data source specify the start or the stop character, or both. The start and stop character are not transmitted as part of the barcode, and is not included in any check digit calculations.

Code 39 - Regular

More barcode symbologies

More Information

Webinar Series:
Easy data integration with the BarTender Integration Builder 
Recorded webinars available now!

BarTender Overview

What's New in BarTender 2016

Compare Editions

Get Technical Specifications

Buy BarTender

Upgrade BarTender

Register BarTender

Get Technical Support

Get Printer Drivers

Barcode Software

Our Customers Say

"BarTender’s ability to integrate with any ERP and Safety Data Sheet authoring and management system, coupled with its easy-to-use and powerful Intelligent Templates™, has made it our go-to software product for integrating and solving the challenges associated with GHS compliance labeling in all of our chemical customers."

—Rick Schilling, President, Integrated Productivity Systems (IPSi)