Bar Code SymbologiesAppendix —B
369TE 2000
5250 Terminal Emulation Programmer’s Guide
Code 39
Code 39 (C39) is the most widely used symbology among the industrial
bar codes. Most major companies, trade associations, and the federal gov-
ernment find this code to fit their needs. The main feature of this symbol-
ogy is the ability to encode messages using the full alphanumeric character
set, seven special characters, and ASCII characters.
Programming for this symbology can be for any length that the application
requires. The application program handles symbology that is at least one
character but no more than 32 characters in length.
When programming the computer for Code 39, it is important to set the
symbology limit as close as possible (minimum and maximum bar code
lengths being scanned). Doing so keeps the computer bar code processing
time to a minimum and conserves battery power.
Bar code readers can respond to Uniform Symbology Specification sym-
bols in non-standard ways for particular applications. These methods are
not for general applications, because of the extra programming required.
Code 39 Full ASCII is one example of non-standard code.
EncodedCode39(Concatenation)
If the first data character of a symbol is a space, the reader may be pro-
grammed to append the information contained in the remainder of the
symbol to a storage buffer. This operation continues for all successive sym-
bols that contain a leading space, with messages being added to the end of
previously stored ones. When a message is read which does not contain a
leading space, the contents are appended to the buffer, the entire buffer is
transmitted, and the buffer is cleared.
EncodedCode39(FullASCII)
If the bar code reader is programmed for the task, the entire ASCII charac-
ter set (128 characters) could be coded. This is done using two character
sequences made up of one of the symbols (“$”,“.”,“%”,“/”) followed by
one of the 26 letters.
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