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Extended Code 39

Extended Code 39 was developed to provide a means of encoding additional characters that are not normally part of the Code 39 character set (lower case characters and symbols).  Extended charcters are encoded by a pair of normal Code 39 characters. For example, a lower case 'a' (not part of the standard Code 39 character set) can be encoded by the pair '+A'.  A carriage return control code can be encoded by the pair '$M' (see table below).

Be very cautious about using Extended Code 39; it should be used only in closed systems where you have control over all the scanning stations.  The barcode provides no indication of whether it should be interpreted as normal or extended Code 39.  Unless a scanner is configured correctly, barcode data can be misinterpreted.  For example, '123+ABC' could be interpreted as '123+ABC' (normal) or '123aBC' (extended).

Extended Code 39 can be wasteful of space since each extended character requires two barcode characters.  Note that the letters A through Z and the digits 0 through 9 are encoded as single characters, just as in standard Code 39.  Space may not be a problem if only a few extended characters are required, but as the number of extended characters increases a barcode can grow to almost double its normal length.

Unless there are compelling reasons for using Extended Code 39, Code 128 (which includes lower case and control codes in its standard character set) is a better choice.

Extended Code 39 Characters

ASCII Value Character Extended Code 39
0 NUL %U
1 - 26 SOH - SUB $A - $Z
27 - 31 ESC - US %A - %E
32 SPACE SPACE
33 - 44 ! - , /A - /L
45 - -
46 . .
47 / /O
48 - 57 0 - 9 0 - 9
58 : /Z
59 - 63 ; - ? %F - %J
64 @ %V
65 - 90 A - Z A- Z
91 - 95 [ - _ %K - %O
96 ` %W
97 - 122 a - z +A - +Z
123 - 126 { - ~ %P - %S
127 DEL %T, %X, %Y, %Z