The Code 39 Full ASCII (sometimes also referred as Code 39 extended) is an extension to normal code 39. It is capable of encoding all 128 ASCII characters. It uses shift characters to combine two normal code 39 characters to encode a character not in the normal code 39 character set. The barcode generated is compatible with normal code 39, so a scanner must be configured to Full ASCII mode to read the barcode correctly.

Code 39 Full ASCII supports entering control characters using special character input method. You can use a back slash \ plus 3-digit decimal ASCII code to enter a control character. For example, the following input encodes digits 123, followed by a NUL character and letters abc:

Data Input: 123\000abc