Code 39 is a popular non-retail symbology. It supports numbers, upper-case letters, and several special characters. Code 39 Extended supports all ASCII 128 characters by using double character encoding. For example, the lower-case letter "a" is represented by "+A". Because of the possibility of misrepresentation of a symbol, most bar code scanners must be switched to extended mode in order to recognize Code 39 Extended.

• The start and stop characters (represented by the asterisk character *) are added automatically if needed.
• To add asterisks around text, input the barcode with asterisks around the data. For example: *ABC* . Both *ABC* and ABC produce the same Code 39 barcode.
• The MOD 43 check character may be added to the bar code by setting the OptionalCheckChar property to Barcode_Only or Barcode_And_Text.
• In Code 39 Extended, control characters, such as TAB or NEW LINE, may be encoded by entering their three digit ASCII code prefixed by a caret (^). For instance, 1234^009 will encode 1234 followed by a tab character (ASCII 009).
• To encode the actual caret character: ^, escape it by entering it twice: ^^. For example, to encode ABC^DEF, enter: ABC^^DEF

• Symbology property