Code 39

• Code 39 is also known as Alpha 39, Code 3 of 9, Code 3/9, Type 39, USS Code 39, or USD-3.
• Code 39 is a discrete, variable length symbology.
• It is self checking in that a single print defect cannot transpose one character into another valid character.
• The Code 39 specification defines 43 characters, consisting of uppercase letters (A through Z), numeric digits (0 through 9) and a number of special characters (-, ., $, /, +, %, and space).
• A special start/stop character (*) is placed at the beginning and end of each barcode.
• Code 39 does not require a checksum.

Structure of a Code 39 barcode

• A start character, the asterisk (*) character.
• Any number of characters encoded from the table below.
• An optional checksum digit calculated as described above and encoded from the table below.
• A stop character, which is a second asterisk character.

Advantages

• Wide use of this barcode type makes it portable.
• This barcode can be encoded and decoded by almost every barcode encoding/decoding equipment.
• Code 39 can encode all 26 capital Alphabets of the English language and the numerals which was not possible with the previous barcodes.
• It is much more secure and is not prone to faulty encoding and decoding.

Disadvantages

• 30% wider than Code 128.
• No error correction.
• without error correction you will get bad data.
• No lowercase characters supported by this.

Example

• Code 39 is widely used in many industries and is the standard for many government barcode specifications, including the U.S. Department of Defense.