Code 3 of 9
Code 39 (Also Called Code 3 of 9) is suitable for encoding general purpose alphanumeric data. Reference symbology for many industry standards. Character encodation (standard and optional full ASCII), reference decode algorithm and optional check character calculation are included in this document. This specification is intended to be significantly identical to the corresponding Commission for European Normalization (CEN) specification.
Each bar code contains a start and stop character (*). Each character is composed of nine total elements 3 of which are wide elements and 6 are narrow.
Code 3 of 9 Characteristics
Encodable Character Set - All 36 Alphanumeric & 7 additional (- . SPACE $ / + %)
Code Type - Discrete
Elements per Symbol Character - 9 (5 bars & 4 spaces)
Modules per Symbol Character - 13 - 16
Representative Data Character Density - 6.25 CPI (based on X = 0.010 inch, N = 3:1)
Non-Data Overhead - Equivalent to 2 symbol characters
Character Self-Checking - Yes
Symbol Length - Variable
Symbol Check Character - One, Optional
Bidirectionally Decodable - Yes
Options - Full ASCII Mode Message Append
Quiet Zone - Equal to at least 10 x "X" dimension at the beginning and end of symbol
Symbol Height - At least .2 inch or 15 percent of symbol length, whichever is greater | 
