Code 39 is a variable-length symbology that can encode 44 characters. Code 39 is the most ubiquitous symbol in the non-retail world and is widely used in manufacturing, military and medical sectors. This code is also used by most car manufacturers as a code to mark the car model and its parts.

Code 39 barcodes can encode groups of uppercase letters (A-Z), numbers (0-9) and special characters. Each Code 39 barcode has a start/stop character represented by an asterisk (*). Barcode codes do not include check characters, but can be added programmatically. Each letter starts and stops with a "dark bar" consisting of 5 dark bars and 4 light bars. Narrow to wide bar ratios range from 2.2:1 to 3:1.

Perhaps the main drawback of Code 39 barcodes is their low data density. Although it requires more space than Code 128, Code 39 barcodes are still widely used and can be identified by any barcode scanner.

"Code39" barcode. "ABC-123" is the number encoded in the barcode.

Code 39 is an extended version of the Code 39 barcode that also supports the ASCII set of characters. The characters 0-9, AZ, “. Small Latin letters, additional punctuation marks, and control characters are represented as sequences of two Code 39 characters.

"Code39 Extended" barcode. "Abc+" is the number encoded in the barcode.