Code 39

Code 39, also known as Code 3 of 9, is a variable-length discrete barcode symbology developed in 1974. It can encode 43 characters including uppercase letters (A-Z), digits (0-9), and special characters (space, $, %, +, -, ., /). Each character is represented by nine elements: five bars and four spaces, with three elements being wide.

Technical Standards: Code 39 is standardized under ANSI MH10.8M-1983, ANSI/AIM BC1/1995, and HIBC (Health Industry Bar Code). It offers excellent readability even when printed at low resolution, making it ideal for applications where printing quality may vary.

Advantages: Simple implementation, wide industry acceptance, excellent fault tolerance, and compatibility with most barcode scanners. The format's self-checking nature and ability to be read reliably even when damaged makes it particularly valuable in harsh industrial environments.