Code 39 (also called Code 3 of 9) is one of the oldest and most versatile barcode symbologies. It can encode alphanumeric characters (A-Z, 0-9) and several special characters. Each character consists of 9 elements: 5 bars and 4 spaces, with 3 wide and 6 narrow elements.

Key Features

Character Set: 43 characters (A-Z, 0-9, space, -, ., $, /, +, %, *)
Density: Low to medium (about 9 elements per character)
Check Digit: Optional modulo 43 checksum
Applications: Inventory, ID cards, industrial labeling

Technical Specifications

Code 39 requires a quiet zone (10X) before and after the barcode. The asterisk (*) is used as start/stop character. While it has no formal length limit, practical scanners typically read up to 20-30 characters. Its main advantage is widespread scanner support, though its low density makes it unsuitable for small items.