Code 39 Barcode Scanner

What is a Code 39 barcode?

Code 39 is a one-dimensional (1D) barcode symbology defined in ISO/IEC 16388:2007. Developed in 1974, it was among the first barcodes to support alphanumeric data, including letters, numbers, and some special characters. Each barcode includes start and stop characters (an asterisk *) that help barcode scanners identify the code’s boundaries. Additionally, Code 39 includes an optional check character or check digit for enhanced error detection.

Code 39 barcodes are easily scanned by most barcode scanners and support manual verification thanks to their text interpretation below the barcode.

Structure and components

Code 39 relies on patterns of wide and narrow bars and spaces to encode characters. Each character is represented by 9 elements—5 bars and 4 spaces. These include 3 wide and 6 narrow elements, creating the name “3 of 9.”

Code 39 barcodes consist of the following key components:

1. Quiet zones: Blank areas on both sides of the barcode that ensure proper scanning and readability.
2. Start character: An asterisk (*) that indicates the beginning of the barcode.
3. Data character: The main content section where information is encoded. Code 39 can encode 43 characters: numeric digits (0-9), uppercase letters (A-Z), seven special characters (-, ., $, /, +, %, and space).
4. Stop character: An asterisk (*) that indicates the end of the barcode.

Encoding and error detection

Code 39 uses a pattern of 5 bars and 4 spaces to represent each character. Out of those 9 positions, 3 are always wide (either bars or spaces), and 6 are narrow. Each character is assigned a numeric value, as shown in the table below.

These values are critical for calculating the checksum. This is an optional modulo 10 or 43 check character added to the end of the Code 39 barcode for enhanced error detection.

Here’s how the checksum is calculated:

1. Assign numeric values to each character in the data portion of the barcode (using the table).
2. Sum all those numeric values together.
3. Divide the sum by 43 (because there are 43 possible characters, 0-42).
4. The remainder of that division is the checksum value.
5. Look up the character corresponding to that checksum value in the table. This character is appended to the barcode as the checksum character.

Applications of Code 39 barcodes

Manufacturing and automotive

Code 39 is a preferred symbology in the automotive industry and factory automation for tracking components, products, and work-in-progress items. The Code 39 was standardized and adopted by the Automotive Industry Action Group and is now used as the standard VIN Barcode.

Healthcare

In the healthcare sector, Code 39 barcodes are crucial for patient identification, medication management, and equipment tracking. The Health Industry Bar Code Council (HIBCC) also uses them on wristbands, medication packaging, and medical devices.

Logistics

Code 39 barcodes are widely adopted for logistics applications, including inventory management, warehouse operations, and shipping processes.

Military and government

The United States Department of Defense uses Code 39 under the LOGMARS (Logistics Applications of Automated Marking and Reading Symbols) standard to label supplies and equipment.

Advantages of Code 39 barcodes

• Compact size: They store large amounts of data in a small space, making them suitable for use on compact or irregularly shaped surfaces.
• Error detection: Code 39’s self-checking structure and optional checksum enable basic error detection, but no error correction.
• Scalability: Code 39 offers flexibility with variable sizes, allowing for encoding of up to 43 characters, making it adaptable to different data capacity needs.
• Versatility: Omnidirectional scanning ensures seamless decoding from any angle.

Why choose the Scanbot SDK for Code 39 scanning?

The Scanbot Barcode Scanner SDK is specifically designed to handle the challenges of decoding Code 39 barcodes in real-world scenarios.

What sets us apart:

• Exceptional performance: Reliably decodes even damaged, low-contrast or distorted barcodes.
• High-speed scanning: Read Code 39 barcodes in as little as 0.04 seconds.
• Cross-platform compatibility: Easily integrate with Android, iOS, cross-platform, web, Windows, and Linux platforms.
• Customizable UI: Customize the ready-to-use components to match your app or website design.
• Privacy-first: Operates offline for complete data security.

Whether your use case involves Code 39 barcodes, QR codes, or any other barcode, the Scanbot SDK delivers the accuracy, speed, and reliability you need to succeed.

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