Code 39 Barcode Scanner

What is a Code 39 barcode?

Code 39 is a one-dimensional (1D) barcode symbology standardized in ISO/IEC 16388. 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, corresponding to “3 of 9.”

The symbology can encode 43 characters: numeric digits (0-9), uppercase letters (A-Z), and seven special characters (-, ., $, /, +, %, and space).

Code 39 barcodes consist of the following key components:

1. Quiet zones: Blank areas on both sides of the barcode that ensure proper detection and readability.
2. Start character: An asterisk (*) that indicates the beginning of the barcode.
3. Data characters: The main content section where information is encoded.
4. Stop character: An asterisk (*) that indicates the end of the barcode.

Encoding and error detection

Each character pattern is assigned a numeric value, as shown in the table below.

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

Here’s how the checksum is calculated and encoded:

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 (the number of possible values) or 10.
4. The remainder of that division is the checksum value.
5. The character corresponding to this value is appended to the barcode.

Applications of Code 39 barcodes

Manufacturing and automotive

Code 39 is common in the automotive industry and factory automation for tracking components, products, and work-in-progress items. It was also adopted by the Automotive Industry Action Group as the standard VIN Barcode.

Healthcare

In the healthcare sector, Code 39 barcodes are used for patient identification, medication management, and equipment tracking. In particular, the Health Industry Bar Code Council (HIBCC) regulates their use on wristbands, medication packaging, and medical devices.

Logistics

Code 39 barcodes are widespread in 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

• Ease of printing: Code 39 uses only two different bar widths (wide and narrow), making it highly lenient for printing on various surfaces.
• Error detection: Code 39’s self-checking and optional checksum enable basic error detection, but no error correction.
• Scalability: Code 39 can hold alphanumeric data and has no length limit, making it useful for a variety of applications.
• Omnidirectional scanning: The asymmetric start and stop character 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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