Code 128 Barcode Scanner

What is a Code 128?

Code 128 is a one-dimensional barcode format that encodes all 128 standard ASCII symbols, including uppercase and lower case letters, numeric digits, and special characters. It is defined in the ISO/IEC 15417:2007 standard and features three subsets (A, B, and C), each optimized for specific data types.

With its high density and flexibility, Code 128 can represent a large amount of information in a small space. It is ideal for logistics, warehousing, and other applications requiring compact and efficient barcodes.

Structure and components

Code 128 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: A unique 11-module pattern (3 bars and 3 spaces) that indicates which character set (A, B, or C) will be initially used.
3. Data character: The main content section where information is encoded. Each character consists of 11 modules (3 bars and 3 spaces). Code 128 encodes all 128 ASCII characters and automatically switches between sets A, B, and C for optimal efficiency.
4. Check character: A mandatory verification element calculated using a weighted modulo-103 checksum. It ensures data integrity by providing error detection.
5. Stop character: A distinct 13-module pattern (4 bars and 3 spaces) that marks the barcode’s end.

Code 128 consists of 108 symbols (103 data symbols, 3 start symbols, and 2 stop symbols) that shift between three character sets (A, B, and C) to encode data efficiently. Despite its name, it doesn’t contain 128 distinct symbols – instead, it achieves full ASCII coverage by switching between sets A and B, while set C specializes in encoding digit strings efficiently.

The table below shows what code set supports what characters:

Error detection

Code 128 uses mandatory error detection through a Modulo 103 check digit, but cannot correct errors. Here’s how it works:

1. A check digit is calculated from the encoded data
2. The scanner recalculates this digit during reading
3. If both check digits match, the data is considered valid
4. If they don’t match, the scan is rejected as an error

While Code 128 is effective at detecting errors, it does not have built-in error correction capabilities.

Applications of Code 128 barcodes

Logistics and shipping

These barcodes enable real-time package tracking and automated sorting in shipping operations across global supply chains.

Inventory management

These barcodes streamline inventory control by encoding comprehensive product data, including serial numbers, batch codes, and production dates.

Manufacturing

In production environments, Code 128 ensures accurate component tracking and assembly verification while maintaining complete product traceability.

Healthcare

Healthcare facilities rely on Code 128 for patient safety through precise tracking of medications, medical equipment, specimens, and patient records.

Advantages of Code 128 barcodes

• High data density: Encodes large amounts of information in a compact format.
• Full ASCII support: Represents standard ASCII symbols, including uppercase, lowercase, and special characters.
• Versatile encoding: Efficiently handles numeric, alphanumeric, and control codes through its three subsets.
• Standard printing: Barcodes can be created using regular printers, avoiding the need for specialized equipment.
• Durability: Reliable scanning of damaged barcodes ensures functionality in challenging conditions.

Why choose the Scanbot SDK for Code 128 barcode scanning?

The Scanbot Barcode Scanner SDK is tailored to decode Code 128 barcodes quickly and accurately, even in demanding scenarios.

What sets us apart:

• Exceptional performance: Reliably decodes even damaged, low-contrast or distorted barcodes.
• High-speed scanning: Reads Code 128 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 128, QR codes, or any other barcode, the Scanbot SDK delivers the accuracy, speed, and reliability you need to succeed.

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