Guide to Barcode Symbologies

Code 2-of-5, Interleaved (ITF / ITF-14)

 

Example of Code 2-of-5, Interleaved

Code 2-of-5, Interleaved

Interleaved 2-of-5 (often abbreviated as ITF) is a one-dimensional (1D) linear barcode symbology designed specifically for encoding numeric-only data. It is a variable-length barcode, but unlike many other symbologies, it must contain an even number of digits, as the data is encoded in pairs.

Interleaved 2-of-5 works by encoding information across both the bars and the spaces of the barcode, which allows it to achieve higher data density than standard Code 2-of-5 and several other early barcode formats. This makes it more space-efficient while remaining relatively easy to print and scan.

Barcode Density and Readability

While Interleaved 2-of-5 offers greater density than traditional Code 2-of-5, its overall density is still comparatively low when measured against newer barcode symbologies. However, this lower density is often considered an advantage rather than a drawback.

Because the bars and spaces are wider and more clearly defined, Interleaved 2-of-5 barcodes are easily read from a distance and perform well in demanding environments. They are also less vulnerable to minor damage, dirt, or print imperfections, making them well-suited to industrial and logistics applications.

Common Uses of Interleaved 2-of-5

Interleaved 2-of-5 is widely used in logistics and supply-chain environments, particularly where robustness and long-range scanning are required. Typical applications include:

  • Distribution centres and warehouses

  • Shipping and storage container labels

  • Pallet and carton identification

  • Logistics and transport systems

A well-known implementation of this symbology is ITF-14, which is commonly used to encode Global Trade Item Numbers (GTINs) on outer packaging and cartons.

Data Integrity and Check Digits

To improve data accuracy, Interleaved 2-of-5 supports an optional check digit, often referred to as a 10-character weighted module. This additional character helps verify the integrity of the scanned data and reduces the risk of errors during high-speed or automated scanning.

In environments where barcode data accuracy is critical—such as automated sorting systems or inventory tracking—the use of a check digit is strongly recommended.

Limitations and Considerations

Despite its strengths, Interleaved 2-of-5 is limited to numeric data only and requires an even number of characters, which can restrict its flexibility. For applications needing alphanumeric data or higher information density, alternative symbologies may be more appropriate.

However, when reliability, durability, and scan distance are key priorities, Interleaved 2-of-5 remains a trusted and widely supported barcode format.

Summary

Interleaved 2-of-5 is a durable, numeric barcode symbology commonly used in warehousing, distribution, and logistics. Its lower density improves scanning reliability and resistance to damage, making it ideal for industrial labelling and shipping environments where performance is more important than data complexity.