Understanding TLC-39 Barcodes: All You Need to Know

What are TLC 39 Barcodes

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With the constant advancement of technology, industries are continuously in search of efficient and accurate ways to encode and store data. The telecommunication industry, in particular, has become quite active in this regard and offers many solutions for encoding information.

One such barcode symbol that has been making waves in the telecommunication industry is the TLC39 code. Combining the power of Code 39 and the versatility of MicroPDF417, this composite barcode symbol has paved the way for data storage and encoding to new heights.

In this blog post, we will unravel the mystery behind the TLC39 barcode. We will take a closer look at its structure and advantages and provide an in-depth analysis of what makes it so important.

So, sit tight and join us on this informative journey as we delve into the world of TLC39 codes.

What is a TLC39 Code?- A Complete Overview

What are TLC 39 codes

The TLC39 code is also known as Telecommunications Industry Forum (TCIF) Code 39 and TCIF Linked Code 39. It is a composite barcode symbology introduced by Frederick Schuessler of Symbol Technologies, Inc. in 2001 and published by the Alliance for Telecommunications Industry Solutions (ATIS).

TLC39 facilitated the transition of companies from using linear code scanners to using more advanced equipment capable of reading both linear and two-dimensional (2-D) barcodes. 

TLC39 integrates two components: Code 39 and MicroPDF417 barcode.

Code 39 is a linear barcode symbology. It consists of a series of narrow and wide bars that represent the encoded data. On the other hand, the MicroPDF417 is a 2-D barcode symbology. It introduces a two-dimensional aspect to TLC39. 

To learn more about Code 39 barcodes, refer to our guide on what is Code 39 barcode.

TLC39 barcode is used to tag telecommunication equipment and manage telecommunications-related information. It can store data such as equipment details, manufacturer details, repair histories, service order details and other relevant data specific to telecommunication services. TLC39 has the ability to encode all 256 ASCII characters as well as 8-bit binary data.  

The TLC39 symbology is defined in US Patent Application Publication – US 2001/0045461 A1, which provides detailed information on its structure and usage.

What is the Purpose of the TLC39 Code?

The TLC39 code is specifically tailored for tagging telecommunication equipment. It enables efficient management of telecommunication devices by encoding relevant information such as equipment details, repair histories, and service order data.

TLC39 was widely utilised between 2000 and 2010, serving as a bridge between linear and two-dimensional barcode systems. However, since 2006, TLC39 has gradually transitioned to full 2D implementations, allowing for enhanced data capacity and more advanced barcode reading capabilities.

Two uses of TLC 39 codes

How to Recognise a TLC39 Code?

Two points on how to identify TLC39 barcodes

A TLC39 code can be recognised by visually observing its unique characteristics and components.

TLC39 combines a Code 39 barcode with a MicroPDF417 barcode. The Code 39 component is a regular linear component, while the MicroPDF417 is a 2-D barcode stacked component on top of it.

The Code 39 component is composed of a total of nine elements, with five bars and four spaces. Among these elements, three are wider bars, while the remaining six are narrower bars. 

On the other hand, the MicroPDF417 component can have varying sizes, ranging from 4 to 44 rows and 1 to 4 columns. MicroPDF417 barcodes encode data using codewords.

Codewords are groups of bars and spaces that represent numbers, letters, or symbols. Each codeword within the MicroPDF417 component is encoded using a set of four bars and four spaces, forming a pattern of 17 rectangular modules in a single row.

A key feature of TLC39 is the presence of a linkage flag, which appears as a set of five bars and four spaces arranged in a specific pattern. This pattern represents the letter “T” and is located to the right of the Code 39 symbol.

TLC39 omits the leading data identifier “S”, which is present in MicroPDF417 barcodes. Unlike some other composite barcode symbologies, TLC39 does not have a separator pattern between the Code 39 and MicroPDF417 components.

By recognising these distinctive features, one can successfully identify a TLC39 code.

Components of the TLC 39 Barcode

Two components of a TLC 39 Barcode

The TLC39 barcode is made up of two components.

  • Code 39
  • MicroPDF417

Code 39

Code 39 is a one-dimensional barcode symbology composed of a series of narrow and wide bars that represent the encoded information. The barcode can encode alphanumeric data, including uppercase letters, numbers, and a limited range of special characters.

The Code 39 component within a TLC39 barcode encodes the ECI number. Let us now understand what an ECI number is.

What is an ECI Number?

ECI stands for Equipment Category Item. It is a six-digit code used to retrieve the complete 10-character Common Language Equipment Identification (CLEI) code for the equipment.

The CLEI code is a unique identifier used globally to classify telecommunications equipment based on its features. It is obtained by manufacturers and assigned to devices before being sold to licensed service providers.

Before October 1, 2006, the ECI number was encoded in the TLC 39 symbol. However, since October 1, 2006, the full 10-character CLEI Code has been incorporated directly into the 2D product labels, rendering the ECI number unnecessary in the barcode.


MicroPDF417 is a compact two-dimensional stacked symbology that offers efficient data encoding in a limited space. It is based on the PDF417 barcode and inherits many of its features.

MicroPDF417 is not a variation of the PDF417 barcode symbology but rather a distinct symbology. It is commonly used in transportation, logistics, healthcare, and inventory management industries.

The TLC39 code uses the MicroPDF417 component to encode extra information. This component specifies the use of two required data elements.

  1. Product’s serial number
  2. Additional data elements

Product's Serial Number

The serial number refers to a unique identifier assigned to an item or equipment. It is an alphanumeric value that plays a crucial role in managing inventory and ensuring product authenticity.

The serial number within a TLC39 barcode follows specific formatting guidelines. It begins with a Data Identifier (DI) of ‘S’ or an Application Identifier (AI) of ‘8004’. These identifiers specify the type of data contained in the serial number.

The remaining characters in the serial number can vary in length but are limited to 25 characters. These characters can include uppercase letters, numbers, and, in some cases, special characters.

Additional Data

In a TLC39 barcode, additional data items can be included after the Serial Number to provide more detailed information about the encoded item or equipment. This additional data can include various details, such as the country of origin, manufacturing date, batch number, or other relevant information.

When adding additional data to the TLC39 code, it’s important to follow specific guidelines for the start character. 

If the serial number begins with a Data Identifier (DI), the DI should be added before any additional data. Similarly, if the serial number starts with an Application Identifier (AI), the AI should be added before including any supplementary information.

How to Get a TLC39 Code?

The TLC39 barcodes can be used without any restrictions as they are in the public domain. You can create them using tools like the TLC39 Code Generator or software like Seagull Scientific’s BarTender Software.

To obtain a TLC39 code, you can follow the step-by-step process outlined below.

  1. Determine the data to be encoded: Identify the information you want to encode in the TLC39 code.
  2. Format the data structure: Format the data according to the TLC39 specifications. This involves adding the necessary data identifiers and application identifiers and ensuring the correct length and format for each data element.
  3. Choose a barcode generation tool: Select a reliable tool or software that supports TLC39 encoding.
  4. Input the data: Enter the formatted data into the barcode generation tool. Provide the necessary details, such as the ECI number, Serial Number, or other required data elements.
  5. Generate the TLC39 code: Initiate the generation process within the chosen tool. The software will create the TLC39 barcode based on the provided data and specifications.
  6. Verify the barcode: Once the TLC39 code is generated, review it to ensure accuracy. Check that the encoded data matches your intended information.

Always test the readability of the TLC39 barcode using a barcode scanner. Verify that the encoded data can be accurately scanned and decoded.

There are various online options available for TLC code generation. Although free barcode generators are a cost-effective option, they do have certain limitations. These limitations include limited customisation options, no security features, and limited technical support.

To create accurate and top-notch barcodes, it is recommended to buy barcode generation software instead of using free ones. Paid software has advanced features, more customisable options, better technical support, and improved data-handling capabilities.

We highly encourage our clients to utilise Seagull Scientific’s BarTender Software, a prominent and industry-leading label creation and printing solution.

BarTender Software is the best solution for your label design, management, and printing requirements. It offers a wide range of features and an easy-to-use interface that enables you to create visually appealing labels that communicate your brand image effectively.

At Triton, we believe in providing tailored solutions that empower businesses to optimise their processes and achieve their desired outcomes. That’s why we offer a range of Seagull Scientific software editions so that you can choose the best for your needs and elevate your label printing experience to new heights.

Triton offers all four editions of BarTender software, namely, Starter Edition, Professional Edition, Automation Edition and Enterprise Edition. We also offer the latest member of the BarTender family, BarTender Cloud, which is a powerful cloud-based label printing solution.

If you want to know more about Seagull Scientific BarTender Software, you can either use the live chat widget below or fill out a form here.

How to Design TLC39 Barcodes?

To create a scannable barcode, it’s necessary to know the proper methods for designing barcode and label layouts. Our guides on best practices for designing labels and barcodes and common mistakes to avoid when designing barcodes will come in handy.

TLC39 code barcodes have specific requirements to be followed when designing them.

Code 39 Dimensions

Two points on width and X dimension of Code 39 barcodes

Barcode Width

Code 39 barcodes must have a narrowest bar that is at least 0.25 mm wide for accurate scanning.

To achieve the best readability, it is recommended to maintain a ratio of 2:1 between the width of the wider elements and the narrow elements within the barcode. However, a ratio of 3:1 is also considered acceptable. 

Barcode Height

A Code 39 barcode should have a minimum symbol height of 5 mm or 15% of its width, whichever is more as a recommended standard.

Point about code 39 barcode height

MicroPDF417 Dimensions

Two points on barcode height of MicroPDF417 barcode

Barcode Height

The dimensions of the MicroPDF417 symbol are determined by the amount of inputted data.

The height of the symbol can vary between 4 and 44 rows, and the row height can range from 1X to 10X, with “X” representing the X-dimension (width of the narrowest element of the barcode).

Barcode Width

The MicroPDF417 barcode can have a width between 40X and 101X, where “X” is the current X dimension.

Point on barcode width of MicroPDF417 barcode
Point about quiet zone of MicroPDF417 Barcode

Quiet Zone

A quiet zone refers to the clear space surrounding the barcode. 

For TLC39 barcodes, the quiet zone must be at least 1X wide on all four sides.

How to Print TLC39 Barcodes?

List of four points on printing rules of TLC39 Barcodes

For optimal readability and accurate scanning of TLC39 barcodes, it is important to follow the best practices for printing.

Here are some key printing guidelines to consider.

  1. Use High-Quality Printing Equipment: Invest in reliable, high-resolution printers that produce clear, sharp images.
  2. Maintain Contrast: Ensure sufficient contrast between the barcode and the background.
  3. Maintain Proper Quiet Zones: Adequate quiet zones allow scanners to identify the start and end of the barcode properly.
  4. Verify Barcode Quality: Regularly check the quality of printed barcodes to ensure they meet industry standards.

To print TLC39 barcodes, it is recommended to use a high-quality thermal printer.

Thermal printers are printing devices that utilise heat to create high-quality images on various print media. With their reliability, cost-effectiveness, and impressive print speeds, thermal printers have become a popular choice. The heat-based printing technology used by thermal printers ensures consistent and durable prints, making them a preferred option for various industries.

Please refer to our guide on how thermal printers work to gain a better understanding of the working of a thermal printer.

At the Triton Store, we take pride in offering a broad range of premium thermal printers from renowned brands such as Honeywell, Zebra, and TSC, as well as coloured label printers from OKI.

Our inventory is diverse and includes various printer models to accommodate an array of printing needs, such as direct thermal printers, thermal transfer printers, barcode label printers, desktop printers and industrial printers.

With our extensive selection, it’s effortless to identify the ideal solution that meets your specific needs. Whether you require dependable printing for small-scale tasks or robust performance for significant operations, we have the perfect thermal printer to suit your requirements.

So what are you waiting for? Browse our collection and explore the right thermal printer for your needs today. If you’ve any queries, feel free to contact us via the live chat widget below, and one of our experts will be happy to assist.


TLC39 codes have played a significant role in the telecommunications industry, offering a bridge between traditional linear barcodes and more advanced 2D barcode systems.

While TLC39 helped companies to transition from linear barcode scanners to more sophisticated equipment, its usage gradually declined because of its restrictions.

Since 2006, the telecommunications industry has shifted towards full 2D implementations, capitalising on their enhanced capabilities. Despite this, TLC39 codes continue to find utility in specific industrial applications. Their user-friendly nature and compatibility with various reading systems make them accessible to many users.

We hope this article has helped you to understand the TLC39 code bar code system in detail.

Thanks for reading!

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