Chapter 50: Integration in Logistics - The Dual-Label |
Synopsis |
Modern logistics has evolved beyond single-technology tracking. The dual-label approach---combining a barcode (such as GS1-128 or Data Matrix) with an RFID inlay on a single shipping label---represents the current state of the art in supply chain visibility. This chapter examines the practical implementation of dual-label systems across multiple industries, exploring how the complementary strengths of optical and radio-frequency identification create resilience, efficiency, and redundancy. We also examine the technical characteristics of Code 39, a foundational barcode symbology, and analyze how its specific properties have influenced its adoption patterns across different sectors. From fashion retail to pharmaceutical distribution, from returnable transport item pooling to automated warehouse validation, the dual-label has become the standard for organizations that cannot afford tracking failures. |
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1. Introduction: The Case for Redundancy |
Imagine a warehouse receiving a thousand pallets per hour. Each pallet must be identified, routed, and logged within seconds. Now imagine that a single barcode is smudged, or an RFID tag is shielded by metal packaging. The entire flow could stall. This is the reality of modern logistics, where failure is not an option and redundancy is not a luxury but a necessity. |
The dual-label approach addresses this challenge by providing two independent data carriers on the same physical label. The barcode---typically a GS1-128 linear symbology or a Data Matrix 2D code---serves as the primary optical identifier, readable by handheld scanners and vision systems. The RFID inlay, usually a UHF RAIN RFID tag compliant with GS1 EPC standards, provides the radio-frequency channel for bulk, non-line-of-sight reading . |
This chapter explores how this combination has transformed logistics operations, creating systems that are simultaneously faster, more reliable, and more flexible than any single-technology solution. |
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2. The Anatomy of a Dual-Label |
A dual-label is more than just two technologies on one piece of adhesive paper. It represents a carefully engineered system where each component compensates for the other's limitations. |
2.1 The Optical Component: GS1-128 and Data Matrix |
The barcode element of a dual-label is typically a GS1-128 symbology. Unlike simpler barcodes, GS1-128 encodes Application Identifiers (AIs) that give context to the data. An AI of (01) indicates a Global Trade Item Number (GTIN), while (17) denotes an expiration date, (10) a batch or lot number, and (00) a Serial Shipping Container Code (SSCC) . This structured data format allows logistics systems to instantly understand what each scanned number represents, eliminating the ambiguity that plagues simpler encoding schemes. |
For smaller items or applications requiring greater data density, the dual-label may instead use a GS1 DataMatrix 2D code. This symbology packs significant information into a compact square pattern and is mandatory for pharmaceutical serialization in many jurisdictions . The DataMatrix code can encode the same GS1 element strings as GS1-128 but in a fraction of the space, making it suitable for item-level marking where label real estate is limited. |
2.2 The Radio Component: RFID Inlays |
The RFID element of a dual-label is typically a passive UHF tag operating in the 860-960 MHz band. These tags have no internal battery; they harvest energy from the reader's interrogation signal to power their microchip and transmit back a response. The tag memory contains an Electronic Product Code (EPC), a standardized identifier that typically includes a GTIN and a unique serial number . |
The dual-label's RFID inlay is not merely an alternative identifier but a complementary one. While the barcode requires line-of-sight and proximity to be read, the RFID tag can be interrogated from several meters away, through packaging materials, and in bulk. A single RFID reader can capture the identities of hundreds of tagged items simultaneously, a capability that transforms warehouse operations . |
2.3 Information Redundancy and Consistency |
In a properly designed dual-label system, the barcode and RFID tag encode the same core identifier---typically the GTIN and serial number---ensuring that regardless of which technology is used, the item's identity remains unambiguous. This redundancy means that if one carrier is damaged, unreadable, or fails, the other can still provide the necessary identification. |
The dual-label approach also supports what might be called 'operational redundancy.' Warehouse processes can be designed to use RFID for high-speed automated reads at portals and tunnels, while relying on barcodes for manual interventions, exception handling, and verification . This hybrid workflow maximizes efficiency without sacrificing resilience. |
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3. The Technical Foundation: How RFID Complements Barcodes |
To understand the value of the dual-label, one must appreciate the fundamental differences between optical and radio-frequency identification. These differences are not merely technical curiosities but operational characteristics that determine when and where each technology excels. |
3.1 Line-of-Sight vs. Non-Line-of-Sight |
Barcodes require a direct optical path between the scanner and the label. If the label is obscured, damaged, or oriented away from the reader, scanning fails. This limitation is why forklift drivers must position pallets carefully when passing through barcode portals, and why warehouse workers must rotate items to find the label during manual scanning. |
RFID, by contrast, does not require line-of-sight. Radio waves penetrate cardboard, plastic, and many other materials, allowing tags to be read even when hidden inside cartons or oriented arbitrarily. This characteristic enables bulk reading, where an entire pallet load of tagged items can be identified without unpacking or repositioning . |
3.2 Serialized Reading vs. Bulk Reading |
A barcode scanner reads one code at a time. Even with high-speed imagers, each code must be individually framed and decoded. This makes barcode-based sorting and verification inherently sequential, creating a bottleneck in high-throughput operations. |
RFID readers, however, can interrogate and receive responses from many tags nearly simultaneously. A well-tuned RFID portal can read hundreds of tags per second, processing an entire carton's contents in the time it takes to scan a single barcode . This capability is the foundation of RFID tunnels, where boxes speed along conveyors while the system automatically validates their contents. |
3.3 The Economics of Integration |
RFID tags are more expensive than printed barcodes---typically costing several cents each compared to fractions of a cent for printed labels. This cost differential has historically limited RFID adoption to high-value items or applications where the operational benefits justify the expense. |
The dual-label approach provides a pragmatic middle ground. By combining a low-cost barcode with a more expensive RFID tag, organizations can implement automated reading where it provides the greatest benefit while retaining barcode-based manual processes for lower-value or lower-volume operations. The barcode also serves as a backup when RFID fails or when dealing with partners who have not yet adopted RFID . |
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4. The Persistent Relevance of Code 39 |
Before exploring industry applications in depth, it is worth examining one of the oldest and most influential barcode symbologies: Code 39. Despite the proliferation of more advanced symbologies, Code 39 remains in widespread use across multiple industries, and understanding its technical characteristics illuminates why certain applications continue to rely on specific barcode technologies. |
4.1 Technical Characteristics of Code 39 |
Code 39, introduced in 1974 by Intermec Corporation, was the first barcode specification that could encode both numeric digits and alphabetic characters . Each character in Code 39 is encoded using a pattern of five bars and four spaces, with exactly three of these nine elements being wide and the remaining six narrow---hence the name 'Code 3 of 9' . |
The symbology's character set includes 43 symbols: uppercase letters A-Z, digits 0-9, and seven special characters (space, period, dash, slash, percent, plus, and dollar). The asterisk is reserved as the start and stop character. Code 39 Extended (Full ASCII) can represent all 128 ASCII characters by encoding characters as pairs of base symbols, though this doubles the symbol width for extended characters . |
4.2 The Self-Checking Property |
One of Code 39's most important technical features is its self-checking property. Because each character has a distinct pattern of wide and narrow elements, a single printing defect cannot transform one valid character into another. If a bar width error occurs, the resulting pattern is invalid, which the decoder can detect and reject . |
This self-checking capability means that Code 39 does not require an obligatory checksum character, although many applications add a Modulo 43 check digit for additional security . In practice, specifications such as MIL-STD-130 for U.S. military marking mandate the use of check digits to ensure data integrity . |
4.3 Data Density and Space Constraints |
Code 39's primary limitation is its relatively low data density. The symbology requires significant space for each encoded character, with a typical capacity of 20 to 23 alphanumeric characters before the label becomes impractically large . A ten-character Code 39 barcode is approximately 40% wider than the equivalent Code 128 barcode . |
This low density makes Code 39 unsuitable for applications with severe space constraints, such as small product labels or pharmaceutical packaging where real estate is at a premium. For such applications, more dense symbologies like Code 128 or Data Matrix have largely replaced Code 39. |
4.4 Scanner Compatibility and Infrastructure |
Code 39's enduring strength is its near-universal scanner compatibility. Because it has been in use for five decades, virtually every barcode scanner on the market can read Code 39 symbols without special configuration . This compatibility has created a massive installed base of Code 39-capable equipment that would be expensive and disruptive to replace. |
This infrastructure inertia explains why Code 39 persists in applications where changing symbologies would require costly upgrades across an entire supply chain. Even when new symbologies offer technical advantages, the cost of retooling existing systems often outweighs the benefits. |
4.5 Influence on Industry Adoption Patterns |
The technical characteristics of Code 39 have shaped its adoption across industries in predictable ways. The self-checking property, combined with alphanumeric encoding, made it attractive for applications where data accuracy and human-readable content were paramount. The low data density, however, pushed it toward applications where the data requirements were modest and label space was generous. |
These factors explain Code 39's stronghold in U.S. military logistics (LOGMARS), automotive parts labeling (AIAG), and healthcare identification (HIBC), where established specifications have standardized on the symbology and significant infrastructure investments lock in its continued use . Conversely, Code 39 has been largely replaced by Code 128 in retail and consumer goods, where higher density and more efficient encoding provide clear advantages. |
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5. Application: Fashion Retail and Distribution |
The fashion industry has been among the most aggressive adopters of dual-label technology, driven by the high value of inventory, the seasonal nature of collections, and the stringent compliance requirements of major retailers. |
5.1 Item-Level Serialization and Vendor Compliance |
Global fashion retailers increasingly mandate that suppliers tag individual items with RFID labels at the point of manufacture. These mandates require suppliers to print and apply EPC-compliant RFID tags to each garment, often in conjunction with a printed barcode that serves as a backup identifier . |
Consider the case of a fishing hook manufacturer supplying major international retailers. Facing a customer mandate for item-level RFID tagging, the company implemented an RFID vendor tagging solution that prints and encodes EPC-compliant labels on-site. Operators scan a barcode to trigger RFID label printing, with each label encoded with a unique serial number managed securely in the cloud . This approach ensures full traceability from production to sale while meeting retailer compliance requirements. |
The dual-label approach is essential here because the barcode provides a fallback mechanism that the retailer's distribution centers can use if RFID reads fail. It also enables manual checks and cycle counting using handheld scanners, maintaining operational flexibility even in automated facilities. |
5.2 Automated Order Validation with RFID Tunnels |
At the distribution center level, dual-label technology enables sophisticated automated validation systems. One North American fashion group implemented high-density RFID tunnels fully integrated into conveyor lines to automatically validate the contents of each open box after picking . |
The system combines RFID tunnels capable of processing up to 1,000 boxes per hour and reading up to 600 items per box, with barcode readers for box identification. As each box passes through the tunnel, the system reads every RFID tag inside, compares the detected items against the expected order data, and automatically rejects non-compliant shipments . |
The impact has been significant. The fashion group achieved a 17% reduction in discrepancies detected after the RFID tunnels, along with a substantial decrease in non-compliant shipments reaching customers. This reduction in errors translates directly into savings in chargeback penalties---which in U.S. fashion retail can reach up to 20% of invoice value---and improved product availability at stores . |
The barcode readers in this system serve a critical role: they identify the box itself, telling the system which order to validate against. This combination of barcode-based box identification and RFID-based content validation creates a system that is more robust than either technology alone. |
5.3 The Code 39 Connection in Fashion |
While fashion logistics increasingly relies on GS1-128 and Data Matrix barcodes for GS1 compliance, Code 39 remains relevant in certain fashion supply chain applications. Inventory management systems for high-volume, low-cost items often use Code 39 on internal warehouse labels because of its compatibility with existing scanners. The self-checking property provides assurance that inventory counts are accurate, while the ability to encode alphanumeric identifiers allows for human-readable data alongside the barcode. |
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6. Application: Pharmaceutical and Healthcare Logistics |
The pharmaceutical industry faces some of the most stringent tracking requirements of any sector. Regulatory mandates for serialization, combined with the need for cold chain monitoring and recall readiness, have driven widespread adoption of dual-label technology. |
6.1 Regulatory Compliance and Serialization |
In many jurisdictions, pharmaceutical products must carry a unique serial number that can be traced from manufacturer to patient. Saudi Arabia's SFDA, for example, mandates GS1 DataMatrix codes on drug packaging, encoding the GTIN, serial number, batch, and expiry date . This requirement enables full drug traceability and facilitates recalls when necessary. |
The dual-label approach in pharmaceutical logistics typically involves a DataMatrix barcode printed directly on the packaging and an RFID tag applied to the shipping carton or pallet. The barcode provides the required regulatory compliance and enables pharmacy-level scanning, while the RFID tag enables automated handling throughout the distribution chain. |
6.2 Cold Chain Monitoring and Real-Time Visibility |
For temperature-sensitive pharmaceuticals, RFID tags can incorporate temperature sensors that record thermal history throughout the supply chain. When combined with a barcode identifier, these smart tags provide both identity and condition monitoring in a single integrated label. |
The barcode serves as a simple, low-cost identifier that can be scanned at any point without specialized equipment. The RFID tag provides the capability for automated reads at warehouse portals and integration with temperature monitoring systems. If the RFID tag fails, the barcode still provides the product identity, allowing manual intervention to retrieve temperature data from alternative sources or log the product's handling history. |
6.3 Healthcare Supply Chain Applications |
Beyond pharmaceuticals, healthcare logistics has embraced dual-label technology for medical devices, supplies, and equipment tracking. The Healthcare Industry Bar Code (HIBC) standard, which builds on Code 39, has been a cornerstone of healthcare identification for decades . The self-checking property of Code 39 is particularly valuable in healthcare, where misidentification can have serious consequences for patient safety. |
Hospitals increasingly use RFID for asset tracking of expensive equipment, while relying on barcodes for consumable items. The dual-label approach allows a single label to serve both purposes, with the barcode providing immediate visual identification and the RFID tag enabling automated inventory tracking as equipment moves through the facility. |
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7. Application: Returnable Transport Item (RTI) Pooling |
Returnable transport items---pallets, crates, totes, and containers that circulate between supply chain partners---represent one of the most challenging logistics applications. These items must be tracked across multiple organizations, through diverse environments, and over extended periods. The dual-label has proven essential for effective RTI management. |
7.1 The Challenge of Tracking Circulating Assets |
A logistics provider managing a pool of over 90,000 returnable transport items faced significant challenges with traditional tracking methods. Manual logging lacked transparency, leading to substantial expenses from lost or unreturned containers, costly safety stock, and production downtime . The core problem was the inability to efficiently track RTIs in bulk---a limitation that manual barcode identification could not overcome. |
The solution was a hybrid system that equipped each RTI with a label combining both barcode and UHF RFID tags, ensuring universal identification regardless of the technology used. RFID gates were deployed at all loading bays, where forklift trucks drive stacks of boxes through for automatic identification. Up to 20 compactly stacked boxes can be simultaneously recorded with one forklift load . |
7.2 The Hybrid Identification Model |
The dual-label approach in RTI tracking serves multiple purposes. The barcode provides a low-cost, universally readable identifier that any partner can scan, regardless of whether they have adopted RFID. The RFID tag enables automated bulk reading at the logistics provider's own facilities, dramatically reducing the time and labor required for inventory management. |
This hybrid model also supports what might be called 'progressive adoption.' Partners who are not yet RFID-capable can still participate in the tracking system by scanning barcodes. As partners invest in RFID equipment, they can gradually transition to the more automated approach without requiring changes to the labeled assets . |
7.3 Real-Time Visibility and Demand Forecasting |
The data captured through dual-label tracking provides more than just asset location. The logistics provider uses real-time visibility into RTI location and status to forecast customer demand, proactively managing stock to ensure timely availability, especially during peak seasons . This predictive capability is only possible because the tracking system provides consistent, accurate data across the entire asset pool. |
The barcode component of each dual-label ensures that even if the RFID tag is damaged or malfunctioning, the item can still be identified and tracked. In the harsh environments typical of industrial RTI applications, this redundancy is essential for maintaining tracking continuity. |
7.4 Code 39 in RTI Applications |
The RTI pooling application often uses Code 39 barcodes on asset tags because of the symbology's durability and self-checking properties. Code 39 labels can be printed on rugged materials that withstand repeated handling, exposure to weather, and abrasion. The self-checking property ensures that wear and damage to the printed symbol does not result in misidentification. |
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8. Application: Automated Warehouse and Sortation Systems |
Modern warehouses are increasingly automated, with conveyor systems, robotic pickers, and automated storage and retrieval systems (AS/RS). These automated environments place unique demands on identification systems, making the dual-label approach particularly valuable. |
8.1 The Dual-Label in Warehouse Automation |
Research on automated warehouse scheduling systems has proposed a double-label management mode based on the combination of RFID tags and barcodes. This approach realizes the binding of information throughout the warehouse logistics process, enabling convenient transmission and traceability between upstream and downstream departments . |
In this model, the RFID tag provides the high-speed, non-line-of-sight identification needed for automated sorting and routing. The barcode provides a visual backup that can be scanned by operators during exception handling and manual interventions. The combination creates a system that is simultaneously highly automated and operationally resilient. |
8.2 Sortation and the Two-Sided Label |
One practical innovation in warehouse automation is the dual-sided label, where two identical barcodes are printed and applied to different faces of a carton. This approach addresses the problem of orientation dependency: a carton on a conveyor may be oriented such that its label is not visible to fixed scanners . |
The dual-label print-and-apply machine prints two identical labels in one process, applying them to both the front and side of the carton. This creates full barcode visibility regardless of orientation, optimizing sortation efficiency. With labels on two visible sides, scanners can easily read barcodes in automated sorting zones, reducing delays caused by blocked or hidden labels . |
When combined with RFID, this optical redundancy creates an exceptionally robust tracking system. The RFID tag provides bulk reading capability, while the multiple barcodes ensure that even if the RFID fails or is shielded, the carton can still be identified and sorted optically. |
8.3 Pick-to-Light and Verification Systems |
Software systems for warehouse management increasingly integrate barcode and RFID operations. Pick-to-light systems, where bin lights illuminate to guide pickers to the correct location, can be triggered by scanning a product barcode or by RFID reads. Cycle counting applications can use both technologies, with RFID enabling bulk counts and barcodes providing individual item verification . |
The dual-label approach is particularly valuable for put-away and pack verification. In these processes, workers scan destination location barcodes and compare them against system-suggested placements. The RFID component confirms that the correct items have been placed in the correct location, creating a closed-loop verification system . |
8.4 Code 39 in Warehouse Applications |
Code 39 continues to appear in warehouse applications where legacy systems and equipment remain in service. Many warehouse management systems still use Code 39 for location labels, bin labels, and pick labels because of the symbology's compatibility with existing scanners and printers. The self-checking property is particularly valuable on location labels, where misreading a bin label could send a picker to the wrong location, causing picking errors and inventory inaccuracies. |
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9. Application: Automotive and Manufacturing Logistics |
The automotive industry, with its just-in-time supply chains and complex supplier networks, has been an early and consistent adopter of automatic identification technologies. Dual-label approaches are now common throughout automotive logistics. |
9.1 The Automotive Industry Action Group (AIAG) Standard |
The Automotive Industry Action Group (AIAG) has long specified barcode labeling standards for automotive parts. These standards originally called for Code 39 labels on parts and shipping containers, and the AIAG B-1 standard remains a reference for automotive barcode labeling . |
The dual-label approach in automotive logistics typically involves a GS1-128 barcode for shipping container labeling, supplemented by an RFID tag for automated tracking through the supply chain. This combination allows suppliers to meet AIAG labeling requirements while enabling the automated receiving and sortation that modern automotive plants require. |
9.2 Just-in-Time Supply Chain Requirements |
Automotive manufacturing operates on just-in-time principles, where parts arrive at the assembly plant precisely when needed. Any delay or error in identification can cause line stoppages, costing thousands of dollars per minute. This sensitivity to identification errors has driven the adoption of dual-label systems with multiple layers of redundancy. |
The barcode component provides the primary identifier for supplier labeling and manual verification. The RFID component enables automated receiving at the plant dock, where parts are quickly read as they enter the facility. The combination ensures that even if the RFID system experiences interference or technical issues, the receiving process can continue using barcode scanning. |
9.3 Assembly Tracking and Work-in-Process |
Beyond logistics, dual-label technology is used for tracking work-in-process through manufacturing. Parts and assemblies carry barcodes and RFID tags through production steps, allowing the system to track their progress, verify that required operations have been completed, and maintain full traceability. |
The barcode is typically used for manual scanning at workstations where operators record their work. The RFID tag enables automated reading as assemblies pass through portals or past fixed readers, creating a comprehensive record of the production process without requiring operator action. |
9.4 Code 39 in Automotive Applications |
Code 39 remains prevalent in automotive logistics because of the industry's long history with the symbology. The AIAG B-1 standard established Code 39 as a requirement for part labeling, and many automotive suppliers continue to use the symbology because changing would require retooling across the entire supply chain . |
The self-checking property of Code 39 is particularly valuable in automotive applications, where parts may be handled roughly and labels may become damaged or obscured. The self-checking characteristic ensures that a damaged label will be rejected rather than misread, preventing misidentification that could cause assembly errors. |
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10. Application: Defense and Government Logistics |
The U.S. Department of Defense has been a major driver of barcode technology adoption, and defense logistics continues to be an important application area for dual-label systems. |
10.1 The LOGMARS Legacy |
The LOGMARS (Logistics Applications of Automated Marking and Reading Symbols) system, developed by the U.S. military, was one of the first large-scale barcode implementations. LOGMARS specified Code 39 labels for all government property marking, creating a standard that persisted for decades . |
MIL-STD-130, the military standard for identification marking of U.S. government property, continues to specify Code 39 as a permitted symbology, though it has been updated to include Data Matrix and other 2D codes for items with space constraints. The standard includes checksum requirements, often mandating Modulo 43 check digits for enhanced data integrity . |
10.2 Defense Supply Chain Modernization |
Modern defense logistics has embraced dual-label technology, with RFID supplementing traditional barcode marking on many items. The U.S. Department of Defense has mandated RFID tagging for certain categories of supplies, creating a hybrid environment where barcodes and RFID coexist. |
The dual-label approach is particularly valuable in defense logistics for several reasons. The barcode provides a simple, low-cost identifier that can be read with existing equipment at any facility. The RFID tag enables automated tracking through the supply chain, improving visibility and reducing the labor required for inventory management. |
10.3 Sustaining Legacy Systems |
The defense sector's reliance on Code 39 is a classic example of infrastructure inertia. Billions of dollars have been invested in LOGMARS-compatible equipment, training, and processes. The cost of transitioning to newer symbologies across the entire defense supply chain would be enormous, and the operational disruption would be significant. |
This means that Code 39 will remain in defense logistics for years to come, even as new implementations increasingly use GS1-128 and Data Matrix for their higher density and richer data content. The dual-label approach allows defense logistics to accommodate this transition: new labels can incorporate both modern symbologies and legacy Code 39 codes, ensuring compatibility with both new and old reading equipment. |
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11. Application: Third-Party Logistics (3PL) Providers |
Third-party logistics providers handle goods for diverse customers with varied requirements. This diversity creates a unique challenge: a single 3PL facility must be able to read and process labels from multiple source systems, with different symbologies, data structures, and technologies. |
11.1 The Problem of Customer Diversity |
A 3PL provider may handle apparel for one customer, automotive parts for another, and consumer electronics for a third. Each customer may have different labeling requirements, different systems integration needs, and different levels of technology adoption. The 3PL must accommodate all of these without maintaining entirely separate operational processes. |
The dual-label approach provides a pragmatic solution. By supporting both barcode and RFID, the 3PL can read customer labels regardless of the technology used. If a customer uses RFID, the automated receiving process can leverage bulk reading capability. If a customer uses barcodes only, the provider can still receive and process goods using handheld scanners. |
11.2 System Integration and Interoperability |
Modern 3PL operations rely on warehouse management systems that must integrate with customer systems. These integrations typically use GS1 standards for data exchange, with GS1-128 barcodes and EPC-compliant RFID tags providing the common data language . |
The dual-label supports interoperability by ensuring that the same information is available in both optical and radio-frequency formats. If a customer system expects RFID data, the label provides it. If a customer system requires barcode data, the label also provides that. The dual-label thus becomes a bridge between different technical capabilities and operational preferences. |
11.3 Supporting Mixed Technology Adoption |
Not all 3PL customers have adopted RFID, and even those who have may have different levels of implementation. Some may only use RFID for certain product categories, while others may use it across their entire supply chain. |
The dual-label approach supports this mixed adoption by allowing customers to transition to RFID at their own pace. Customers who are not yet RFID-capable can continue scanning barcodes. As they invest in RFID equipment, they can begin using the RFID capabilities of the same labels. The 3PL does not need to maintain separate label inventories or specialized handling procedures for RFID and non-RFID customers. |
11.4 Code 39 in 3PL Operations |
Many 3PL providers operate legacy systems that were designed around Code 39 barcodes. These systems may have been in place for years or decades, and replacing them would be costly and disruptive. The continued use of Code 39 in these facilities is driven by the same infrastructure inertia that keeps it alive elsewhere. |
For 3PL providers, the challenge is to maintain compatibility with legacy systems while transitioning to newer technologies. The dual-label approach can help, with newer labels encoding data in both Code 39 (for legacy scanners) and GS1-128 or Data Matrix (for modern systems). This gradual transition supports the shift to more efficient symbologies without stranding existing equipment. |
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12. Implementation Challenges and Best Practices |
Deploying a dual-label system is not without challenges. Organizations must navigate technical, operational, and organizational issues to achieve the full benefits of the approach. |
12.1 Label Design and Layout |
The dual-label's physical design is critical to its effectiveness. The barcode and RFID inlay must be positioned so that one does not interfere with the other. The RFID inlay should not cover the barcode, and the barcode should not contain materials that could shield the RFID tag from radio-frequency signals. |
The label must also accommodate the requirements of both reading systems. The barcode needs sufficient quiet zones (blank space) around it to be decoded reliably. The RFID inlay needs to be positioned so that it can be read consistently when the labeled item passes through RFID portals . |
12.2 Print and Encode Quality |
Dual-labels are typically produced using specialized printers that can print the barcode and encode the RFID tag in a single pass. This requires printers and supplies that have been qualified for the specific label material and encoding requirements. |
Print quality affects both the barcode and RFID components. Poor print quality can make the barcode unreadable, while mis-encoding the RFID tag can make it unrecognizable. Organizations should implement quality control processes to verify both the printed barcode and the encoded RFID data on each label . |
12.3 Environmental and Interference Issues |
RFID tags can be affected by their environment. Metal objects and liquids can reflect or absorb radio-frequency signals, making RFID tags difficult to read. The presence of multiple tags in close proximity can cause signal interference, reducing read reliability . |
Organizations deploying dual-label systems should test their RFID operation in the actual conditions where the labels will be used. Extensive testing and system design are often required to achieve optimal read results, especially in dense product environments or with challenging materials . |
12.4 Data Synchronization |
In a dual-label system, the data encoded in the barcode and RFID tag must be synchronized. If the barcode says one thing and the RFID tag says another, confusion and errors result. Organizations should implement processes to ensure that the same identifier and data are encoded in both carriers, and that any updates or corrections are applied to both. |
Software systems must also be designed to handle the dual-label approach properly. When a barcode and RFID tag provide conflicting information, the system should have rules for determining which data to trust, or for flagging the inconsistency for human investigation. |
12.5 Cost Considerations |
RFID tags are more expensive than printed barcodes, and the equipment for printing and encoding RFID labels is also more costly. Organizations must carefully evaluate the return on investment for RFID adoption, considering the operational benefits against the higher cost. |
The dual-label approach allows organizations to deploy RFID gradually, starting with high-value items or high-throughput operations where the technology provides the greatest benefit. The barcode component ensures that all items remain identifiable even if the organization is not yet using RFID for all categories. |
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13. Future Trends: Beyond the Dual-Label |
The dual-label approach represents the current state of the art in logistics identification, but the technology continues to evolve. New developments promise to further enhance the capabilities and reduce the limitations of current systems. |
13.1 Connected Packaging |
Connected packaging refers to packaging that incorporates advanced technologies like RFID, Bluetooth Low Energy (BLE), Near Field Communication (NFC), and serialized QR codes to create a digital identity for products . This approach goes beyond simple identification, enabling real-time tracking, improved inventory visibility, and communication with consumers. |
For a quick-service restaurant chain tracking fresh beef throughout its supply chain, connected packaging using RFID technology enables precise, scalable solutions for transitioning from frozen to fresh beef---essential for maintaining quality and meeting demand . The dual-label approach provides a foundation for these more sophisticated connected packaging applications. |
13.2 Digital Twins and Traceability |
The combination of barcodes and RFID, integrated with data sharing standards like EPCIS (Electronic Product Information Service), enables the creation of digital twins---virtual representations of physical items that capture their complete history, including location, condition, and handling . |
The dual-label provides the persistent identity that anchors the digital twin. Whether scanned by barcode or RFID, the item's identity is consistently recognized, allowing the accumulation of data from multiple sources across the supply chain. |
13.3 Artificial Intelligence and Machine Vision |
Advances in machine vision and artificial intelligence are expanding the capabilities of optical identification. AI-powered vision systems can read barcodes under challenging conditions, including damaged labels, poor lighting, and unusual orientations. These systems can also recognize items by visual features even when labels are missing or unreadable. |
The dual-label approach can incorporate these advances by providing both the traditional optical marker (the barcode) and the tag for AI-assisted identification. The combination creates systems that are more robust and capable than either technology alone. |
13.4 Sustainability Considerations |
The environmental impact of labeling is receiving increasing attention. RFID tags contain electronic components, raising concerns about electronic waste and the sustainability of widespread adoption. Barcode labels are generally more environmentally benign but may require frequent replacement and generate significant waste in high-volume operations. |
The dual-label approach may need to evolve to address these sustainability concerns. Future systems might incorporate recyclable RFID tags, biodegradable label materials, and designs that reduce material usage while maintaining functionality. |
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14. Conclusion: The Resilience of Redundancy |
The dual-label approach represents a pragmatic response to the challenges of modern logistics. By combining the complementary capabilities of barcodes and RFID, organizations can achieve levels of efficiency, accuracy, and resilience that neither technology could provide alone. |
The barcode provides universal readability, low cost, and compatibility with legacy systems. The RFID provides bulk reading, non-line-of-sight capability, and automation potential. Together, they create systems that are faster, more reliable, and more flexible than any single-technology alternative. |
The persistence of Code 39 in many applications illustrates a broader principle: technology adoption is not solely determined by technical superiority but by the interplay of technical characteristics, installed base, and organizational inertia. Code 39's self-checking property, alphanumeric capacity, and scanner compatibility have kept it relevant even as more advanced symbologies have been introduced. Its role in military, automotive, and healthcare applications shows how technical characteristics can become embedded in industry standards and supply chain infrastructures. |
As logistics systems continue to evolve, the dual-label approach will likely remain relevant. New technologies will emerge, and the balance between barcode and RFID may shift. But the principle of redundancy---providing multiple independent ways to identify and track items---will continue to be essential in a world where supply chains are increasingly complex and failure is increasingly costly. |
From fashion distribution centers to pharmaceutical supply chains, from returnable transport item pools to defense logistics, the dual-label has proven its value. It is not a temporary solution but a fundamental approach to identification that acknowledges the limitations of any single technology and harnesses the strengths of multiple complementary technologies. |
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Summary |
This chapter has explored the dual-label approach in logistics---the combination of a barcode and an RFID inlay on a single shipping label. Key points include: |
1. The dual-label provides redundancy, ensuring that if one identification method fails, the other can still provide the required information. This resilience is essential in high-throughput logistics environments where downtime is costly. |
2. Barcodes and RFID have complementary capabilities. Barcodes require line-of-sight but are inexpensive and universally compatible. RFID enables bulk reading without line-of-sight but is more expensive and requires specialized equipment. |
3. GS1-128 and Data Matrix are the predominant barcode symbologies for modern logistics, providing structured data encoding with Application Identifiers that give context to the numeric data. |
4. Code 39, despite being introduced in 1974, remains in widespread use due to its self-checking property, alphanumeric capability, and near-universal scanner compatibility. Its low data density is a limitation that has driven adoption of other symbologies for space-constrained applications. |
5. Fashion retail has adopted dual-labels extensively for item-level serialization, vendor compliance, and automated order validation with RFID tunnels. One implementation achieved a 17% reduction in shipping discrepancies. |
6. Pharmaceutical logistics uses DataMatrix for regulatory compliance and RFID for automated handling and cold chain monitoring. The healthcare industry's HIBC standard builds on Code 39. |
7. Returnable transport item tracking uses dual-labels to enable both automated RFID reading at logistics hubs and barcode scanning by partners without RFID capability. A system tracking over 90,000 RTIs achieved real-time visibility and demand forecasting capabilities. |
8. Automated warehouses use dual-labels for sortation, pick-to-light systems, and verification. Two-sided labels, where identical barcodes are applied to multiple faces of a carton, address orientation challenges in automated sortation. |
9. Automotive logistics uses dual-labels for AIAG-compliant part labeling, just-in-time supply chain tracking, and work-in-process monitoring. Code 39 remains prevalent due to the industry's long history with the symbology. |
10. Defense logistics relies on Code 39 through the LOGMARS and MIL-STD-130 standards. Infrastructure inertia keeps Code 39 in use even as newer symbologies are introduced. |
11. Third-party logistics providers use dual-labels to accommodate diverse customer requirements, supporting both RFID-capable and non-RFID-capable customers with a single label format. |
12. Implementation challenges include label design, print quality, environmental interference, data synchronization, and cost. Organizations should conduct thorough testing and plan for gradual adoption of RFID capabilities. |
13. Future trends include connected packaging, digital twins, AI-enhanced vision systems, and sustainability considerations. The dual-label approach provides a foundation for these more sophisticated applications. |
14. The persistence of Code 39 illustrates how technical characteristics---self-checking, alphanumeric encoding, scanner compatibility---combine with infrastructure inertia to determine technology adoption patterns. Code 39's role in military, automotive, and healthcare applications demonstrates the durability of embedded standards. |
15. The dual-label principle of redundancy will remain relevant as logistics systems evolve. No single technology is perfect, and the combination of complementary technologies provides the resilience that modern supply chains require. |
cs@easiersoft.com