Chapter 2: The Birth of an Idea |
In Brief: This chapter traces the barcode's origin story---from a simple request by a grocery chain president to the 1949 patent filed by Norman Joseph Woodland and Bernard Silver for a circular 'bull's eye' design. We explore the Morse code inspiration, the technical ambition and practical limitations of the original concept, and then pivot to the eventual industry standard: Code 39. We will examine the technical characteristics of Code 39, particularly its self-checking property and alphanumeric capability, and illustrate how these features shaped its adoption across industries ranging from defense to healthcare and logistics. |
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1. Introduction: The Problem of the Modern Store |
In the mid-twentieth century, the American supermarket was a marvel of efficiency and abundance. Yet, beneath the gleaming linoleum and neatly stacked cans lay a logistical nightmare. The checkout process was a bottleneck of human labor and mechanical calculation. Clerks manually keyed prices into cash registers, a system prone to error, fatigue, and fraud. Inventory management was equally archaic; it relied on physical counts and paper logs, often resulting in stock-outs of popular items and waste of perishable goods. |
The industry needed automation. It needed a way to identify products instantly, accurately, and cheaply. As the story goes, in 1948, the president of a Philadelphia-area grocery store chain walked into the office of the dean at the Drexel Institute of Technology (now Drexel University) with a simple request: develop a system that could automatically read product information at the checkout counter. The dean, perhaps seeing it as a trivial problem, demurred. But the idea did not fall on deaf ears. |
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2. The Dreamers: Woodland and Silver |
The dean's rejection of the grocery executive's request was overheard by a graduate student, Bernard Silver. Silver, who would earn a master's degree in electrical engineering in 1949, was immediately intrigued by the challenge. He saw not a mundane retail problem, but a complex systems engineering puzzle. He shared his enthusiasm with a friend and fellow graduate student, Norman Joseph Woodland. |
Woodland was a different kind of thinker---more of an idealist and inventor. Born in Atlantic City, New Jersey, in 1921, he had an inquisitive mind. Together, this unlikely duo---Silver the pragmatic engineer and Woodland the creative visionary---formed a partnership that would eventually reshape global commerce. They began to work obsessively on the problem. They knew they were looking for a way to optically capture information, but the 'how' was an immense hurdle. It was a problem of data representation, read/write speed, and industrial reliability. |
2.1. The Beach Inspiration |
The legendary breakthrough came not in a laboratory, but on a beach. In the winter of 1949, Woodland was visiting his grandparents in Miami, Florida. Sitting on the sand, perhaps staring at the rhythmic waves, he began to think about the problem again. He was familiar with Morse code, a system of dots and dashes used in telegraphy. He started drawing in the sand, trying to translate the audio cues of Morse---short signals and long signals---into a visual format. |
His epiphany was to extend the idea of dots and dashes into a two-dimensional, linear pattern. He realized that by widening the 'dots' and 'dashes' into vertical bars of varying thicknesses, he could create a code that could be 'read' by a machine. The 'dots' became narrow bars, and the 'dashes' became wide bars. This simple, elegant concept---the translation of auditory patterns into visual symbols---formed the bedrock of the modern barcode. |
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3. The First Patent: The 'Bull's Eye' Design |
Woodland and Silver's initial patent application, filed in 1949 and granted in 1952 (US Patent 2,612,994), was not for the familiar linear barcode we see today. Their design was a circular arrangement of concentric rings, looking much like a target or a bull's eye. |
3.1. The Rationale for the Bull's Eye |
Why a bull's eyeThe primary answer is omnidirectional scanning. The inventors envisioned a system where a clerk wouldn't need to align the product with the scanner in a specific orientation. In a busy supermarket, fumbling with items to find the correct angle would waste precious seconds. A concentric pattern, by virtue of its geometric symmetry, could be read from any direction. A scanning beam hitting the center of the target could decode the pattern regardless of its rotational position. |
3.2. The Technical Challenge of Implementation |
While conceptually brilliant, the original patent had a fatal flaw: printability. Woodland and Silver's invention relied on the precision of printing. The design used a 500-watt incandescent light bulb and a large, unwieldy vacuum-tube photomultiplier to process data. It was hot, bulky, and impractical. |
Furthermore, the design of the concentric rings was a challenge for the printing technology of the 1950s. Printing processes of the era were prone to ink 'bleeding'---the tendency of liquid ink to spread slightly on the substrate. When printing horizontal lines, the bleeding is somewhat mitigated; the ink spreads along the length of the bar, while the edges remain relatively sharp. However, for a circular pattern, the ink bleeds in all directions, including radially. This caused the concentric rings to blur together, making them nearly impossible to read reliably. This was a critical lesson in the relationship between design and manufacturability. The optimal solution was a pattern where the ink would bleed in the direction of the bar (like a straight line), rather than across it. |
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4. The Wait for the Revolution |
In 1952, Woodland and Silver sold their patent to the Philco Corporation for a modest sum ($15,000) and Woodland took a job at IBM. He hoped to persuade IBM to invest in the technology. However, the company expressed only limited interest. The technology was far ahead of its time, requiring advanced electronics and printing capabilities that didn't yet exist commercially. Silver passed away in 1963, never seeing his vision become reality. Woodland would wait decades. |
It wasn't until the mid-1960s and 1970s that the technological pieces fell into place. The advent of solid-state lasers (specifically the helium-neon laser) provided a reliable and affordable light source for scanners. The development of integrated circuits made the decoding electronics small and cheap enough to be commercially viable. Finally, the Universal Product Code (UPC) was selected as the standard for grocery scanning, and the first commercial scan took place in an Ohio grocery store in 1974. The barcode revolution had begun. |
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5. The Workhorse: Code 39 |
While the UPC became the dominant barcode for retail point-of-sale, a different symbology became the standard for industry, logistics, and government: Code 39, also known as 'Code 3 of 9.' |
Introduced in 1974 by the Intermec Corporation, Code 39 was the first barcode symbology to encode not just numbers, but alphanumeric characters (letters and numbers). This seemingly simple expansion opened the door to a universe of applications far beyond pricing. It allowed for the encoding of serial numbers, part numbers, and complex identifiers that are essential to modern logistics and manufacturing. |
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5.1. Technical Characteristics of Code 39 |
To understand why Code 39 spread so pervasively across industries, we must first understand its mechanics. |
Encoding and Structure: Each character in Code 39 is represented by a pattern of nine elements: five bars and four spaces. Of these nine elements, exactly three are wide and six are narrow (hence the name 'Code 3 of 9'). |
The 'Self-Checking' Property: This is one of Code 39's most celebrated features. Because each character must have exactly three wide elements, the system is 'self-checking'. If a printing defect or scanner error causes a narrow bar to appear wide, or a wide bar to appear narrow, it would alter the total count of wide elements. The decoder would instantly recognize this as an invalid character and reject it. This built-in error detection capability makes it incredibly robust, eliminating the need for an obligatory check digit in many applications (though a modulo-43 check digit can be added for extra security). |
Variable Length: Code 39 is also variable-length, meaning it can encode strings of any length. While practically, most applications limit length to 20-50 characters to avoid impractically large labels, the flexibility is a major asset. |
The Quiet Zone: To ensure readability, Code 39 requires a 'quiet zone' of blank space on either side of the barcode. This zone must be at least 10 times the width of the narrowest bar (X-dimension) to separate the barcode from other markings on the packaging. |
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5.2. The Technical Advantage and Limitation: Why Code 39 |
The beauty of Code 39 is its simplicity and tolerance. Because it is self-checking and doesn't require a checksum calculation to decode, it is easy to generate and print. It can be printed at a wide range of resolutions, from high-density laser printers to impact dot-matrix printers. This makes it a very democratic technology. |
However, this simplicity comes at a cost: low data density. Because each character is composed of 9 elements with a two-wide-to-one-narrow width ratio, the barcode takes up a lot of physical space relative to the amount of data it stores. A 10-character string in Code 39 can be 40% wider than the same string encoded in Code 128, a more modern, denser symbology. This low density makes Code 39 unsuitable for applications where space is at a premium, such as small electronic components. But in situations where space is abundant, it is often the most reliable and cost-effective choice. |
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6. Industry Applications: A Code for Every Sector |
The technical characteristics of Code 39---its alphanumeric capability, self-checking reliability, and ease of printing---made it the dominant symbology for a wide array of non-retail applications. It became the language of asset tracking and inventory management across global supply chains. |
6.1. The U.S. Department of Defense (LOGMARS) |
One of the most significant early adopters of Code 39 was the U.S. Department of Defense. In the 1970s, the military faced a massive logistical challenge: tracking millions of parts, from nuts and bolts to high-tech weapon systems. The military developed the LOGMARS (Logistics Applications of Automated Marking and Reading Symbols) system, which mandated Code 39 as its standard for marking all items and supplies. |
The military's requirements perfectly aligned with Code 39's strengths. The labels had to be durable, capable of being printed on various materials, and readable in harsh environments. The self-checking property provided crucial error resistance without the need for complex checksum calculations in the field. The alphanumeric capability allowed for the encoding of National Stock Numbers (NSNs), which combine letters and numbers. Even today, Code 39 remains a mandatory standard for U.S. defense contractors under MIL-STD-130, securing its place in the defense supply chain. |
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6.2. The Automotive Industry (AIAG) |
The automotive industry, with its complex, international supply chains, was another major adopter. The Automotive Industry Action Group (AIAG) established standards for part identification that rely heavily on Code 39. From engine blocks to seat belts, every component in a modern car is marked with a barcode. |
The supply chain is long and complex: a Tier 3 supplier makes a bracket, a Tier 2 supplier assembles it into a larger module, and a Tier 1 supplier delivers it to the final assembly plant. Each step requires tracking for inventory management, work-in-progress control, and quality assurance. If a recall is issued for a defective batch of parts, that data must be instantly traceable back to the specific production run. Code 39's alphanumeric capacity allows for the encoding of a Part Number, a Supplier ID, and a Date Code, enabling full traceability. The low density is not a problem on a large part like a drive shaft or a seat frame. |
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6.3. The Healthcare Industry (HIBC) |
In healthcare, the stakes are life or death. The Health Industry Bar Code (HIBC) standard, which builds on Code 39, is used to label medical products, devices, and patient wristbands. |
Consider patient safety. If a nurse administers medication, they can scan the patient's wristband and the medication package. The barcode on the wristband encodes the patient ID and perhaps a date of birth. The barcode on the drug package encodes the drug type and dosage. A handheld scanner can quickly verify that the right drug is being given to the right patient at the right time, dramatically reducing medical errors. Hospitals also use Code 39 to track expensive equipment like infusion pumps and wheelchairs, and to manage blood bank inventory. The reliability of Code 39 is critical here; a misread could be catastrophic. |
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6.4. Asset Tracking and Inventory Management |
Beyond these specific industries, Code 39 has served as the default standard for internal asset tracking for decades. Libraries use it to track books. Tracking labels often use Code 39 because it is easy to print on an inexpensive label printer. In a warehouse, shelves are often labeled with Code 39 barcodes to guide pickers. In offices, employees use ID badges with Code 39 barcodes for access control and time tracking. The technology is simple, reliable, and the scanners are ubiquitous, making it an ideal 'backend' solution for a wide array of tracking needs. |
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6.5. Other Industries |
Code 39's reach extends even further. It is used in: |
Aerospace: Tracking aircraft parts and maintenance records. |
Electronics and Telecommunications: Tracking components during manufacturing. |
Furniture and Aluminum Manufacturing: Tracking work orders from the factory floor. |
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7. Summary: The Enduring Legacy |
From the sand of Miami Beach to the complex supply chains of the 21st century, the invention of the barcode is a testament to human ingenuity. Norman Joseph Woodland and Bernard Silver saw a problem---the manual inefficiency of a grocery store---and envisioned a solution rooted in the simplicity of Morse code. Their original 'bull's eye' design was a moment of brilliant insight, even if it was technologically ahead of its time and printability proved its undoing. |
The true explosion of the barcode into the industrial fabric of the world came with the advent of practical symbologies like Code 39. Its technical characteristics---the self-checking error detection, the ability to encode letters and numbers, and the freedom from mandatory checksums---made it a rugged, reliable tool for the harshest industrial environments and the most sensitive logistical operations. |
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While Code 39 may be less data-dense than later codes like Code 128 or 2D barcodes, its legacy is indelible. It provided the foundation for the global standardization of item identification. It was the engine that drove the efficiency of the LOGMARS program, the precision of automotive assembly lines, and the safety of hospital pharmacies. In many ways, the story of Woodland and Silver's idea is not just the story of a patent, but the story of how a simple thought---translated into a simple pattern of wide and narrow bars---could organize and track the complexities of the modern world. The birth of the barcode is the birth of the automated inventory, and with it, the birth of modern global commerce. |
cs@easiersoft.com