Chapter 43: The Obsolete - Standard Code 93 |
Executive Summary |
Code 93, developed in 1982, represents a fascinating 'what if' in the history of automatic identification. It was expressly designed to be a more compact, higher-density, and more secure alternative to the then-ubiquitous Code 39 symbology. Technically, it succeeded on all fronts: it was approximately 25% shorter for the same data, incorporated mandatory double check characters for error detection, and offered a more sophisticated encoding structure. Yet despite these clear advantages, Code 93 never achieved the widespread adoption its designers envisioned. It was briefly used in logistics and electronic component tracking, and found a niche with Canada Post for supplementary delivery information, but ultimately, the simultaneous rise of Code 128 and PDF417 rendered it largely obsolete. Code 128 offered even greater density and flexibility for linear applications, while PDF417 introduced the paradigm shift from one-dimensional lines to two-dimensional matrices, making Code 93 a solution in search of a problem. This chapter will explore the technical attributes of Code 93, its real-world applications across various industries, and the key factors that consigned it to the history books of barcode symbologies. |
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1. The Genesis of a 'Better' Barcode |
To understand the fate of Code 93, one must first appreciate the context of its birth. The early 1980s were a period of rapid growth for the automatic identification industry. The primary workhorse of the era was Code 39, a symbology developed in 1974. Code 39 was valued for its simplicity, its ability to encode alphanumeric data, and its self-checking nature . However, it had significant drawbacks. Its encoding structure---each character was made of five bars and four spaces, with three of the nine elements being wide---was inherently inefficient. This led to long, sprawling barcodes that consumed significant label space. The density of Code 39 was famously low, often cited as having a net efficiency of around 34% for a 100-bit message . |
It was in this environment that Intermec, a major player in the barcode industry, introduced Code 93 in 1982 . The stated goal was to create a symbology that could serve as a drop-in replacement for Code 39 but with superior performance. It was designed to be a high-density, variable-length, alphanumeric symbology that addressed Code 39's key weaknesses: its poor density and its lack of a mandatory error-checking mechanism . The name 'Code 93' itself is derived from its core structure, which the next section will detail. |
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2. Technical Anatomy: The 'Nine Modules and Three Bars' |
The technical design of Code 93 is a masterclass in efficiency compared to its predecessor. Every character in a Code 93 barcode is constructed from nine modules, arranged into three bars and their adjacent three spaces . This is a crucial distinction. While Code 39 uses a varying number of wide and narrow elements to encode data, Code 93 uses a more compact, 'continuous' structure where each character is defined by the width of its bars and spaces, which can range from one to four modules wide . This continuous nature eliminates the inter-character gap found in Code 39, allowing for tighter packing of data. |
The '93' nomenclature comes from this 9-module, 3-bar construction. The arrangement of these modules creates a 9-element code for each character, but with the constraint of exactly three bars and three spaces . This allows for a denser representation of data. The gross linear efficiency of Code 93 is a notable 61.7%, a significant improvement over Code 39's 37.4% . This means that for the same alphanumeric data, a Code 93 barcode would be notably shorter than a Code 39 barcode, often by about 25% . This was a critical advantage in applications where label space was at a premium. |
Another cornerstone of its design is its built-in data security. Code 93 mandates the use of two check characters, often referred to as the 'C' and 'K' check digits . These are calculated using a modulo 47 algorithm. Having two mandatory check digits provides a significantly higher level of error detection than Code 39, which traditionally did not require a check digit (though one could be optionally added). The double-check system was designed to make Code 93 exceptionally reliable, reducing the chance of misreads that could lead to costly data entry errors . |
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3. The Character Set: Versatility with a Catch |
Code 93 was designed to encode the standard 43-character set that users of Code 39 would recognize: the 26 uppercase letters (A-Z), the 10 digits (0-9), and a set of seven special characters (space, minus, plus, period, dollar sign, slash, and percent) . This core set made it directly compatible with the most common applications of Code 39. |
However, where Code 93 showed its ambition was in its ability to encode the full 128-character ASCII set. It does this through the use of four special 'shift' characters . By combining these shift characters with the standard 43 data characters, the symbology can represent all lowercase letters, control characters, and other special symbols that are part of the ASCII standard. This meant that Code 93 could theoretically be used in a wider range of applications that required more than just uppercase text, without needing to switch to a different symbology. |
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4. The Fall from Grace: Why Superiority Wasn't Enough |
Despite its technical superiority over Code 39, Code 93's commercial success was limited and short-lived. It was quickly eclipsed by other symbologies, a textbook case of how the best technology doesn't always win in the marketplace. |
4.1. Code 128: The Linear Champion |
The most formidable competitor was Code 128, which was also introduced in the early 1980s. Code 128 offered even greater density and efficiency than Code 93. With a gross linear efficiency of 60.8%, it is closely comparable to Code 93 on paper . However, Code 128's real advantage was its ability to encode all 128 ASCII characters directly and compactly without the need for shift characters. This made it a more straightforward and powerful tool for encoding data. |
Crucially, Code 128 became the foundation for several key industry standards, most notably GS1-128 (formerly UCC/EAN-128). This standard is used globally for supply chain logistics, enabling the encoding of application identifiers and complex data structures. This standardization gave Code 128 a massive ecosystem of support and adoption that Code 93 could never hope to match. Code 128 effectively became the default high-density linear barcode, rendering Code 93's niche largely redundant. |
4.2. The 2D Revolution: PDF417 |
While Code 128 was winning the linear space, a more profound revolution was underway: the transition from one-dimensional to two-dimensional barcodes. In 1991, Symbol Technologies introduced PDF417, a stacked linear symbology that could encode vast amounts of data---up to nearly two kilobytes---in a single symbol . PDF417 was capable of encoding not just alphanumeric data, but also full binary data, making it suitable for applications like driver's licenses, shipping labels, and identity cards. |
From an area efficiency perspective, the advantages were staggering. For a 20-character alphanumeric message, Code 93 would occupy approximately 7,100 square modules of area . In contrast, the area efficiency of stacked symbologies like PDF417 was an order of magnitude better, with comparable messages occupying between 290 and 670 square modules . PDF417 offered a solution to a problem Code 93 couldn't solve: how to fit large amounts of data into a small physical space. |
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5. Where Did Code 93 Actually Find a Home |
Despite its commercial failure, Code 93 was not unused. It found a few specific applications, primarily in sectors that valued its improved density and security over Code 39 but didn't yet need the capacity of Code 128 or 2D codes. Its main use cases were in logistics, electronics, and government mail. |
5.1. Logistics and Supply Chain Management |
In logistics, label space is often at a premium, and package identification requires speed and accuracy. Code 93's ability to encode a moderate amount of alphanumeric data---such as package identifiers, batch numbers, and routing information---in a smaller footprint than Code 39 made it a logical candidate . Barcode readers could easily be programmed to read Code 93, making it a viable option for internal tracking systems. While some sources suggest it was widely used in logistics , other, more specific sources indicate its use was more of a brief application rather than an industry standard . |
For example, in warehouse management, businesses could use Code 93 on shelf labels and bins to encode location and item data. Its double-check-character system provided an extra layer of security for these inventory counts, reducing the risk of miscounting expensive stock or misplacing critical items. The retail sector also found uses for it in product identification and inventory management, where the increased data density allowed for more information to be printed on smaller tags . The trade-off of using a less common symbology was manageable for closed-loop, internal systems. |
5.2. Electronics and Component Labeling |
In the electronics industry, components are often tiny, leaving very little room for labels. Code 93's high density and ability to encode alphanumeric strings (including the special symbols often found in part numbers) made it a suitable choice for labeling printed circuit boards and other small components . The double check characters were also valuable here, as a misread component could lead to a defective final product. The manufacturing sector used it for asset tracking and work-in-progress labels on the factory floor . |
5.3. The Canadian Postal System: A Niche Stronghold |
The most enduring and well-documented application of Code 93 is within the Canadian postal system. Canada Post uses Code 93 to encode supplementary delivery information on mail items . This is a classic example of a large, closed-loop system adopting a specific technology. Because Canada Post controlled the entire ecosystem---from the printing of labels to the scanning equipment in their sorting centers---they could implement Code 93 without worrying about its lack of support in the broader market. |
The symbology's capacity to encode a decent amount of information in a relatively narrow space, combined with its high level of data integrity, made it perfect for encoding additional routing or customer delivery instructions. It became a de facto standard within this specific application, and is arguably the most prominent use case of Code 93 still in existence today . |
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6. Conclusion: A Technological Success, a Market Failure |
Code 93 is a compelling case study in the business of technology. From a purely engineering perspective, it was a success. It achieved its primary design goals: to be a more compact, higher-density, and more secure version of Code 39. It offered a tangible improvement in efficiency and reliability, and it laid the groundwork for the full ASCII character set in a linear barcode. |
However, the market told a different story. Code 93 was caught in a classic technological pincer movement. On one side, Code 128 provided a 'better' answer to the same problem, with even greater density, direct ASCII encoding, and the crucial backing of industry standards like GS1-128. On the other side, the emergence of 2D symbologies like PDF417 offered a paradigm shift, solving problems that linear barcodes like Code 93 could never hope to address. The result was that Code 93, despite its merits, was squeezed out of the mainstream. It became a 'solution' that was simultaneously surpassed by an alternative within its own category and rendered obsolete by a new category of technology. |
Its legacy is not one of failure, but of bridging a gap. It served as an intermediate step, a proof of concept that high-density, secure barcodes were both possible and needed. Its adoption by Canada Post provides a stable example of a successful niche application. For the rest of the world, Code 93 serves as a powerful reminder that in the world of technology, technical superiority is no guarantee of commercial success. Market forces, standardization, and the relentless march of innovation ultimately decide the winners and losers. |
cs@easiersoft.com