UID Part 3

Copyright © 2005 by Davis Multimedia, Int'l. All Rights Reserved.
As Printed in July 2005, Volume 31, No. 1 of The Engravers Journal
UID nameplates above courtesy of Imaging Systems Group, Horizons Inc., Cleveland, OH.

     Symbology”—another word to learn. It refers to the “study of symbols.” That’s what barcodes are; a form of symbol that conveys information—”Symbology.” Another term associated with barcodes and symbology is “machine readable identification” meaning information that can be read by machines (lasers or cameras) without human assistance. And now that we all understand that thoroughly, “So what?” “How do they work?” and, “Can you (someone in the engraving business) make any money from this?”
    Concerning the potential financial issue, just consider this. The U.S. Department of Defense now mandates permanent Direct Part Marking (DPM) or labeling using UID-compliant Data Matrix and often barcodes for a huge number of items to be purchased on all new contracts. Consider that much of this DPM or UID labeling can be produced using the existing equipment you probably have in your shop, such as your laser engraver, photometal processor and/or etching machine.
    This installment of the UID (Unique IDentification) series tries to give a snapshot of how barcodes, and more importantly, how Data Matrix works and what it looks like. This is not meant to be extensive, just an effort to convey the most basic information you need to know about this technology so you won’t be overwhelmed the first time you hear an engineer spouting a lot of verbiage that can be very confusing.
    First things first: “What is a barcode?” We see them everyday. They’re on virtually every product we purchase. They’re on the mail we receive, the UPS/Fed Ex packages that come and go from our businesses—they’re even on the cars we drive. Truth is they are now so commonplace that we don’t pay much attention to them.
    They’re just a part of our environment and most are pretty benign—they just carry a string of numbers that tell some computer what product the code is attached to and that, in turn, tells the computer how much to charge for it, when it was last serviced or any number of other tasks. They act like a “key” that unlocks the information in a database. Some people in the barcoding field call them a product’s “license plate.”
    Some codes can potentially put us at risk. Those that carry our checking account numbers, street addresses, medical records, credit information or other confidential information can be very sensitive. Thus far, I haven’t heard too much about anyone using these codes to steal identities or such, but the information is often there—in our trash cans, waiting for someone who has a reader and some software to “listen in on our lives.”
    Of course companies take lots of precautions to avoid this from happening, but we often don’t. I recently got a letter from Delta Air Lines that had a Data Matrix on it. Since I happened to have a reader available, I checked it out, and sure enough, there was my Frequent Flyer number. With that number and the name and address printed on the letter, a would-be thief could access my account. Then I started looking around and there was a lot of mail that had codes, many of which I couldn’t read with my handy-dandy reader, but codes nonetheless and someone, somewhere, was reading them. What was written in those codes? How sensitive was the information?
    These are just a couple of the ethical questions that have been around since the first barcodes appeared on the retail scene in the early 1970s. Barcodes had actually been around for some time and used in manufacturing applications such as the auto industry long before we became familiar with them. In fact, the only reason we see them today is probably because of Wal-Mart and other companies like them. As Wal-Mart began to grow, it encountered huge difficulties managing product, pricing, delivery and inventory, not to mention long lines at customer check out. This prompted them to insist that their suppliers provide barcodes on any product that Wal-Mart was to sell.
    Grocery stores were experiencing the same problems and they too were quick to adopt the new machine-readable technology. Once it started, everyone quickly got into the act—hardware stores, clothing stores, everyone.
    Likewise, the future holds a new kind of device far more powerful than a barcode and it’s coming to a retailer near you. These are called RFID (Radio Frequency Identification) devices and they’re small radio antenna-like devices that can spurt out all kinds of information when held close to a transceiver. They don’t need a battery since they’re energized by the transceiver which then reads the data in the tag. Anyway, that’s the future. Major companies have already begun using these devices in their packaging and Wal-Mart is among the first to try them. But we’re getting ahead of ourselves. Let’s back up to the very beginning of barcodes and get a better idea of how and why they work.

Figure 1: UPC codes are the codes you see on the products you buy.

Figure 2: Here you see the alpha representation and its corresponding linear barcode character.
     You’re probably most familiar with a barcode referred to as a UPC or Universal Product Code. These are the codes you see on all of the consumer products you buy (Fig. 1). They’re a series of vertical lines and spaces. The width and/or number of lines tell the reader what number the symbol represents. In Figure 2, you see a few alpha characters translated into barcode characters. The bars at the beginning and end of the barcode tell the reader that these are the starting and stopping points for that particular code.
    The reason the lines are both vertical and horizontal is to provide a more readable code. You’ve most likely been in line waiting patiently for the checkout person to try and scan an unreadable code. It might be covered with frost if it’s a frozen item or it might be damaged (Fig. 3) if the item has been around for awhile. The idea of the tall lines is that hopefully somewhere a tiny strip across the code will be readable. This is called “vertical redundancy.” It only takes a very small strip for the reader to interpret the code, but if the code is severely damaged or wrinkled and the spacing between the lines is altered, the reader gets confused and can’t correctly interpret the code. Another advantage to having tall, vertically redundant lines is that a scanner can even read the code on a slightly skewed angle, as show in Figure 4.
    If you were around in UPC’s earliest days, you might remember how many items couldn’t be read by the early readers and the information had to be entered manually. This process was frustrating for every one since that took far longer than it did for a good cashier to check people out usually before UPC. Today’s technology rarely misreads a barcode. Because of the way the lasers are mounted and tuned, they can read codes that are upside down, turned at an angle, damaged and even frost burdened (sometimes).
    So if UPC does so well, why are there so many different types of codes? And there are dozens of them. Many look much like the UPC code but they’re unique and rightly so.
    Remember the old adage, “Build a better mousetrap and customers will beat a path to your door?” Well, engineers have been trying to design the perfect symbology for years. Many code types, of course, never saw the light of day outside of a laboratory. Many are proprietary codes used by a single company to relay confidential information. Some are an attempt to solve a specific problem or meet a specific need such as those used by the Post Office, UPS, FedEx, etc.
    Pharmaceutical companies have played a dominant role in the life of barcodes and will also be a major player in the RFID devices already mentioned. They use them to track information about medications—when and where they were made, what batch, where the raw materials came from, who bought them, correct dosages, etc.

 
Figure 3: A damaged barcode can still be read because of the barcode’s vertical redundancy. Figure 4: Codes that are slightly skewed can also be read because of vertical redundancy.   Figure 5: These are examples of 1D Symbology.
1D vs. 2D Symbologies
    In a nutshell, there are at least two types of “barcodes” that we are interested in. The early codes were all one-dimensional codes and were made up of bars, thus the name, “barcode.” The reader sees these codes from left to right. There’s no information stored in the vertical dimension of the code. The only reason for the height of a barcode is so if one part of the code is damaged, the area above or below the damaged section should still be readable. This is that “vertical redundancy” issue mentioned earlier, whereby the bar pattern is extended so you can read the pattern anywhere from top to bottom.
    Barcodes are made up of bars and spaces. Most codes, such as the UPC code we’re so familiar with, are coded as two widths of lines and two widths of spaces within a space seven modules wide. All barcodes utilize a similar concept of alternating bars of black and white. Some barcodes allow only numbers to be used while others, such as Code 39, allow both letters and numbers. Still other barcodes, such as Code 128 allow 128 characters of the ASCII character set to be encoded. The way this is done is by having a start code and stop code with letters and numbers in between. Around each code is a “quiet zone” where nothing is printed. This is usually 1/4" on standard barcodes. This keeps the reading device from becoming confused by other codes, text or artwork that might be present. In Figure 2, you can see what a few letters of the alphabet look like in code. The samples in Figure 2 happen to be in Code 39 and you’ll notice each letter is made up of a combination of bars and spaces.
    In an effort to pack more and more information into a linear barcode (one read from side to side), three “densities” have been created. These work on the same principle but the width of the lines and spaces is less, allowing more information to be packed into a smaller space. They also make it more difficult to read accurately, which is why UPC codes are generally of a “light density.” If you look around however, you can easily find lots of examples of medium and high-density barcodes.
    Before we discuss Data Matrix which is what UID (Unique IDentification) uses, let’s take time to ask why it’s important to know a little about standard linear barcodes anyway? Although UID requires 2D Data Matrix symbols to be used, it also allows for, and even requires the use of other codes as well. In fact, where there’s room, the regulations (MIL-STD-130) encourage the use of both linear barcodes and “human readable information.” Human readable information is just ordinary text—letters and numbers. This is why you’ll encounter many labels that resemble the example in Figure 5.
    2D symbologies are often referred to as barcodes. Some are barcodes (those which contain “bars”) however a 2D Matrix doesn’t contain bars and therefore it really isn’t a barcode. What 2D symbols do beyond what barcodes can normally do is convey much larger amounts of information. The main difference lies in the fact that 2D symbologies store information in both vertical as well as horizontal directions, meaning the reading device must capture the image from top to bottom as well as from left to right in order to gather all of the coded data. This affords the storage of a great deal more information in a much smaller space. The Data Matrix symbology is certainly not the only 2D code in use. One source reported at least 20 different methods of accomplishing this task. Data Matrix is the form of symbology we are most interested in because it has been specified for use by the Department of Defense (DoD) for their Unique IDentification marking and ID standard. Because this is a member of the 2D family of codes, it does require special devices for “reading” and interpreting the codes.
 
Figure 6: In order to record large amounts of information multiple matrix units can be combined together. Figure 7: "Error correction" is built into Data Matrix code and can correct and verify information even when it has been severely damaged.   Figure 8: 2D Symbology stores information in both vertical as well as horizontal directions.
Advantages of 2D Symbology
    We’ve already talked about the amount of information that can be stored in a very small space but that’s only one of a host of advantages including easy scalability, use at varying sizes and the ability to do direct part marking (DPM) on a wide range of materials.
    One of the most discussed advantages is something called “error correction.” Data Matrix provides the means and ability to correct and verify information even when the printed image has been damaged (Fig. 7). Obviously, the ability to read damaged codes will depend on the amount of damage and where the damage occurs, making this a hotly debated claim, but nonetheless, error correction is at least an advantage of Data Matrix.
    A complete explanation of how information is encoded in a Data Matrix symbol with error correction is about as fascinating as watching paint dry, so leave it said, it does it—or at least, tries to.
What Does a Reading Device See When It Looks at a Data Matrix?
    A simple Data Matrix is a symbol containing 100 cells (10 cells by 10 cells). However a more complicated Data Matrix can contain many more cells. In fact, the more cells it has, the more information it can store. The cells can be round or square, dark print on a lighter background or a light print such as white on a darker background. Data Matrix symbols can be read accurately even when the amount of contrast is surprisingly low (as low as 20% or less). It can also be read when printed on glossy surfaces that contribute a high degree of reflectivity. Of course, the less reflectance and the more contrast, the better for everyone since these marks must be “verified” or tested for readability and graded accordingly. The more contrast, the more precise the marks and the least amount of reflection, the better the grade is likely to be.
    In order to record really huge amounts of information, multiple matrix units can be combined (concatenated) together (Fig. 6). Each matrix is read and the data combined to provide a continuous stream of text. A “quiet zone” around the matrix tells the reading device when text should or should not be combined.
    Along two adjacent sides of each Data Matrix is a solid line (or at least a solid row of connecting dots) along with a broken line on the other two sides. The decoding algorithms inside the readers use the solid lines to find the Data Matrix, including orientation, and the broken border is used for defining the “density” (rows and columns). Codes can be read from any direction (omnidirectionally) since the reader automatically orients itself. The combinations of black and white cells represent letters and numbers using a binary code just like your computer uses.
    The other advantage of this type of symbology is to provide the person reading the image with as much direct information as possible without having to link up to a mainframe computer. This is referred to as being a “portable database.” Most barcodes, especially in the early days, were never meant to be a database, only a “license plate” that linked to a host computer, which held all the appropriate information about the item. Without the host computer, the code was just a useless clump of numbers. In the case of a Data Matrix and its 2D cousins (Fig. 9), the hope is for the symbol to contain enough information that the host computer is not normally needed and such elements as a serial number, manufacturer, part number, date of manufacture or batch number can all be read immediately while more extensive information such as detailed service reports or sources of raw materials might be maintained on a remote host computer or on a DVD that can be accessed through a local computer, Internet access or satellite hookup.
 
Figure 9: Several examples of 2D Symbology.  
What Does The Future Hold?
    Clearly, the future is already here in the form of a new “barcode” called an RFID (Radio Frequency Identification). Invented many decades ago and patented in 1973, these are really not visible codes but tiny computer chips that can be attached to or embedded in many items. Perhaps the best-known application today is the implanting of a chip under the skin of pets or farm animals. This allows the animal to be positively identified should it be lost or stolen. It also allows farm animals to be tracked from birth until death. This makes it easy to track the history of an animal or their food products in the event of disease or an infectious outbreak. RFIDs are also being used in other devices such as cell phones, EZPass for toll booths and ExxonMobil’s SpeedPass. One seaport reportedly tracks 17,000 shipping containers per day using RFID chips.
    One of the companies pushing for this new chip is Wal-Mart, the world’s largest retailer. Wal-Mart and lots of other retailers, especially in the grocery industry, are greatly responsible for the mass acceptance of traditional barcodes some twenty years ago when they reportedly told their suppliers, “If you want us to sell your product, you’ll include a barcode.” The justification for RFID is simple—it will reduce labor cost significantly since there will no longer be a need for checkout cashiers. Just walk through the store, pick up whatever you want, put it in a bag and proceed to the checkout where all the items will be scanned at one time (automatically) without taking them out of the bags; your sale rung up and your credit card (which will also have a chip) charged—all with no human interaction whatsoever.
    Of course at the present time for UID marking purposes, the main application for RFIDs is for pallet identification
    Experts think the government, as well as most retailers will go to these as soon as mass production brings the price down from where it is now (about 50 cents) to a nickel. Some say the price will drop as low as a penny once they’re fully accepted. Already, some manufacturers are using them. Reportedly, Gillette recently purchased 500 million of them to include in their razors. Other companies already experimenting or using them include: Pepsi, Procter & Gamble and Coca Cola. The chips are so tiny they’re almost invisible, with a size of as little as 1/3 mm and as thin as a sheet of paper. They are nearly indestructible. One planted in a pair of jeans for instance cannot be damaged or demagnetized by washing or ironing them. In fact it generally takes a special “zapping machine” to disable an RFID chip.
    It’s no secret that the new Euro bills currently being made contain a chip. One chap has discovered a way to disable the chip by microwaving the bill. It causes the bills to burst into flames and destroys the bill but it disables the chip! Reportedly, this is also true with the new U.S. $20 bill as well; I tried microwaving several but nothing happened. Just think of it: If chips really are placed in money, at the end of the day you’ll be able to count huge amounts of bills in seconds. No longer will you have to stay until midnight counting your daily receipts!
    Developers claim these chips can be placed in food and eaten with no ill effects. (Are we really ready for that?).
    This discussion of RFID is much more than just a look into the future. It asks the question, “Will RFID replace barcodes in the very near future making any effect we make toward building a business marking government products a waste of time?” Those with whom I have spoken with say, “No!” First, widespread use of RFID is still five years away by the most conservative estimates. Others say they are still ten years in the future, or more. Even then, the consensus is that RFID will continue to be backed up with a machine readable code for years after they become commonplace. Initially, most RFID devices will probably be attached to the back of the label containing the barcode. This is not to say barcoding will never become obsolete, but it’s not likely in the immediate future.
    A perfect illustration of this redundancy is seen in today’s requirements. Although a Data Matrix code is required for all DoD equipment as specified in the regulations, it’s also required that, “when space permits,” readable text and linear barcodes also be included.
    Barcodes, 2D symbologies, RFID and 3D symbologies and barcodes (yes, codes can also be done in 3D), make for a myriad of languages, syntax issues, printing issues and manufacturing challenges. At first glance, I was tempted to just throw up my hands and say “let somebody else fool with all that stuff,” but before you do this, think of the potential market. The Federal Government spends trillions of dollars every year on “stuff.” Everything from toilet seats to screwdrivers and although not everything currently demands UID marking, eventually it probably will. Eventually, nearly every product made in the world, if it doesn’t already, will carry a Unique IDentification code of some kind.
    Most will be marked on the assembly line far from the likes of us. This is referred to as DPM (Direct Part Marking) or DPMI (Direct Part Marking Identification). But some of it, perhaps only a percent or two will need to be marked using labels made by individual contractors (engravers like us).
    Even if a company could capture 1/100th of one percent of this market, the sales numbers could be staggering. Will that become a reality? Will any engraving company in our industry ever capture even that tiny amount of business? I don’t know. But that’s what we’re talking about in this series—the potential for this exciting new market. For some engravers, it may not be a “good fit” but for those who are willing to take the chance, invest some money, learn the rules and make the calls, it could be incredibly interesting and profitable.
    In next month’s installment, we’ll consider some of the ways Data Matrix symbols can be created. In the meantime, check out EJ’s new website dedicated entirely to the UID market by visiting www.uidmarkinginfo.com. It’s a site that’s still in its infancy but designed to help you keep on top of this developing new market. If you know of information, websites or have experience working with UID, I would like to hear from you at sspence@engraversjournal.com.

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