An RFID FAQ

Provided courtesy of RFIDWizards.com

1. What is RFID?

Radio-frequency identification or RFID is an automatic identification method, similar to bar codes. Bar codes rely on a visual scan to collect data, while RFID relies on radio waves. Unlike bar codes, RFID does require a line-of-sight, can scan many tags in an area very quickly and even read them at a further distance.

2. How does it work?

There are four basic components to every RFID system:

1) RFID Tags

RFID tags are affixed to assets. Each has a unique numerical identifier so differentiation is possible. For supply chain operations, it is common for the tag identifier to contain the Serialized Global Trading Identification Number (SGTIN) of the item it is affixed to. This allows differentiation of two identical items.

RFID tags come in three configurations: passive, which have no internal power, and draw power from the reader; active, which contain a battery; or semi-passive, somewhere between the first two.

2) Interrogators (or readers)

An interrogator, or more often called a reader, is a radio frequency transmitting and receiving device used to communicate with a RFID tag. The device was named an interrogator because it interrogates the tags. The term reader is a more colloquial term, but is sometimes misleading in that many of these devices have the ability to encode, or write information to an RFID tag.

A reader basically acts as a sensor because it senses what tags are within its range.

Readers are designed to interface with an information process system, which we'll explain more about below.

3) Antennas

One or more antennas are connected to the reader and are required for the radio frequency communications between the tag and the reader. Antennas come in a variety of size and shapes and have a significant impact on read range.

4) RFID Information Possessing Systems

The readers must be connected to an information processing system. The information processing system provides instructions to the readers, collects output data from the readers, and most importantly, makes decisions based on business rules about the data it receives. The computer programs are sometimes called "middle-ware" or "edge-ware".

3. Where have I seen it before?

In hundreds of places. Security devices are some of the simplest RFID devices, like the ones tucked into books at a library or bookstore. Smart cards are another, like the key cards you use to enter secure buildings. The Exxon/Mobile Speedpass you use to buy gasoline is another common application. The ID tag buried between your dog's shoulder blades is an increasingly common application.

It is also in hundreds of places you have not seen, in services, industry, logistics and agriculture. Hospitals, factories and laboratories all use RFID tags in asset tracking, of high-value equipment. Fish and game departments use them, injected into fish or in wildlife, to track their movements. Logistics providers use them on trucks and railcars, which allow them to track the movement and the shipments inside. Manufacturers use them to track production: many auto makers mount RFID tags on chassis, allowing them to be tracked during assembly, automatically.

4. I hear of different tags, different frequencies—how can I choose?

There are numerous tag configurations and tag frequencies, and every RFID installation is unique.

You may need a ruggedized tag for harsh environments – for example, in industrial laundries, or in rail yards. You may need a simple tag with a unique identifier, or a "writable" tag on which you can put up to 64 bits of data.

Also, the frequency of the tag depends upon your commodity, and how you want to use the data. Generally, higher frequencies mean longer ranges and more data – but less is not always more.

Low frequency (LF) RFID transponders are less susceptible to interference by metals and liquids and is "omnidirectional" like a phone signal. You'll see these in animal tracking, on beer kegs and steel gas cyliners, and in inventorying automobiles.

High-frequency (HF) RFID has a range of about 1m, and offers high memory capabilities and decent read rates: you can read hundreds of tags per second, without interference, so it is a good choice for certain items. You'll find it used in bank cards, secure cards and contactless payments, and wristbands – the kind you see at theme parks and ski areas to track children.

VHF transponders are typically active transponders, which contain batteries which boost their range—some makers claim up to 300 ft.—so these are useful in tracking cargo containers, high-value moveable items, in tracking vehicles at checkpoints and such. These are among the most expensive tags, so may be practical in tracking high-value assets, or even high-value personnel like doctors, but not in access cards.

UHF is the "retail frequency" or the "supply chain frequency." The tags are comparatively low-cost, with a decent read range and read rate, and typically have room for considerable amounts of data. These are the tags that you see on cases and pallets, and the kind that are mandated by Wal-Mart, Sam's Club and the Department of Defense (DoD). These tags are the standard for electronic product codes (EPC).

5. Do I need help, or can I implement RFID myself?

It depends. Equipment manufacturers and RFID implementers are offering low-cost "starter kits," typically including one or two readers, a volume of tags, and some middleware.

However, RFID involves complex radio physics. In all but the simplest applications, you'll likely need someone with engineering and RFID experience to get the optimal use out of RFID.

6. Isn't there some security risk?

A very exaggerated one.

RFID detractors would have you believe that someone can point a reader at your wallet or handbag (or even your house), and read all your credit card information, see what pills you're taking, get your home address from your bank card, and use your Speedpass to buy gasoline.

Most RFID devices have very minimal data on them and none carry personal data about you. That data is contained in a secure database. The Speedpass contains one bit of data – "this is an authorized user." Similarly, your bank card, credit cards and pay passes contain no personal data.

In industrial applications, where writable tags are used, someone would have to have access to your enterprise system to make sense of the data and unique identifiers on that tag.

Keep in mind that most application use tags with security that would take a high speed computer months to crack.

7. Am I obliged to use RFID?

Yes, and no. Wal-Mart and its subsidiary Sam's Club mandate RFID from its suppliers. So too does the DoD. At one time, Wal-Mart made it absolutely mandatory from its largest suppliers, but eased its stance over time. Sam's Club has just announced a system of graduated fines for non-complying suppliers.

8. I hear it's unreliable.

It can be, if implemented incorrectly. But skilled implementers and trained users are achieving accuracy of up to 99.999 percent, well in excess of barcode accuracy of the average bar code, which only yields 85% accuracy.

9. Why can't I just use barcodes?

Barcode is a perfectly useful form of automatic identification, but limited. First, you need line of sight, where RFID can "read around corners."

Think of a shelf of books. To inventory each book, you would need to see the barcode—on the back of the book. So, you would need to pull each book off the shelf and scan the barcode. With RFID, you need only swipe a reader past the shelf.

True too, barcodes are limited in that they are identifiers, only. A barcode on a boxcar can identify that boxcar, only; the contents and its history would have to be in a database, in an enterprise system. A high-end, writable RFID tag can carry that data, if need be.

Most companies that offer barcode equipment have come to offer RFID equipment as well, with no plans to phase out barcode equipment.

10. I'm mandated to use it—how does it benefit me?

An excellent question, and one that Wal-Mart and DoD suppliers demanded.

Your suppliers demand it because it enables them to be more efficient, and save money. That means it can do the same for you.

Used right, RFID can increase efficiency and savings in several areas:

• Eliminating or reducing repetitive data entry, like the "travelers" that accompany work in process on a shop floor, or the paperwork at a shipping area.
• Reducing inventory, by giving you an accurate count, and eliminating the hours of manual labor in taking inventory.
• Speeding up check-in/check-out procedures, like trailers coming into or leaving a shipping area. Here too, RFID can ensure accuracy, matching the load to the driver, for instance.
• Tracking assets, and optimizing their use. Think of rental equipment, perhaps a rototiller. If you can't find it, you can't rent it out. RFID can pinpoint its location. The uses are limitless, and the return on investment mounts with every accurate delivery and easily-located asset.