Issue #10 | January 6, 2005

This New Year, those of us in the RFID industry have one more reason to celebrate: the EPC Global UHF Generation II (Gen II) standard is ratified. Pass the confetti! Speaking as one member of the working group, I found it a remarkable process. I must publicly give huge kudos to Sue Hutchinson, the Hardware Action Group Facilitator, who has far more patience than I do. Sue deserves the thanks of all RFID users.

Now that we have a ratified standard, we actually have something to talk about.Instead of regurgitating EPC Global's press release as so much of the press is doing, let's put on our propeller hats and get geeky. There are elements here that merit a whole column, so bear with me.

The Gen II standard defines how communication occurs between the reader and the tag. (Since what are popularly called ?readers? also write , I shall use their more correct name here: interrogators.) Think of Gen II as a language that allows interrogators to read information from - and write information to - those humble little tags. A helpful analogy is that although we may speak the same language, not everyone's vocabulary is the same, nor is the speed at which we speak or process what we hear.

There are four different categories of commands in Gen II: mandatory, optional, proprietary, and custom (one of those concepts worthy of a future column). Gen II compliant equipment must support mandatory commands. Think of these as the basic, universal commands. Supporting optional commands is, well, optional - not required by these standards. But if an interrogator or a tag uses optional commands, it must be implemented according to standards specified by Gen II. Proprietary commands are not worth going into here, because they are only used in reader and tag manufacture and not by users. Suffice it to say these proprietary commands are disabled before equipment ships to you, anyway. Since custom commands are (you guessed it!) custom, no one of them has much to do with another. The good news is Gen II allows for them and therefore gives us all maximum flexibility.

Gen II operates in the 860 MHz to 960 MHz frequency range. Depending on what part of the world you are operating in, the frequency range used is in a subset of this range, determined by local radio regulations. For example: equipment designed for North America will operate in the 902 to 928 MHz range. You may hear people refer to "915" because that is approximately the mid-point in this range. What is most important is that this specified range is indeed diverse enough for global operations.

In environments containing numerous interrogators - "dense-interrogator environments" - the range and rate at which interrogators read tags can be improved by preventing interference from other interrogators. Again, going back to the language analogy, when multiple people speak at the same time, it is more difficult to hear a specific voice. One of the most subtle but important points is Gen II does not require interrogators to be designed for dense-interrogator operation. Additionally, the method which the interrogator uses to coexist with other interrogators is allowed to vary from manufacturer to manufacturer. That means that an interrogator from brand A may not work well with one from brand B, though they are both Gen II compatible.

As for your current equipment, some RFID readers on the market today will require hardware upgrades to support Gen II. This will be costly in time, if not in money. So do not buy another piece of equipment unless the manufacturer guarantees the only upgrade required is via firmware (their software), not hardware. Now that the standard is ratified, you should be able to get a definitive answer. You should also be able to apply firmware upgrades remotely. You do not want to have to physically visit every reader in the field to perform the upgrade. This will be handy for future upgrades, bug fixes, performance improvements, or to support newer standards.

Soon there will be a Gen II certification on any equipment you buy - or you are on your own. A reader is not Gen II compliant product unless it has received a written certification from EPC Global. This signifies it complies with all mandatory features, meets all local radio regulations, and has a license from the owner of any intellectual property utilized by the product.

Written by Louis Sirico
Copyright ? 2005 Louis Sirico