There are several different levels of RFID tags, ranging from simple read-only devices to more powerful tags that can broadcast their own signal and require their own power source. The read-only chips are receiving all the hype because of the plans to deploy them in a retail environment.
Read-only RFID tags consist of a small computer chip and an antenna. When an RFID reader sends out a radio signal, the chips are powered up and respond with the information they contain. The energy required comes from the signal sent out by the reader.
To get an idea of what RFID tags look like, simply look at a book from a library or bookshop that has anti-theft devices - they are a primitive form of RFID tag. The sticker containing a strip of metal in a square spiral is the tag - the spiral is the antenna. Those chips are one-bit, they register either a '1' or a '0' which indicates to a reader whether the book should be taken out of the store.
Modern RFID tags hold a 128-bits of information, and are several orders of magnitude smaller.
Once the reader has received the 128-bit ID from the tag, it is sent to a PML (Physical Markup Language) server which looks up the appropriate IP address to retrieve the information on the product, according to IBM's wireless expert, Will Duckworth. "It looks like it's going to be Verisign who controls the database," he said.
The industry is hoping to avoid some problems that have plagued barcodes over the last quarter of a century.
"Every country has their own barcode system...you couldn't have one global barcode," Neil McKay, director Sun's Retail and CPG Industry group for Sun in Asia Pacific told ZDNet Australia . "With RFID a consortium was set up 4-5 years ago...to create one global standard."
Class 1 tags are read-only RFID devices that reveal the entire stored content when read.
There are five widely recognised classes of RFID tag:
Class 2 tags are read-write RFID devices that allow users to modify the content.
Class 3 tags are smart card tags with computing power. The encryption and authentication of these tags is supported by secret-key encryption.
Class 4 tags are smart card tags with computing power. The encryption and authentication of these tags is supported by public-key encryption.
Class 5 tags are RFID tags and sensor nodes with batteries or miniscule power generators. They function independently without an external power supply, and have a greater range than the other classes. They are not equipped with processors and have no computing power.
Source: Ubiquitous ID Center
The consortium, originally called the Auto-ID center, was formed in 1999 to create the standards required to make RFID tags global. The Auto-ID Center was a unique partnership between almost 100 global companies and five of the world's leading research universities; the Massachusetts Institute of Technology the US, the University of Cambridge in the UK, the University of Adelaide in Australia, Keio University in Japan, and the University of St. Gallen in Switzerland.
Last year the Auto-ID center morphed into EPCGlobal, and sets the electronic product code (EPC) for all the tags, and to issue those codes to every organisation globally that uses the technology.
"The outcome of all this is that the tags will become universal," said McKay. "The next step is to get a reader to operate in different countries...but the code number will be the same universally."
Which brings us to another problem. RFID tags are a wireless technology, and the frequencies used to read them vary from region to region, and in some cases from country to country. Although this is not ideal, there is unlikely to be a standard frequency in the foreseeable future because countries have already allocated much of the spectrum for different uses.
"Australia looks like it will be on 915 MHz, the same as the EU," said Duckworth, adding that there is currently no standard across Asia. It is possible to get dual frequency RFID tags and dual frequency readers, which will be required when goods are shipped overseas.
According to John Brand, vice president technology research services at Meta Group, RFID technology is subject to misreading tags up to 20 percent of the time, although the average is more like three to five percent. The failure rate of reading the chips is contingent on a range of environmental factors, since metal and water can interfere with the signal. If a wooden pallet soaks up water it can change the communications between the tags and the reader.
"There are a whole range of environmental factors that will determine the success rate, and that is not always science," said Brand. "There's a bit of science, art and magic to this."
