What is Radio Frequency Identification?

Radio Frequency Identification (RFID) is a technology that allows the identification of tagged items without a line of sight. It includes a tag, a reader and a computer system. A tag containing a tiny microchip and an antenna is placed on an object. Most of the tags, which usually carry information in the form of a unique serial number, require no external power. These tags are known as "passive" tags. When devices called readers are placed close to tagged objects, a low power signal is sent out to the tag. The tag "wakes up" and responds by transmitting its unique ID number back to the reader. The reader then sends the number to a computer system.

There are different ways in which tags and readers can communicate. In order to be able to "speak" to each other, tags and readers must follow the same set of standards, of which there are many. Not every reader can communicate with all types of tags.

Tags vary in size, depending mainly on the antenna. They can be very small and can be built into products or into labels which are attached to a product. Other tags are as big as the palm of one's hand and are attached to containers or pallets of goods. Some tags contain a great deal of information, others only a unique ID number.