Radio frequency identification (RFID)

A technology that uses electromagnetic or electrostatic coupling in the radio frequency (RF) portion of the electromagnetic spectrum to identify a specific device. Each RFID tag includes a unique identifier, so that when a nearby antenna/transceiver actives the tag, it transmits that identifier back to the antenna where that value is recorded or used to trigger some kind of action. For example, most modern toll-road systems use RFID devices that drivers attach to the windshield of their car, and each time a device is “read” by an antenna, the vehicle owner’s toll balance is incremented by the cost of that transit. RFID devices may also be used to track individuals (carrying tags), equipment (bearing tags), and so forth, within the premises of an enterprise for security monitoring.