Radio Frequency Identification

RFID - what is it?   Radio frequency identification (RFID) is a generic term used to describe a system that transmits the identity of an object in the form of a unique serial number using radio waves.   It’s grouped under a broad category of automatic identification technologies.   Auto-ID technologies use bar codes, optical character readers and biometric technologies, and reduce the amount of time and labor needed to input data manually and to improve data accuracy.   Bar code systems often require a person to manually scan a label or tag to capture the data.   RFID is similar to bar code technology, but uses radio waves to capture data from tags rather than scanning the bar codes on a label and transmits this data to a computer system all without needing a person to be involved.   A typical RFID tag consists of a microchip attached to a radio antenna and these chips store as much as 2 kilobytes of data.   The stored data can include product information, date of manufacture, destination and sell by date.

RFID - a history.   Radio frequency identification can be traced back to World War II.   The Americans, British, Germans and Japanese were all using radar to warn of approaching planes which were still miles away.   The problem was there was no way to identify which planes belonged to the enemy and which were a country’s own or allied pilots returning from a mission.   The Germans discovered that if pilots rolled their planes as they returned to base, it changed the radio signal reflected back.   This crude method alerted ground crews these were German planes and not allied aircraft, and was essentially the first passive RFID system.  
The British worked on a secret project that developed the first active friend or foe (IFF) system.   Putting a transmitter on each plane, signals received from the radar stations on the ground were broadcasted back that identified the aircraft as friendly. RFID works on the same basic concept.   A signal is...