An RFID or radio frequency identification device is often tagged to a product and used to read details about it from a receiver computer system from a few meters away, often around an obstacle etc that blocks the line of sight of the receiver from the RFID device. This device is the latest technology to be used in retail stores in their supply chain management systems. Its greatest benefit is automatic identification and tracking that does not require manual control and therefore can be done very quickly and efficiently.
The RFID technology was developed out of the military necessity to identify aircrafts as friendly or not, and to identify military shipments quickly without unpacking. The technology was developed for many years, starting from seminal work done as early as 1915, and has only in the last two decades become useful outside the military, especially after the granting of RFID related patents in 1983.
There are generally three types of RFIDs according to the way they transmit signals. The first kind, and the one that has been most widely used, is the active RFID. This device contains a battery that is used to power up the device and let it transmit radio frequency signals by itself. The second kind is a passive RFID device. This device does not come with an in built power source like a battery,and stays inactive until it is provoked from outside to transmit signals. Lastly, there is the battery assisted passive type of radio frequency device. This has an internal battery, but it does not automatically transmit signal by itself. An external source is required to start transmission, but once it starts transmitting, the battery takes over and controls the process. This results in a passive RFID device with the ability to transmit signals at a much longer range.
One of the earliest use of the RFID was as a passive device, and it was used both by the Soviets and the Americans during the Cold War as an espionage device.