Radio Frequency Identification (RFID) is a technique that uses electromagnetic coupling in the radio frequency (RF) portion of the electromagnetic spectrum to uniquely identify objects, animals or people. Objects (often referred to as RFID tags) are applied or incorporated into products, animals or people for identification and tracking purposes. The advantage of RFID is that it does not require direct contact or line-of-sight scanning. The RFID system consists of three parts: an antenna and a transceiver (usually combined into a card reader) and a transponder (tag). The antenna uses radio frequency or magnetic (inductive) energy to transmit the signal that activates the transponder. When activated, the tag sends the data back to the antenna. This data is used to inform the computer what should happen. This action can be as simple as improving the access door, or as complex as the database interface for currency trading.