Transponder
Videos
In telecommunications, a transponder is a device that, upon receiving a signal, emits a different signal in response. The term is a blend of transmitter and responder.
An Ontario Highway 407 toll transponder circa 2009
A transponder in a private plane squawking 2000
Radio-frequency identification uses electromagnetic fields to automatically identify and track tags attached to objects. An RFID system consists of a tiny radio transponder called a tag, a radio recei
Transponder
…a device that, upon receiving a signal, emits a different signal in response. The term is a blend of transmitter and responder. In air navigation or radio frequency identification, a flight transponder is an automated transceiver in an aircraft that emits a coded identifying signal in response to an interrogating received signal…
FasTrak, a 915 MHz RFID tag used for electronic toll collection in California
RFID hard tag
Electronic key for RFID based lock system
RFID antenna for vehicular access control