A transponder is a wireless communication, monitoring or control device that picks up and automatically responds to an incoming signal. It is an electronic device that produces a response when it receives a radio-frequency interrogation. The term "transponder" is a blend of transmitter and responder. Transponders are used for detecting, identifying, and locating objects, but they can also be used in other technologies, such as in satellites to relay communication signals.
There are different types of transponders, and they can be used in various fields, such as telecommunications, air navigation, radio, optical fiber communications, and sonar. In air navigation, transponders are used to assist in identifying aircraft on air traffic control radar. Collision avoidance systems also use transponder transmissions as a means of detecting aircraft at risk of colliding with each other. In the transportation industry, transponder numbers are commonly used in aircraft safety and highway administration.
Transponders can be found in both civilian and military aircraft and in objects such as car keys. Simple active transponders are employed in location, identification, and navigation systems for commercial and private aircraft. An example of a transponder is a radio frequency identification (RFID) device that transmits a coded signal when it receives a request from a monitoring or control point.
In summary, a transponder is a wireless communication, monitoring, or control device that automatically responds to an incoming signal. It is used in various fields such as telecommunications, air navigation, and transportation.
