What is the purpose of a transponder?

The purpose of a transponder is to respond to interrogator signals. A transponder is an electronic device that receives radio frequency signals from an interrogator and automatically responds back with a specific information signal. This response can include identification data, location, altitude, and other critical information depending on the context in which the transponder is used, such as in aviation or military applications.

Transponders are widely used in air traffic control and radar systems, helping to distinguish between different aircraft and providing information that enhances safety and situational awareness. By responding to signals, transponders facilitate a two-way communication process, allowing systems to recognize and track various entities effectively.

In contrast, while tracking missile systems, relaying video feeds, and transmitting data directly are relevant functions within specific technological frameworks, they do not encapsulate the core role of a transponder, which is fundamentally about response to interrogation signals.