What is the purpose of the PTT button on a radio?

The purpose of the PTT (Push-To-Talk) button on a radio is to activate the transmitter and allow the user to speak. When the PTT button is pressed, it enables the microphone, allowing the user's voice to be transmitted over the radio waves to communicate with other users. When the button is released, the transmitter is deactivated, which allows the user to listen to incoming communications. This functionality is essential for maintaining clear and controlled communication in radio systems, especially in environments where multiple users may be talking over the same frequency.

The other options do not accurately describe the PTT button's function; for instance, switching the radio on and off or changing frequency channels involves different controls or settings that are not related to the PTT mechanism. Similarly, muting incoming signals does not pertain to the PTT functionality, as the button's primary role is to facilitate sending voice communication rather than managing incoming signals.