A simplified radio control panel with a Volume knob, a Squelch knob, a push-to-talk button on the side, an antenna and a speaker. Next to it a panel shows what comes out of the speaker. With squelch set low the speaker gives a loud hiss even though nobody is transmitting. The squelch knob is turned up and the hiss disappears. Another station transmits and its voice comes through. Volume only changes how loud the output is. When push-to-talk is held the radio transmits: a red lamp lights, waves leave the antenna and the speaker stops receiving. Releasing the button returns the radio to receive.
