Walkie-Talkie

Walkie talkies are handheld portable radios that use radio waves to communicate wirelessly on a single frequency band. They were first developed in the 1930s by a Canadian inventor named Donald Higgs and, quite independently, by an American named Alfred Gross. They were originally called two-way radios or pack sets, but as the thing that made them really stand out from telephones was the fact that you could both walk and talk at the same time, they became known as walkie talkies.

Each battery-powered handset contains a transmitter (which doubles as a receiver), an antenna for sending and receiving radio waves, a loudspeaker that also often functions as a microphone, and a 'push-to-talk' button that, unsurprisingly, you push to talk.

The loudspeaker-cum-microphone works like an intercom system. Because speakers and microphones contain what are essentially the same components – a magnet, a coil of wire, and a cone made of paper or plastic to receive or generate sound – they can be combined into a single device and the direction of the electrical current determines which function is given precedence. These features are separate in more sophisticated models.