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Visible Light Communications
Alexander Graham Bell the inventor of the telephone, invents the photophone which transmitted his voice on sunlight over 200 metres. -
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Discovery of Radiowaves
Heinrich Hertz experimented using a spark gap attached to an induction and different spark gap connected to a receiver. When waves made by the sparks of the coil transmitter we picked up by the receiving antenna, sparks would jump its gap as well. Heinrich showed that the waves had all the properties of electromagnetic waves. Communication by radio waves is achieved by a radio antenna which transmits many signals and a resonator tunes onto a specific signal. -
First Microwave Message
The first message to sent using microwave radiation was sent from microwave towers from New York and Philidelphia. -
Telephone Microwave Communication
Communication through microwaves became widely used in the 1950’s with many telephone calls being carried by multiple microwave radio relays. -
Satellite Communication
Echo 1 one of the communications satellites is launched into space which relays signals using microwaves to different points on Earth. -
Infrared Remote Control
A Canadian Company called Viewstar Inc first used infrared to control a TV. Communication to devices over short distances using infrared became more common in the coming years. -
Microwave
Wireless connectivity (e.g. Bluetooth) operates using microwaves, because microwaves offer in-building penetration which means the signal can get through thick walls. -
Visible Light transmitting video.
A demonstration by Harold Haas at TED showed high definition video being transmitted from a LED lamp.