Starting in 1894, Italian inventor Guglielmo Marconi began developing a wireless communication using the then newly discovered phenomenon of radio waves, showing by 1901 that they could be transmitted across the Atlantic Ocean.This was the start of wireless telegraphy by radio.Pigeon post had Persian roots, and was later used by the Romans to aid their military.
Telecommunication occurs when the exchange of information between communication participants includes the use of technology.
It is transmitted either electrically over physical media, such as cables, or via electromagnetic radiation.
Development of stereo FM broadcasting of radio took place from the 1930s on-wards in the United States and displaced AM as the dominant commercial standard by the 1960s, and by the 1970s in the United Kingdom.
On 25 March 1925, John Logie Baird was able to demonstrate the transmission of moving pictures at the London department store Selfridges.
After World War II, the experiments in television that had been interrupted were resumed, and it also became an important home entertainment broadcast medium.
On 11 September 1940, George Stibitz transmitted problems for his Complex Number Calculator in New York using a teletype, and received the computed results back at Dartmouth College in New Hampshire.
In the Middle Ages, chains of beacons were commonly used on hilltops as a means of relaying a signal.
Beacon chains suffered the drawback that they could only pass a single bit of information, so the meaning of the message such as "the enemy has been sighted" had to be agreed upon in advance.
Such transmission paths are often divided into communication channels which afford the advantages of multiplexing.