History leading to telecommunications
It can be said that the development of communication technology is an extension of the invention of various methods to compensate for the lack of sight and hearing since human beings had no letters.
It is said that it was around the 13th century BC that the Greek army relayed fire and reported the victory to its homeland during the war between Greece and Troya. Persian ruler Kiros Kyros (around 550 BC) deployed a row of towers radiating from the capital and placed soldiers on top of them to send messages one after another. According to legend, Alexander the Great made soldiers' voices reach 19 kilometers with a huge megaphone installed in a similar tower. It is said that the Ashanti people in Ghana can still use the special drum communication inherited from their ancestors more than 2000 years ago. The signal used by the indigenous peoples of the western United States is well known, but it has also been used worldwide since prehistoric times.
Communication after the invention of letters began to take the form of letters, and Hikyaku and Hayauma appeared as means of this transmission. Letters excel in traditional communication methods in terms of communication accuracy and abundant traffic, but they are considerably inferior in terms of the time it takes to deliver them. Homing pigeons were used to shorten the time, but it is undeniable that the certainty of delivery is low.