1700 BC – The First documented Communication in Visible spectrum 430-770 Thz, Fire signals used in the ancient Near East. While in Europe 1184 BC, as Homer tells of a chain of beacon fires prearranged to signal the return of Agamemnon’s fleet to Mycenae. Later also used smoke signals, optics, mirrors, flags and etc.
1729 – S.Gray’s discovery of electrical conduction.
1746 – Experimenters start to work on the application of electricity to communications at a distance in several countries.
1837 – The electric telegraph. 1844 – Morse’s practical telegraph (finger key & register).
1851 – ‘International’ Code (1848) adopted at the UTAG Telegraph Conference in Vienna. The signal ’73’ (used in Atlantic and Ohio Tel. Co.) possibly was originated as an extension of F.Smith’s phrases for telegraph (1845) , later ’73’ and new signals are used in St.Louis and New Orleans Tel. Co. As uniform signal codes (OK, GM, 73, 88…) are adopted in 1859.
1856 – Morse’s acoustic (sounder) telegraph system is introduced.
1865 – Founding of International Telegraph Union in Paris.
1865 – Manual of telegraphy designed for beginners. The first electrical telegraph amateurs appear, most of them learn and practice telegraph or use it for communication, they erect own telegraph lines and use key and sounder.