The telegraph was invented by Samuel Morse, who also developed a system of signs that we know as the Morse code. They are the result of electrical signals trasmitted through huge distances using the properties of electromagnetism.
The morse code is obtained as a series of lines and points come to form a system of representing signs and language.
The telegraph quickly provided a means of communicating between the European and the American continent. Any relevant news then arrived in both continents and later where to be innovated in sectors like military.
The telegraph rendered to be a relatively low cost way of communication in the long term and enabled further developments in Communications and Transport sectors.