With the invention of the telescope, the freedom of research to develop communication means increased, and in 1793 Claude Chappe (1763-1805) of France set up a communication tower called the semaphore, 230 kilometers between Paris and Lille, about 10 Arranged at kilometer intervals. A large arm tree (Udegi) that can change its shape was installed on the tower, and this change in shape was observed and read by a telescope, and relayed one after another. It is said that the change of the arm corresponds to 192 kinds of codes and conveys a complicated meaning. The system provided good news that French troops regained Lucenoy on August 15, 1794, during the French Revolution, and then two weeks later received news that they had occupied Conde. This event made the French Revolutionary government aware of the importance of the system, and the communication network of Semahall was set up in the country. In 1795, France was covered by a network of 556 semaholes with a total length of 4,800 kilometers. However, the cost of constructing large communication towers one after another increased, and the economy became tight. Only military needs propelled the construction, and only the profits of the lottery stopped its suspension. Shap died in 1805, but the tensions and anxieties of his later years were reportedly intolerable.

It was in 1800 by Jonathan Grout that the first visual communication system based on the Semahall principle was built in the United States. It was conducted on the transmission line between Boston and Martha's Vineyard Island, about 104 kilometers south of it, to send news to merchant ships arriving at the port. At that time, no one doubted that visual communication was the fastest means of communication.

History of Telecommunication