In the early forties of the 20th century, Western Union has used the first time a commercial intercity microwave transmission system. In the 30's of the twentieth century, Western Union has become the world's largest telegraph company. In October 1871 the company has implemented the world's first telegraph money order. After a century money transfers have become a major source of income for Western Union. In the 1910-1920 years. Western Union is actively engaged in researching, innovating in the field of data transmission. In 1884 Western Union has become a joint-stock company and was brought to the stock exchange. The company has entered in the first American stock index Dow Jones. Sibley, the founder of Western Union, did not build a new telegraph lines, and persuaded the other players to join. American Telegraph Company, however, still had to buy it.