In the early forties of the 20th century, Western Union has used the first time a commercial intercity microwave transmission system. Another invention of Western Union - time synchronization. July 3, 1884 the company's shares were included in the calculation base for the newly created stock index Dow Jones Transportation Average. 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.