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 the early 60s Western Union has put into operation transcontinental microwave system of data transmission via radio waves, completely replacing the web of telegraph poles and wires. July 3, 1884 the company's shares were included in the calculation base for the newly created stock index Dow Jones Transportation Average. In 1914 Western Union engineers invented the first payment card - a prototype of the modern credit card.