Switzerland's entry into the telephone age came in 1877, when the first experimental phone lines appeared, starting with a line linking the post office building with the Federal Palace and then with a link, using the existing telegraph line, between Bern and Thun. The following year, the government passed legislation establishing a monopoly on the country's telephone network. Nonetheless, private operators were allowed to bid for licenses in order to develop their local concessions. By 1880, Switzerland's first private network had been created in Zurich. This was a central system with the capacity for 200 lines. The first directory was also published that year and listed 140 subscribers.