Telephone switchboard operator. The lights on the switchboard light up when someone makes a telephone call, allowing the operator to use the cables to make the required connection. The telephone was invented in 1876, with switchboards being redesigned in the 1890s and early 20th century to keep pace with technological changes and increasing demand. Photograph published in 'La Telegraphie Sans Fil' (Wireless Telegraphy, 1914), by the French geophysicist Alphonse Berget (1860-1934).