Ilustração de Sistemas de telefonia e distribuidor, gravuras de madeira, publicaram em 1897

Telephone systems and distributor; 1+3) Telephone by Siemens & Halske (Geramny); 2) Telephone by Alexander Graham Bell, cross section; 4) Telephone (1880) by Frederic Allen Gower (USA), 4a. closed, 4b. opened, 4c. removed sleeve with inserted iron membrane; 5) Telephone by Clément Ader (France); 6) Electromagnet system of a Telephone switchboard cabinet; 7) Telephone switchboard cabinet; 8) Front side view of a Telephone switchboard cabinet; 9) Cross section view of a Telephone switchboard cabinet. Wood engravings, published in 1897.