== Patents ==* US 174,465 -- "Telegraphy" (Bell's first telephone patent) -- Alexander Graham Bell* US 186,787 -- "Electric Telegraphy" (permanent magnet receiver) -- Alexander Graham Bell* US 474,230 -- "Speaking Telegraph" (graphite transmitter) -- Thomas Edison* US 203,016 -- "Speaking Telephone" (carbon button transmitter) -- Thomas Edison* US 222,390 -- "Carbon Telephone" (carbon granules transmitter) -- Thomas Edison* US 485,311 -- "Telephone" (solid back carbon transmitter) -- Anthony C. White (Bell engineer) This design was used until 1925 and installed phones were used until the 1940s.
VoIP se je izkazal za prelomno tehnologijo, ki je hitro nadomestila tradicionalno infrastukturo telefonskega omrežja.