Invention of the telephone useful and widespread apparatus it is now. The telephone exchange was an idea of the Hungarian engineer Tivadar Puskás (1844–1893) in 1876, while he was working for Thomas Edison on a telegraph exchange. Puskás was working on his idea for an electrical telegraph exchange when Alexander Graham Bell received the first patent for the telephone. This caused Puskás to take a fresh look at his own work and he refocused on perfecting a design for a telephone exchange. He then got in touch with the U.S. inventor Thomas Edison who liked the design. According to Edison, "Tivadar Puskas was the
Invention of the telephone in the art of instructing the deaf how to speak and experimented with the Leon Scott phonautograph in recording the vibrations of speech. This apparatus consists essentially of a thin membrane vibrated by the voice and carrying a light-weight stylus, which traces an undulatory line on a plate of smoked glass. The line is a graphic representation of the vibrations of the membrane and the waves of sound in the air. This background prepared Bell for work with spoken sound waves and electricity. He began his experiments in 1873-1874 with a harmonic telegraph, following the examples of Bourseul, Reis, and