The Secret Life of Machines - Season 2 Episode 4 The Secret Life of the Telephone

The forerunner of the telephone was the telegraph. By 1870 all major towns in Europe and America had telegraphs, sending messages in 'on' and 'off' pulses (e.g. Morse code). It was while trying to improve the telegraph that Bell discovered the telephone. Episode Contents: Models: A tiny telephone system (less power supply!). A speaker using solenoid coil, magnet and base drum. A homemade microphone of plastic lid and carbon particles Machines: A cheeky store automaton that induces rabid commercialism. An acoustic probe by Rex. Guests: Several old telegraph machines using odd protocols. A 60s era mechanical "click and bang" telephone exchange (they are fun to watch). A funky 30's era burglar alarm complete with telephone dialer and a message for the police on the phonograph. Films: The cartoon life of that famous scot/canuck Alexander Graham Bell. An all singing all dancing Bell film promoting a phone every five feet. Extro: Stop motion phones.