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Alexander Graham Bell discovered that he was able to transmit sounds using a method which consisted in a needle vibrating in water, that caused the electrical current to change. And this change in current was what transmitted the sound. This telephone consisted of a thin sheet of metal (called a diaphragm) held in front of an electromagnet.
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Telephones are mobile devices which function is to communicate with people without depending where they are. It transmits the voice and the sound with electric or electromagnetic impulses. During the pass of the years, it had developed and nowadays it continue improving. It started being something that mostly anyone had it, to something necessary for everybody.
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It was made by Scott and Wollaston in England. It was used in the General Post Office. Due to the size of the receiver, users listened through speaking tubes.
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It was invented by Almon Brown Strowger. It' s the first phone that could dial out, without an operator.
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John and Charles Erickson invented this phone. The rotatory phone allows for specific number dialing through a series of pulses controlled by a user dial. And, by picking up the phone, a user could connect to another telephone automatically.
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The AEG Telecar CD was the first mobile phone. It was bulky and heavy and also very expensive.
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The first smartphone was the IBM Simon. It consisted in a touch screen, without botons, predictive text, appointment book and other functions that now a days we still having in our mobile phones.
