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         The invention of the telephone marks an outstanding stage in the history of telecommunications, as this is the first device able to transmit sound in all its complexity: height, intensity and tamber.
         In 1860, a German professor Philippe Reisse achieved a device which could transmit music sounds with the help of electricity. He managed to commercialize his telephone, but the quality of the device was not allowing the transmission of speech.
The telephone was invented by the American Graham Bell who in 1876 prepared the first such device of practical utility. The paternity of the telephone was decided consequent to a trial due to the fact that 2 hours later than Bell, Elisha Gray also submitted a license request based on a similar structure.
         In 1877, Bell Telephone Company Edison was created and thus telephony entered the market. The same year, Western Union Company asked Thomas Edison to finalize a set so to compete with Bell Company. Edison created an emitter of variable resistance more sensitive than Bells’, which was to become the first graphite microphone (27 April 1877). One year later, David Hughes made a very sensitive microphone out of charcoal pencil.
         The first telephone sets were uncomfortable because the microphone and the receiver headphones were not fixed. Then, the microphone was fixed to the main body of the set, while the headphones were mobile. In 1882, a support was created for fixing the receiver headphones and the microphone. As for the power supply, telephonic posts used local and central batteries, according to the location of the power supply source of the microphone circuit.
         Due to the increasing number of users, telephones were connected to telephonic centrals. The first such device was inaugurated in Boston in 1877. At the beginning, centrals were manual, that they were used by operators. Like in the case of the telephones, the functioning of centrals depended on a local or central battery. The possibility of constructing automatic centrals was approached already in the last decades of the 19th century. The first central of Europe, installed in Amsterdam in 1898, was designed for 400 users.
         Telephony was at the beginning using telegraphic lines, but in time these proved to be insufficient. The multiplex system was adopted both in telephony and telegraphy as it enabled the simultaneous transmission on the same circuit of several phone calls. An important contribution in the field of multiple telephony was the one of Romanian engineer Augustin Maior (1882-1963) who in 1905 experimented multiple telephonic communications with the help of alternative currents of high frequency. Multiple and simultaneous telephony was made possible by the use of multi-wired and coaxial cables, which solved the problem of trans-oceanic connections.
         At the end of 1877, experiments with telephonic sets were carried out at the “Tierich&Leopolder” Factory of Telegraphic and Signaling Devices in Bucharest. In Moldavia, Titu Maiorescu, who was in Dorohoi, spoke on the phone with the Mihaileni station. In Iasi, in 1882, some Morse devices of the police stations were replaced with telephone sets. It was a communication system using the telegraphic line. The telephonic line was extended in 1887, public telephony was introduced in 1896 and automatic telephony in 1936.
         In 1883, the first manual central with five numbers was also installed. The first interurban communications were carried out on the Bucharest-Sinaia and Bucharest– Braila – Galati routes. În 1906, the first automatic central with 20 numbers was installed. Yet, automatic central became really important in 1927, when such a device with 300 numbers started functioning.

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