Phone SVG is a device for transmitting and receiving sound (mainly human speech) from a distance. Modern telephones transmit by means of electrical signals.
Phone SVG History
Before the invention of telegraphs (optical and electrical) and telephones, primitive methods such as whistling, gong, smoke signals or drumming were used to transmit messages over long distances. For example, a shot from a rifle can be heard from a distance of about ten kilometers; the audibility is greatly affected by loud noises in the vicinity; the signal can be distorted by extraneous shots. All of these devices were imperfect because of the distance dissipation of the sound: in order to transmit the signal as far as possible, it was necessary to create intermediate points on which other signalers, hearing the signal of the previous transmitter, transmitted the sound further. Part of the solution to this problem would be to transmit signals through water or metal, where the sound propagates at a higher rate and fades out a little later. The invention of a device that would use the properties of electricity to transmit and receive sound – the Phone SVG that is now in use – was preceded by the advent of the electric telegraph and its successful use during the first half of the 19th century.
In 1860, the naturalist Antonio Meucci published an article in the Italian newspaper New York City, in which he spoke about his invention, capable of transmitting sounds over electric wires. Mehucci named his apparatus Teletrofono. In 1871 he decided to patent Teletrofono, but because of financial problems could not do so.
In 1861, German physicist and inventor Johann Philippe Reis demonstrated another device that could also transmit musical tones and human speech over the wires. The device had an original microphone design, a power supply (galvanic battery, or – “local battery” MB) and a speaker. The Flight itself named the device Telephone designed by him.
Phone SVG, patented in the U.S. in 1876 by Alexander Bell, was called a “talking telegraph. Bell’s tube was used in turn for both transmission and reception of human speech. There was no call in A. Bell’s phone, later it was invented by A. Bell’s colleague – T. Watson (1878). The call of the subscriber was made through a tube by means of a whistle. The range of this line did not exceed 500 meters. For a long time Alexander Bell was considered to be the official inventor of the phone and only on June 11, 2002 the U.S. Congress recognized the right to invent the phone for Antonio Meucci in Resolution No. 269.
Alexander Bell applied to the Washington Patent Office for his invention on February 14, 1876. On the same day, inventor Elisha Grey from Chicago filed a preliminary application for the “Device for transmission and reception of vocal sounds by telegraph. Soon Grey refused his preliminary application. On this occasion, there were numerous disputes about who invented the phone first.
On March 7, 1876, Alexander Bell obtained a patent for the invention of the phone. Interestingly, Alexander Bell tried to invent not the phone, but “harmonic telegraph”. At that time, there was a huge shortage of lines in telegraphy.
June 25, 1876, Alexander Bell demonstrated his phone for the first time at the first World Electrotechnical Exhibition in Philadelphia.
In 1877, inventor Vaden used a telegraph key to call a subscriber, which closed the call chain (later the key was replaced by a button). In the same year, the St. Petersburg plant of the German company Siemens and Halské started to manufacture two telephone sets with two handsets – one for reception and the other for speech transmission.
In 1878, the Russian electrician P. M. Golubitsky used a capacitor in the telephone sets and developed the first Russian telephone of the original design, in which several permanent magnets were used. In 1885, Golubitsky developed a system of centralized power supply for microphones of telephone sets (the central battery system of the Central Bank).
In 1877-1878, Thomas Edison suggested that coal powder be used in coal microphones instead of coal rod, i.e. he invented a coal microphone with coal powder, which was used almost unchanged until the early 1990s, and in some places is still in operation.
The first phones were directly connected to each other from the office or residence of one client in another location. Being uncomfortable outside of a few clients, these systems were quickly replaced by manual centrifugal distribution boards. This led to the advent of fixed telephony, where each telephone was connected to a pair of dedicated wires to a local central office patch system, which had moved into fully automated systems since the early 1900s. For greater mobility, various radio systems were developed for transmission between mobile stations on ships and cars in the mid-20th century. A hand-held mobile phone was introduced for personal service from 1973 onwards.
A breakthrough in the field of long-distance telephone communications was the invention of the Russian military communications specialist G. G. Ignatiev. In 1879 – 1880 he was the first in the world to develop a system of simultaneous telegraphing and telephony over the same wire, with the division of frequencies of telephone and telegraph signal. This made it possible to use already existing telegraph lines for telephone communication. In 1881, the first line of the Ignatiev system connected the two military units, which were 14.5 km apart. The use of the condenser phone of P. M. Golubitsky and the “double microphone” system of E. A. Gvozdev made it possible to establish telephone communication via telegraph lines located between St. Petersburg and Moscow, as well as along all railways. Long-distance telephone communication between the two capitals was first established in 1889, and 9 years later, on December 31, 1898, a permanent fixed telephone line Moscow – St. Petersburg was opened. In 1883, a Belgian engineer F. van Rieselberg tried to develop a similar telephone and telegraph communication system by one wire. However, a comparative study of the Ignatiev and Rieselberg systems conducted in 1887 showed clear advantages of the domestic development.
The first commercial telephone conversation between New York and London took place on January 7, 1927 on a transatlantic telephone cable. The USSR was connected to New York via this cable on April 14, 1936. The first call took place between the communications commissioner and the duty officer of the New York Telegraph Company. Communication took place in the French language commonly used on international telephone lines.
During the Caribbean crisis, a direct line was created between the USSR and the United States.
The history of further development of the phone includes an electronic microphone, which finally replaced the coal, speakerphone, tone dialing, digital audio compression. New technologies: IP-telephony, ISDN, DSL, cellular communication, DECT.