Telegraphs played a large role in the formation of modern society. Slow and unreliable transmission of information hindered progress, and people were looking for ways to speed it up. With the invention of electricity, it became possible to create devices that instantly transmit important data over long distances.
At the dawn of history
The telegraph in different incarnations is the oldest of the types of communication. Even in ancient centuries, the need arose to transmit information from a distance. So, in Africa, tom-tom drums were used to transmit various messages, in Europe - a bonfire, and later - a semaphore connection. The first semaphore telegraph was first called "tachograph" - "scribbler", but then replaced it with a more appropriate purpose called "telegraph" - "long-distance copywriter".
First apparatus
With the discovery of the phenomenon of “electricity” and especially after the remarkable studies of Danish scientist Hans Christian Oersted (founder of the theory of electromagnetism) and Italian scientist Alessandro Volta - the creator of the first galvanic cell and the first battery (it was then called the “voltaic pole”) - many ideas appeared for creating an electromagnetic telegraph .
Attempts to manufacture electrical devices that transmit certain signals at a certain distance have been undertaken since the end of the 18th century. In 1774, the simplest telegraph apparatus was built in Switzerland (Geneva) by the scientist and inventor Lesage. He connected two transceivers with 24 insulated wires. When applying a pulse using an electric machine to one of the wires of the first device, the elder ball of the corresponding electroscope deflected on the second. Then the technology was improved by the researcher Lomon (1787), replacing 24 wires with one. However, this system can hardly be called a telegraph.
Telegraphs continued to improve. For example, the French physicist Andre Marie Ampère created a transmission device, consisting of 25 magnetic arrows suspended from the axes, and 50 wires. True, the bulkiness of the device made such a device almost unusable.
Schilling apparatus
Russian (Soviet) textbooks indicate that the first telegraph apparatus, which differed from its predecessors in efficiency, simplicity, and reliability, was designed in Russia by Pavel Lvovich Schilling in 1832. Naturally, some countries dispute this claim, “promoting” their equally talented scientists.
The works of P. L. Schilling (many of them, unfortunately, have not yet been published) in the field of telegraphy contain many interesting projects of electric telegraph apparatus. Baron Schilling’s device was equipped with keys that switched the electric current in the wires connecting the transmitting and receiving devices.
The first telegram in the world, consisting of 10 words, was transmitted on October 21, 1832 from a telegraph apparatus installed in the apartment of Pavel Lvovich Schilling. The inventor also developed a cable laying project for connecting telegraph devices along the bottom of the Gulf of Finland between Peterhof and Kronstadt.
Telegraph circuit
The receiving device consisted of coils, each of which was connected to the connecting wires, and magnetic arrows suspended above the coils on threads. On the same threads one circle was fixed, painted on one side in black and on the other in white. When the transmitter key was pressed, the magnetic arrow above the coil deflected and moved the circle to the appropriate position. The telegraph operator at the reception by the special alphabet (code) determined the transmitted sign by combinations of the arrangement of the circles.
At first, eight wires were required for communication, then their number was reduced to two. For the operation of such a telegraph apparatus, P. L. Schilling developed a special code. All subsequent telegraph inventors used transmission coding principles.
Other developments
Almost simultaneously, telegraphs of a similar design, using current induction, were developed by German scientists Weber and Gaus. Already in 1833 they carried out a telegraph line at the University of Gottingen (Lower Saxony) between the astronomical and magnetic observatories.
It is known for certain that the Schilling apparatus served as a prototype for the telegraph of the British Cook and Winston. Cook met with the works of the Russian inventor at the University of Heidelberg (Germany). Together with ally Winston, they improved the apparatus and patented. The device enjoyed great commercial success in Europe.
Steinheil made a small revolution in 1838. Not only did he run the first telegraph line over a long distance (5 km), he also accidentally made the discovery that only one wire can be used to transmit signals (grounding plays the role of the second).
Morse telegraph apparatus
However, all of the listed devices with dial indicators and magnetic hands had an irreparable flaw - they could not be stabilized: errors occurred during the fast transfer of information, and the text was distorted. The American artist and inventor Samuel Morse was able to finish the work on creating a simple and reliable telegraphic circuit with two wires. He developed and applied a telegraph code in which each letter of the alphabet was designated by certain combinations of dots and dashes.
The Morse telegraph apparatus is very simple. To close and interrupt the current, use a key (manipulator). It consists of a lever made of metal, the axis of which communicates with a linear wire. One end of the manipulator lever is pressed by a spring against a metal protrusion connected by a wire to the receiving device and to the ground (grounding is used). When the telegraph operator presses on the other end of the lever, it touches the other protrusion connected by a wire to the battery. At this moment, the current rushes along the line to the receiving device located in another place.
At the receiving station on a special drum a narrow ribbon of paper is wound, continuously moved by a clockwork. Under the influence of the incoming current, an electromagnet attracts an iron rod to itself, which pierces the paper, thereby forming a sequence of signs.
Inventions of Academician Jacobi
In the period from 1839 to 1850, a Russian scientist, academician B.S. Jacobi, created several types of telegraph apparatus: writing, arrow synchronous-common mode and the world's first direct-printing telegraph apparatus. The latest invention has become a new milestone in the development of communication systems. Agree, it is much more convenient to immediately read the telegram sent than to spend time deciphering it.
The Jacobi transmission printing press consisted of a dial with an arrow and a contact drum. Letters and numbers were applied on the outer circle of the dial. The receiving device had a dial with an arrow, and in addition, promoting and printing electromagnets and a typical wheel. All letters and numbers were engraved on a typical wheel. When starting up the transmitting device from current pulses coming from the line, the printing electromagnet of the receiving device worked, pressed a paper tape to a typical wheel and imprinted the accepted sign on paper.
Yuz's device
The American inventor David Edward Hughes approved the method of synchronous operation in telegraphy by constructing in 1855 a direct-printing telegraph apparatus with a typical continuous rotation wheel. The transmitter of this unit was a piano-type keyboard, with 28 white and black keys, on which letters and numbers were applied.
In 1865, Hughes devices were installed to organize telegraph communication between St. Petersburg and Moscow, and then spread throughout Russia. These devices were widely used until the 30s of the XX century.
Bodo apparatus
The Hughes apparatus could not provide high-speed cabling and efficient use of the communication line. Therefore, these devices were replaced by multiple telegraph devices, designed in 1874 by the French engineer Georges Emile Bodot.
The Bodo apparatus allows the simultaneous transmission of several telegrams in both directions to several telegraphists on the same line. The device contains a distributor and several transmitting and receiving devices. The transmitter keyboard consists of five keys. To increase the efficiency of using the communication line in the Bodo apparatus, such a transmitter device is used in which the transmitted information is manually encoded by the telegraph operator.
Operating principle
The transmitting device (keyboard) of the apparatus of one station is automatically connected via a line for short periods of time to the corresponding receiving devices. The sequence of their connection and the accuracy of the coincidence of the switching times are provided by the distributors. The speed of the telegraph operator must match the work of the dispensers. The brushes of the transmit and receive distributors must rotate synchronously and in phase. Depending on the number of transmitting and receiving devices connected to the distributor, the productivity of the Bodo telegraph apparatus ranges from 2500-5000 words per hour.
The first Bodo devices were installed on the telegraphic communication Petersburg-Moscow in 1904. In the future, these devices were widely used in the telegraph network of the USSR and were used until the 50s.
Start-stop device
The start-stop telegraph apparatus marked a new stage in the development of telegraph technology. The device is small and easier to use. It first used a typewriter-type keyboard. These advantages led to the fact that by the end of the 50s, Bodo devices were completely supplanted from telegraph points.
A large contribution to the development of domestic start-stop devices was made by A.F. Shorin and L.I. Treml, according to the development of which the domestic industry began to produce new telegraph systems in 1929. Since 1935, the production of devices of the ST-35 model began, in the 1960s an automatic transmitter (transmitter) and an automatic receiver (reperforator) were developed for them.
Encoding
Since ST-35 devices were used for telegraph communication in parallel with Bodo devices, a special code No. 1 was developed for them, which differed from the generally accepted international code for start-stop devices (code No. 2).
After the decommissioning of Bodo devices, there was no need to use a non-standard start-stop code in our country, and the entire existing ST-35 fleet was transferred to international code No. 2. The devices themselves, both modernized and of a new design, were named ST-2M and STA-2M (with automation prefixes).
Roll devices
Further developments in the USSR were incited to create a highly efficient roll telegraph apparatus. Its peculiarity is that the text is printed line by line on a wide sheet of paper, like a matrix printer. High productivity and the ability to transmit large amounts of information were important not only for ordinary citizens, but for business entities and government agencies.
- The roll telegraph T-63 is equipped with three registers: Latin, Russian and digital. Using punched tape can automatically receive and transmit data. Printing takes place on a roll of paper 210 mm wide.
- The automated roll-in electronic telegraph apparatus RTA-80 allows both manual dialing and automatic transmission and reception of correspondence.
- The RTM-51 and PTA-50-2 devices for recording messages use 13-mm ribbon and standard-width roll paper (215 mm). The machine prints up to 430 characters per minute.
Latest time
Telegraphs, photos of which can be found on the pages of publications and in museum displays, have played a significant role in accelerating progress. Despite the rapid development of telephone communications, these devices did not go into oblivion, but evolved into modern faxes and more advanced electronic telegraphs.
Officially, the last wired telegraph operating in the Indian state of Goa was closed on July 14, 2014. Despite the huge demand (5000 telegrams daily), the service was unprofitable. In the United States, the latest telegraph company, Western Union, ceased to perform direct functions in 2006, focusing on remittances. Meanwhile, the era of telegraphs did not end, but moved into the electronic environment. The Central Telegraph of Russia, although it has significantly reduced its staff, is still fulfilling its duties, since not every village on a vast territory has the opportunity to draw a telephone line and the Internet.
In the newest period, telegraph communication was carried out via frequency telegraphy channels, organized mainly by cable and radio-relay communication lines. The main advantage of frequency telegraphy is that it allows you to organize from 17 to 44 telegraph channels in one standard telephone channel. In addition, frequency telegraphy makes it possible to communicate virtually any distance. A communication network composed of frequency telegraphy channels is easy to maintain and also flexible, which allows you to create bypass directions in the event of a failure of linear means of the main direction. Frequency telegraphy has turned out to be so convenient, economical, and reliable that DC telegraph channels are currently being used less and less.