Indo-European telegraph line

from Wikipedia, the free encyclopedia

The Indo-European telegraph line, Indolinie for short , was a telegraph connection from London via Berlin , Warsaw , Odessa , Tehran to Calcutta . It was put into operation in 1870 and, apart from shutdowns due to the war during the First World War , was in operation until 1931.

history

British-Indian telegraph lines until World War I

Reasons to build

A functioning communications link between Great Britain and the most important colony of India has long been a goal of the British government. For this purpose, the Indo-European Telegraph Department was founded in 1863 . The land lines over Russia and Persia as well as Persia and Turkey were prone to failure. The dispatches had to be re-entered again and again at the intermediate stations by officials who only knew the local language, and thus led to communication difficulties and errors. The transmission of the first message from London to Calcutta took 6 days, 8 hours and 44 minutes. In addition, the dispatch fees were very high due to the operational involvement of several telegraph administrations. A submarine cable laid through the Red Sea in 1859 failed after a short time. The situation was utterly unsatisfactory.

Werner von Siemens offered to eliminate the problems by building a continuous, technically uniform line that was subject to a single administration. The dispatches should be carried by induction current without interruption.

Concessions and Financing

After lengthy negotiations, Siemens & Halske received the concession to build the line through Russia in 1867 and Persia in 1868. To finance this, the Indo-European Telegraph Company (IET) was founded in 1868 as a public company under English law with a capital of £ 450,000.

Existing lines

For the transmission from England to Prussia ( Lowestoft - Emden ) and in the former Hanover state territory, the cables of the Electric Company had to be used due to existing concessions . From Emden via Berlin to Thorn , the line in their national territory was made available to the operating company by the Prussian telegraph administration. The connection to the network operated by the British-Indian administration was to be made from Tehran. The Tehran – Buschir connection had existed since 1863, the Buschir – Karachi sea ​​line since 1864. The continuation to Calcutta was planned via the Indian inland network.

construction

The Indo-European Telegraph Company had to build the route Thorn - Warsaw - Zhitomir - Odessa - Kerch - Sukhumi - Tbilisi - Julfa - Tehran (4,700 km). Siemens & Halske took on the construction contract for £ 400,000. All parts of Siemens' overall business were involved in the construction. Siemens Brothers & Co. in London provided the material and laid the undersea cable through the Black Sea , Siemens & Halske Berlin and St. Petersburg were responsible for the construction. It was built on three sections (Russian, Caucasian and Persian parts) at the same time. About 70,000 masts, partly made of wood and partly of iron, had to be erected and wires 6 millimeters in diameter had to be laid. A submarine cable was laid between the Crimea and the eastern end of the Black Sea due to the impassable terrain . During the construction period, there were disputes about the level of fees for changing cables (see section “Economic efficiency”) .

Installation

The construction work was successfully completed at the beginning of 1870. The immediate commissioning prevented line interruptions due to the harsh winter and the inadequate training of the staff with the new apparatus system. After these difficulties had been resolved, the first exchange of telegrams on the 11,000 km route between London and Calcutta took place on April 12, 1870. After an hour the reply was back in London.

The successful company was a great gain in prestige for Siemens & Halske.

Communication technology

The transmitter from Siemens

Siemens & Halske used a punched tape telegraph with a crank inductor as an apparatus system. Using a crank mechanism, a coil was turned in the field of a permanent magnet and generated the current pulses for transmission. The input speed could be increased by using punched tape that was pulled through a contact device at a constant speed. Due to the large distances, the telegraph current was weakened by increasing line resistance and insufficient insulation. It was necessary to connect relay stations . The weak current pulse was directed to a sensitive electromagnet, the armature of which operated a contact. This contact closed the circuit of a local battery and gave an amplified pulse to the next station.

economics

The transmission fees were decisive for the long-term profitability of the line. There were already disputes about this shortly after construction began. The fees for a twenty-word telegram lowered the world telegraph congress in the summer of 1868 by 87 ½ francs to 71 francs, that is, to 18.85 percent. The line was no longer profitable and there was a risk of losses. An acceptable result was achieved in renegotiations. The Indo-European Telegraph Company IET made high profits from operating the line from 1886 onwards.

Operation and adjustment of the line

When the contract was signed, Siemens & Halske also secured the maintenance and operation of the line for £ 34,000 annually. As early as July 1870, the submarine cable in the Black Sea failed due to an earthquake and was replaced by a land line. From the beginning of 1871 the line was back in operation. As a result of the Russian-Turkish conflict, the line on the Black Sea coast was destroyed again in May 1877, and this was repaired by the end of August 1877. In 1913, an average of 1,500 telegrams were transmitted on working days. With the exception of 1914 to 1921, due to the First World War and the political turmoil that followed, the telegraph line was fast, safe and profitable. Technical progress - the use of wireless telegraphy - led to the discontinuation of the line in 1931 . The individual sections of the lines became the property of the respective states and were used for domestic telegram traffic.

literature

Web links

Individual evidence

  1. ↑ a b c d The way of electrical engineering. P. 58 ff.
  2. ↑ a b c d e f Siemens. From the workshop to the global company. P. 44 ff.
  3. ↑ Seventy-five years of the Berlin main telegraph office. 1850-1925.
  4. ^ The globalization of telecommunications in the 19th century. Pp. 243/259.
  5. ↑ Halfway around the world in 28 minutes - The construction of the Indo-European telegraph line. Siemens Historical Institute, accessed June 14, 2019 .
  6. ↑ The globalization of telecommunications in the 19th century. P. 296.
  7. ↑ Seventy-five years of the Berlin main telegraph office. 1850-1925 . P. 170.
  8. ↑ In 28 minutes from London to Calcutta. P. 234.