Submarine cables: the key piece that allows modern communications and passes under the seas

Two recent news items have highlighted the importance and global reach of submarine telecommunication cables. First, Tonga’s isolation following a submarine volcanic eruption; second, the fear that Russia will cut submarine cables to cause serious economic and logistical damage to NATO countries.

Large cell phone masts and antennas for satellite signals make us forget that the vast majority of Internet and telecommunications traffic travels through optical fibre wires under land and under sea.

From the telegraph to the sea

The first long-distance communication was achieved with , patented in 1837.

Based on discoveries and inventions started in the 18th century, this device transmits electrical pulses, whose duration and intermittency is controlled at the end of a transmitting wire. At the other end, the receiver translates the combination of pulses into letters, according to a code, such as Morse code.

As soon as it was realized that the telegraph could send messages anywhere the transmitting wire could reach, it began to be thought of how to connect North America with Europe. Naturally,

The great technological problem was the absence of insulating materials that would protect the wires from the water and prevent the electrical pulses from immediately losing charge or short-circuiting. It was Samuel Morse, inventor of the Morse code, who in 1942 tested the first Submarine cable. He used a wire coated with waterproof material:

In the same year, the British experimented with gum from the Southeast Asian gutta-percha tree, which produces a rubber-like latex and turned out to be better insulation for cables.

“At the end of the 19th century, there were already 30 ships exclusively dedicated to laying and maintaining submarine cables.”

Limitations

The first Submarine cable that worked, coated with gutta-percha resin, was installed between England and France in 1849.

The protection and durability of the cables was a constant problem. Apart from cable wear and failure, there were problems with pounding underwater currents and shearing seabeds.

The second major limitation of cables was signal distortion. The longest cables stretched thousands of kilometers and did not have the quality of insulation. In addition to distortion and intrinsic head loss, magnetism could affect transmission. Mechanisms were tried to increase the electrical charge and instruments that made it possible to detect signals with greater precision. Even so, the deterioration of keystrokes limited to a few words per minute per line.

Quickly These were more expensive, but could carry several separate wires, telegraph lines.

In the 1850s there was a rapid expansion of submarine connections in Europe, and in 1858, after four years of work, the Atlantic Telegraph Company placed the first official telegram between two continents: a greeting from Queen Victoria to the president of the United States. The cable worked only three weeks, when a voltage excessive (to achieve greater speed) destroyed it. A second cable, laid in 1865, broke midway and had to be abandoned.

Finally, in 1866, a third cable reached from Foilhomurrum (Ireland) to Newfoundland (now Canada), at the same time that the previous cable was repaired and both entered service. The messages, which until then took two weeks or more, could arrive in two minutes and have an immediate response. At the end of the 19th century, there were already 30 ships exclusively dedicated to laying and maintaining submarine cables.

“The first long-distance communication was achieved with the invention of the telegraph, patented in 1837.”

between continents

The radio, initially patented by Guillermo Marconi in 1896, was used as a wireless telegraph. In less than three years it began to be used for communication between ships and, seeking to compete with the transatlantic cables, in December 1901 achieved successful transmission between Newfoundland and England. Transatlantic radio stations were eventually established for telegraphy and, later, voice transmission.

The telephone, invented at the end of the 19th century, was displacing the telegraph as a means of direct communication, since it could transmit the voice through electrical signals. Unfortunately, the distortion of the signals made their transmission through submarine cables impossible.

Starting in the 1960s, the use of submarine telephone cables faced direct competition from satellites, which use radio signals. The rapid evolution of data compression, transistors, and satellite transmitters almost made radios obsolete. transoceanic cablesuntil a computer revolution took place in the 1980s:

Soon we will explain how fiber optics gave a new impetus to submarine cablesand how the two joined hands for explosive growth with another invention: .

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