What does SOS mean?

 By B Sumangal; Illustration by Sudheer Nath

Recently, sailors on the nuclear submarine that sank in the Baltic Sea were isolated from rescue workers as their radio set got damaged. Luckily their radio operators knew the Morse code and were able to communicate by knocking on the sides of the ship.

There are many explanations for what the words stand for: Save Our Souls; Save Our Ship; Send Our Succour… The meaning of all three is the same - it is a plea for help by someone in distress. That's exactly what SOS is.
It is a coded signal for help that continues to be used by ships, planes and stranded people around the world even 162 years after it was invented by the American Samuel Morse, who invented the first successful telegraph instrument in 1837. The Morse code, as it came to be called, is used to send messages through a telegraph line or the wireless.
SOS is the easiest code to transmit and recognise. The code consists of three dots, three dashes and three dots . . . - - - . . . One can tap it on the telegraph or signal with a torch or even with a flag.
Before the invention of the code, long distance communication consisted of lamp signals from hilltops, smoke signals and shouted messages. In 1787, M Lammond, a Frenchman invented the first telegraph line that could send messages over a distance by means of electricity. Morse developed the first successful telegraph instrument in 1837.
Called a transmitter, the telegraph instrument converts a message into electrical signals. In 1838, Morse also developed a code that consisted of dots and dashes representing alphabets and numbers. These codes were easier to send over the telegraphic line. The dots and dashes travel across the wire and are picked up by a receiving set.
The electric signals move a metal point to print these dots and dashes on a paper tape. The code can be used to read these dots and dashes and translate the message.
In 1843, the United States Congress approved the first telegraph line from Baltimore in Maryland to Washington DC. In 1844, Morse sent the first message "What has God wrought" on this line using this code.
Because of its simplicity the Morse Code continues to be used even as mobile wireless telephones are replacing telegraph transmission.