ON THIS DAY: 22 November 1906 – The SOS, or International Morse code distress call, became standard worldwide. The SOS Morse code distress signal is represented by the sequence (. . . _ _ _ . . .), which equates to three dots, three dashes, and three dots. Popular belief suggests that SOS stands for ‘Save Our Souls’ or ‘Save Our Ship’, but it simply serves as a distress signal.
Captain Quintino Bonomo, an Italian attending the 1903 Preliminary Conference on Wireless Telegraphy, was the first to suggest the need for a common distress signal at sea. It wasn’t until 1906, at the first International Radio Telegraphic Convention in Berlin, that SOS was officially adopted.
The convention accepted the German ‘SOS’ distress signal, known as the Notzeichen, as the international standard. Germany had been using the three dots, three dashes, and three dots sequence since April 1, 1905. SOS is classified as a ‘procedural sign,’ meaning it is a Morse code shorthand signal requesting urgent assistance. Without this unified approach to international regulations, individual organisations would have been left to determine their own distress signals.
The first ship to use the internationally recognised SOS signal was the Cunard passenger liner RMS Slavonia. Built in 1902, she was en route to New York when she was shipwrecked on June 10, 1909, in the Azores. Although the ship did not survive, all on board were rescued by two passing vessels, the Princess Irene and Batavia, thanks to the SOS call.
As audio radio technology developed, there arose a need for an international spoken distress phrase. In 1927, ‘Mayday,’ derived from the French ‘m’aider,’ meaning ‘help me,’ was adopted by the International Radio Convention. At that time, French was the international language of diplomacy.