Most people know that "SOS" is the international distress signal for Morse code but most people do not know what the letters stand for. Some will say it means "SAVE-OUR-SHIP" while others say it means "SAVE-OUR-SOULS" and then there are those who say it only means "SAVE-OH-SAVE." It turns out that all three are wrong.

Guglielmo Marconi is normally credited with inventing the radio but what he actually did was patented a way to communicate with what others had already invented. By turning the radio transmitter on and off Morse code signals could be sent and received.

Morse code, as almost everyone knows, is composed of a series of long and short signals which composes letters and these letters are sent to compose a message. Timing is very important when sending Morse code; a long is three times longer then a short and the space inside a single character (the space between a long and a short, a long and a long, a short and a short, or a short and a long) is the same length as a short. Within a word the space between letters is twice that of a short and the space which shows a word has ended and a new word is beginning is three times that of a short or the same as a long.

Understanding that there is a spacing order is important to understanding the meaning of "SOS." The exact length of the spacing is not important to the understanding of the meaning.

Marconi sent and received his first radio transmission in 1895. By 1904 almost all British ships had radio transmitters and receivers on board. Most of the operators of these radio stations had been telegraphers for the rail road or telegraph office. When there was a message for all stations on a British wire telegraph system the sending operator sent "CQ" meaning all stations. It saved time because he did not have to call each station individually.

It was a natural transition from wire telegraph to wireless telegraph to keep many of the same procedures. "CQ" was no exception so when a radio operator on board a British ship wanted all stations to listen he sent "CQ."

Prior to the installation of wireless telegraph systems on ships if a boat was in distress the only help they could expect was if a ship were in sight and spotted their situation. With the advent of wireless communications assistance could be summoned from over the horizon and beyond visual contact.

When in distress the British operators added the letter "D" to the "CQ" making it "CQD" which distinguished it from a general "CQ." Some people thought it meant "Come Quick Distress" but it really meant "Calling All Stations Distress."

The operators from some other countries used the letters "DDD" to indicate a distress while others used "SOS" to mean distress.

In 1906, at the second Berlin Radiotelegraph Conference the subject of a single international distress signal was approached. There were many hours spent discussing this single subject and finally "SOS" sent as a single character was accepted as the best distress signal.

The reason "SOS" was chosen was because of the distinctive sound of this character. Notice it is not three letters but one single character composed of three shorts, three longs and three shorts all separated by the space of one short. There is no meaning to the three letters, in fact, there are not three letters.

It is amazing how recognizable the sound of "SOS" is. People who do not know Morse code are frequently able to hear and understand "SOS" as meaning someone needs help.

Though accepted in 1906 it was not until 1908 that "SOS" was ratified officially as the international distress call for radio telegraph. Even after 1908 many ships still used "CQD." The radio log of the SS Carpathia showed the RMS Titanic first sent "CQD" after it was struck by an iceberg on the evening of April 14, 1912. After six times of sending the distress call using "CQD" the Titanic's radio operator, Jack Phillips, started interspersing his call with "SOS."

Officially the Morse code character of SOS was dropped as the international maritime distress call on February 1, 1999 and was replaced by the Global Maritime Distress Safety System. "SOS" is still the generally the accepted distress signal for all radio telegraph and signal light transmissions.

Note: Marconi was in New York the day the Titanic sank. He was waiting to sail back to England on the Titanic on her return voyage.