SOS in Morse Code
SOS is the most famous signal in Morse code: ... --- ... — three dots, three dashes, three dots, sent as one unbroken sequence. Press Play below to hear and see it. Turn up your volume — the demo also flashes the screen in time with the signal.
Why SOS was chosen
When wireless telegraphy spread across ships in the early 1900s, the world needed one distress call that any operator, in any country, could send and recognise instantly. SOS won out because its pattern is uniquely clear: di-di-dit dah-dah-dah di-di-dit, transmitted with no spaces between the letters so it reads as a single, rhythmic, unmistakable burst. It is symmetrical, easy to send under stress, and almost impossible to confuse with ordinary message traffic.
Crucially, SOS does not stand for anything. "Save Our Souls" and "Save Our Ship" are memorable backronyms invented afterwards. The signal was selected for the sound of its code, not the meaning of its letters. It was agreed internationally in 1906 and took effect in 1908, replacing the older "CQD" call.
How to signal SOS in an emergency
The power of SOS is that you can send the rhythm with almost anything:
- Light: three short flashes, three long, three short, using a torch, phone screen, or signal mirror.
- Sound: three short blasts, three long, three short, on a whistle or horn.
- Tapping: the same short-long-short pattern knocked on a pipe, hull, or wall.
After each SOS, pause for a few seconds, then repeat. Rescuers listening or watching for a pattern will pick out the deliberate, regular rhythm far more easily than random noise.
Practise and explore
To send other messages, open the main translator and turn on the Light and Vibrate toggles. To understand the dots and dashes behind SOS, read what Morse code is or browse the alphabet.
Frequently asked questions
What is SOS in Morse code?
SOS is three dots, three dashes, three dots: ... --- ... — sent as one continuous signal with no gaps between the letters. It is the internationally recognised distress call.
Does SOS stand for anything?
No. Despite popular backronyms like "Save Our Souls" or "Save Our Ship", SOS does not stand for anything. It was chosen purely because its Morse pattern — di-di-dit dah-dah-dah di-di-dit — is simple, unmistakable, and hard to confuse with anything else.
How do I signal SOS without a radio?
Send the rhythm any way you can: three short flashes of a torch, three long, three short; three short whistle blasts, three long, three short; or three short taps, three long, three short on a hard surface. Pause, then repeat.
When was SOS adopted?
SOS was adopted as the international distress signal at a radiotelegraph conference in 1906 and came into force in 1908, replacing earlier signals such as the British "CQD".
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