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SOS in Morse code and how to signal it with a flashlight

SOS is the international Morse code distress signal: ···−−−··· (three dots, three dashes, three dots), sent as one continuous pattern with no gaps between the letters. It was adopted at the 1906 International Radiotelegraph Convention in Berlin and came into use in 1908. It is often said to mean "Save Our Souls", but it was chosen because the rhythm is easy to send and impossible to mistake.

Signaling SOS with a flashlight

Count "one" for each unit and it gets easy.

  • 1. Three short: on for 1 unit, off for 1, three times
  • 2. Three long: on for 3 units, off for 1, three times
  • 3. Three short: on for 1 unit, off for 1, three times
  • 4. Pause for 7 units or more, then repeat

How long one SOS takes

One dot lasts 1200 ÷ WPM milliseconds. For light signals, slower is better for someone watching from far away.

SpeedDot lengthOne SOSWith repeat gap
5 WPM240 msabout 5.5 sabout 7.2 s
10 WPM120 msabout 2.8 sabout 3.6 s
20 WPM60 msabout 1.4 sabout 1.8 s

In a real emergency

If your phone has signal, call 911, 112 or your local emergency number first. Light signals carry farthest in the dark from open ground, and three of anything (flashes, whistle blasts, fires) is a widely recognized distress signal. A flashlight drains the battery fast, so rest between repeats.

In Morsely

Play any message through the flashlight, full-screen flashes, sound or vibration. The SOS button on the home screen widget opens the app and flashes SOS right away. A short photosensitivity notice appears before flashing lights play.

FAQ

What is SOS in Morse code?
···−−−···. S (···), O (−−−), S (···) sent back to back with no gaps between the letters.
If you're having an emergency and you need to know Morse code, is SOS enough?
For calling for help, SOS is all you need. If your phone has signal, call emergency services first.
Does SOS stand for Save Our Souls?
No. It was picked for its easy rhythm; the phrase came later.
Can I send SOS with my phone's flashlight?
Yes. Short is 1 unit on, long is 3 units on. Morsely plays it automatically through the flashlight or the screen.

One tap on the widget flashes SOS

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