S in Morse Code: ···
The letter S in Morse code is ···, spoken as "di-di-dit": three short. That is 3 dots, with a dash held three times as long as a dot. To remember it, think si-si-si (three quick beats).
Timing: how long each part lasts
Morse timing is built from one unit, the length of a dot. A dash is 3 units, and the silence between the elements of a single character is 1 unit. At 20 words per minute, one unit is 60 ms, so S breaks down like this:
| Element | Signal | Length (units) | At 20 WPM |
|---|---|---|---|
| Dot | · | 1 | 60 ms |
| Gap | (silence) | 1 | 60 ms |
| Dot | · | 1 | 60 ms |
| Gap | (silence) | 1 | 60 ms |
| Dot | · | 1 | 60 ms |
| Total for S | 5 | 300 ms | |
How to signal S
- Tap it: three short. A short is a quick tap; a long is a heavier tap, or a quick tap followed by a slight hold, about three times as long.
- Blink it: three short. Use quick blinks for dots and slow, deliberate eye closes for dashes, keeping the rhythm steady.
- Flash it: three short. Short flashes for dots; for dashes, hold the light on about three times longer. Any flashlight or phone screen works.
How to remember S
Say si-si-si (three quick beats) in rhythm with the code and the pattern sticks: "di-di-dit".
Words that start with S: Sierra ··· ·· · ·−· ·−· ·−, salt ··· ·− ·−·· −, signal ··· ·· −−· −· ·− ·−··, star ··· − ·− ·−·. The first is S's NATO phonetic name, which operators use to spell aloud.
S is one half of SOS. Three dots, three dashes, three dots was adopted in 1906 precisely because S and O together make a rhythm nothing else sounds like.