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The Morse alphabet and timing
Dits, dahs and spacing.
Dits, dahs and spacing.
Morse code is made of two signals: a short dit and a long dah, three times as long. What makes it readable is the silence between them. Everything is a multiple of one dit:
| Part | Length |
|---|---|
| dit (·) | 1 unit |
| dah (−) | 3 units |
| gap between dits and dahs inside a letter | 1 unit |
| gap between letters | 3 units |
| gap between words | 7 units |
Speed is measured in words per minute (WPM), using the word PARIS as the yardstick: it takes exactly 50 units to send. So one unit lasts 1.2 ÷ WPM seconds, which is 60 ms at 20 WPM.
Common letters get short codes: E is a single dit and T a single dah.
| Letter | Code | Letter | Code | Letter | Code |
|---|---|---|---|---|---|
| A | · − | J | · − − − | S | · · · |
| B | − · · · | K | − · − | T | − |
| C | − · − · | L | · − · · | U | · · − |
| D | − · · | M | − − | V | · · · − |
| E | · | N | − · | W | · − − |
| F | · · − · | O | − − − | X | − · · − |
| G | − − · | P | · − − · | Y | − · − − |
| H | · · · · | Q | − − · − | Z | − − · · |
| I | · · | R | · − · |
Numbers follow a pattern, so they are easy to learn: 1 to 5 start with that many dits and fill the rest with dahs; 6 to 9 start with that many (minus five) dahs and fill the rest with dits; 0 is five dahs.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 0 |
|---|---|---|---|---|---|---|---|---|---|
| · − − − − | · · − − − | · · · − − | · · · · − | · · · · · | − · · · · | − − · · · | − − − · · | − − − − · | − − − − − |
Common punctuation: period · − · − · − , comma − − · · − − , question mark · · − − · · , slash − · · − ·
Don't memorise dots and dashes on paper. Operators hear each letter as a short rhythm, like a word, never counting elements. That is why Morse is taught by sound at a fast character speed. See Learning Morse code.