Morse Code Explained

What is Morse code?

Morse code is a way of writing text with two signals, short and long. Written down they are a dot and a dash, and sent as sound or light they are a short beep and a long beep. Every letter, number and punctuation mark has its own pattern. It needs only an on and off signal, so it can travel over a wire, a radio, a lamp or a tap on a wall.

The chart

Letters

Numbers

Punctuation

Timing

All the timing in Morse code is built on one unit, which is the length of a dot.

Speed is counted in words per minute, using the word PARIS as the standard, which takes 50 units. At 20 words per minute, one unit is 60 milliseconds, so a dot lasts 0.06 seconds. The unit in milliseconds is 1200 divided by the words per minute.

SOS and prosigns

The distress signal SOS is three dots, three dashes and three dots, sent as one unbroken group: ...---... It is not really the letters S, O and S, which is why they are sent without letter gaps. It was chosen because it is easy to send and to recognise. Operators also use prosigns, which are procedural signals sent as one group, such as the error signal of eight dots.

A short history

The code was developed in the 1830s and 1840s for the electric telegraph by Samuel Morse and Alfred Vail. The original American version had different patterns and spacing. A revised International Morse code, the one in the chart above, was agreed in the 1860s for use between countries and is the version used in radio. For a century it was a main way of sending messages over long distances, at sea, in the armed forces and in aviation.

Where it is used now

• Amateur radio, where it is called CW, for continuous wave, is still popular, because Morse signals can be read through noise that would drown out speech.
• Aviation: radio beacons send their identification in Morse code.
• Accessibility: people with limited movement can type with one or two switches using Morse code, and some phone keyboards offer a Morse input mode.
• Puzzles, games, jewelry and messages by light or by tapping.

How to learn Morse code

1. Learn it by sound, not by sight. Memorising dots and dashes on paper makes it slow to read. Hear each letter as a rhythm, such as di-dah for A.
2. Start fast, with long gaps. The Farnsworth method sends each letter at full speed but leaves extra time between letters, so you learn the sound of a letter without counting.
3. Add a few letters at a time. The Koch method starts with two letters at full speed and adds a new one when you can read the set well.
4. Practise a little every day. Ten minutes a day works better than one long session.
5. Check your work. Write what you hear, then check it with the Morse to text decoder.

Handy tools

Use the Morse code translator for both directions, text to Morse to make a message with sound, and Morse to text to read one.