What Is Morse Code?

How it works

Each character gets its own sequence. E is one dot, T is one dash, and rarer letters get longer patterns. The full alphabet is on the alphabet page, and you can hear any character there.

What matters as much as the patterns is the timing. Five durations do all the work, and all of them are multiples of one basic unit:

• a dot is one unit, a dash is three
• the gap inside a character is one unit
• the gap between characters is three
• the gap between words is seven

Change the length of that unit and you change the speed without changing anything else. That is why Morse works at four words per minute between two people with torches and at forty between two experienced operators.

Why it is not binary

Morse code is often described as the first binary code. It is a nice line, but it is wrong. A binary code has two symbols of equal weight. Morse has signals of two different lengths and gaps of three different lengths, and the gaps carry as much meaning as the signals - remove them and the message becomes unreadable.

It is closer to a variable-length prefix code, which is what makes it efficient: common letters are short, rare ones are long, and no character is the start of another. That principle turns up again a century later in data compression.

Where Morse code is still used

• Amateur radio. The largest active community by far. A Morse signal occupies a fraction of the bandwidth of speech and can be picked out of noise that would swallow a voice entirely, so it still reaches around the world on very little power.
• Aviation. Navigation beacons identify themselves in Morse. A VOR or NDB station repeats its two or three letter code continuously, and pilots are expected to listen for it to confirm they have tuned the right station. This happens on every instrument flight, today.
• Emergency signaling. A torch, a whistle or a mirror needs no equipment and no shared language. That is why SOS outlived the radio procedure it was written for.
• Accessibility. People with limited movement can type in Morse using two switches, a puff-and-sip tube or even eye blinks. Android has offered a Morse keyboard since 2018, and there are documented cases of people communicating solely by blinking in Morse.

Is it still worth learning?

Nobody needs Morse code the way a ship's operator needed it in 1912. Knowing that, the honest answer is that people learn it for three reasons, and all three hold up.

The first is radio: on the amateur bands, Morse gets through when nothing else does. The second is that it is a genuinely different skill - you are not memorising a table, you are training your ear to hear letters as sounds, and that takes weeks of five-minute sessions rather than one long study. The third is simply that it is a hundred-and-eighty-year-old technology you can still use for real, with a torch, in the dark, with somebody who has learned the same thing.