Can you tap morse code?
Yes, though the standard says nothing about how. ITU-R M.1677-1 fixes the timing of the signal, not the way you make it, so a tapped message works as long as it keeps the same ratio: one count for a dit, three for a dah, one count of silence inside a letter and three between letters.
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HI is four dits, a letter gap, then two dits. Play it and tap along on the table to feel where the gaps fall.
What the standard actually fixes
Morse is a set of lengths, not a set of noises. ITU-R M.1677-1 says a dah is three times a dit, that marks inside a character are one unit apart, that characters are three units apart and words seven. It says nothing about tones, lamps or fingers.
So tapping is allowed in the only sense that matters: if your taps carry those ratios, you are sending morse. If they do not, you are sending something else that happens to use dots and dashes.
The problem with a tap
A struck tap has no length. It is an instant, so it cannot be one unit long in one place and three units long in another, and that is the one thing morse needs. There are two ways round it:
- Press or scrape. Keep your finger or a coin in contact with the surface for the length of the mark. One count for a dit, three for a dah. This is closest to a real key and it is what a pipe or a table edge is good for.
- Use the silence instead. If you can only strike, keep every strike the same and put the length into the gap that follows it: one count after a dit, three after a dah, and a longer wait at the end of a letter. It is slower and easier to miscount, so decide which method you are using before you start and stay with it.
It is not the tap code
The knocking code that turns up in accounts of prisoners communicating through walls is a different system. The Naval History and Heritage Command’s account of American prisoners in Vietnam describes men who were forbidden to speak communicating by knocking, tapping a tin cup or coughing a set number of times for each letter of the alphabet.
That is the opposite of how morse works. The tap code counts; morse measures time. A code built on counting is the sensible choice against a concrete wall, where there is no way to make one knock last three times as long as another, and neither system will decode the other.
Getting the beat
Play HI above at 5 words per minute (WPM) and tap along with it. Four dits, a gap of three counts, then two dits. The gap is the part people lose first, and hearing it a few times fixes it faster than reading about it.
Once the rhythm is there, type a word of your own into the morse code translator and try it. On a phone, the SOS page will vibrate the handset in time with each mark, which is the same code again, delivered by touch.
Questions people ask next
How do you tap a dah?
Hold the tap for three counts if you are pressing or scraping a surface. If you can only strike it, leave three counts of silence after the strike instead and keep that rule for the whole message.
Is tapping morse code the same as the tap code?
No. The code American prisoners used in Vietnam counted a set number of knocks for each letter, so it carries no dits or dahs and no morse timing at all.
What should I tap on?
Anything that lets you vary the length of the sound. A pipe, a table edge or a wall works for pressing and scraping; a hard strike gives you no length to work with.
How fast can you tap morse code?
Slower than you can key it, because the counts have to stay even by hand. Starting at 5 words per minute is realistic, and even that takes practice.
Can a phone vibrate morse code?
Yes. Our SOS page and phrase pages can vibrate an Android phone in time with the marks, which is the same signal delivered by touch instead of sound.
Related answers
- How do you send morse code by blinking?
By holding each blink for the length of its mark.
- What does morse code sound like?
Like a single steady tone switched on and off.
- Does morse code have spaces?
Yes, three of them, and they carry as much as the marks do.
Sources
- Codes and timing follow Recommendation ITU-R M.1677-1 (10/2009), International Morse code (International Telecommunication Union, 2009).
- Prisoners of war, Vietnam exhibit, Hampton Roads Naval Museum (Naval History and Heritage Command).