Tapping Morse Code on a Wall

Tap, Tap, Tap! The Myth of Sending Morse Code by Tapping on Pipes or Walls

We’ve all seen it in movies and TV shows – the dramatic scene where a prisoner taps on a pipe or wall, attempting to send a secret message in Morse code. It’s an iconic image that has been ingrained in popular culture, but is there any truth to this method? Well, we hate to break it to you, but the answer is a resounding no. Sending Morse Code by tapping on pipes or walls is nothing more than an entertaining myth, albeit one that has captured our imagination for decades. Most people accept that it is possible because they have never tried to actually read Morse Code

Let’s start by examining some of the most memorable examples from the silver screen. In the film “The Great Escape” (1963), prisoners of war employ this technique to communicate and plan their escape. Similarly, in “The Shawshank Redemption” (1994), Andy Dufresne uses it to connect with his fellow inmates. And who could forget “Escape from Alcatraz” (1979), where Clint Eastwood’s character taps his way to freedom? There was also Scotty tapping on the wall in Star Trek 5. These moments are undeniably thrilling, but sadly, they are far from accurate.

The main flaw with this method lies in the inability to distinguish between dots and dashes, the fundamental components of Morse code. In Morse code, a dot represents a short sound or light signal, while a dash represents a longer one. By tapping on a pipe or wall, the resulting sound is essentially the same length each time, making it impossible to differentiate between the two. So, in essence, the message becomes a series of indistinguishable taps, rendering it unreadable. The movie scenario presumes that the audience is not actually going to read the Morse Code. This is a simple message, can you decode it?

Here is what it looks like
Does it make sense yet?

 

How about this?

Now it should start making sense. The dots and dashes can be clearly distinguished. You can see on the table above that this is CQ, which is a commonly used abbreviation for calling any station. In the click form above it could have been a variety of things.

Of course everyone has heard the old telegraph sounders from movies. That is clicks right? There is a difference. If you listen carefully each character is actually a pair of of clicks, one when the key is depressed and another when the key is released. They have a slightly different sound on on attack and release. This is not what is usually shown in the movie scenario of tapping on the wall since it would require two taps for each character. The telegraph was not originally designed to be read by ear, it put the dots and dashes on a strip of paper. The operators learned to “fast read” the characters from so much time listening to it, but this wasn’t easy and could be misread. As communications transitioned to radio a tone replaced the clicks.

Tap Code
1 2 3 4 5
1 A B C/K D E
2 F G H I J
3 L M N O P
4 Q R S T U
5 V W X Y Z

Now, you might be thinking, “Well, what about the tap code? Isn’t that a similar concept?” While it’s true that the tap code, used by prisoners during times of war, involves tapping on a surface, it is an entirely different system. The tap code is based on a grid of letters, where each letter is represented by a combination of two taps. This way, the message can be accurately conveyed, unlike the Morse code myth we discussed earlier. As you can see Tap Code is entirely different from Morse Code

Additionally, even if we were to suspend our disbelief and accept that sending Morse code by tapping on pipes or walls was possible, there are still countless characters and sequences that could easily be confused. A short tap followed by a long tap might be interpreted as “A,” but it might also be interpreted as “I”, “N” or “M.” Such confusion would inevitably lead to miscommunication and potentially disastrous consequences.

Recently there was real-life incident, the Titan submersible accident which started speculation about a banging noise being Morse Code. When the submersible imploded over 3,800 meters below the surface, the resulting sound was heard as a loud bang by the crew of a passing ship. Conspiracy theories quickly emerged suggesting that the bang was Morse code, a desperate attempt for help from the doomed submarine. However, experts dismissed this idea, explaining that the sound was unrelated.

So, the next time you find yourself enthralled by a movie character’s Morse code tapping, remember that it’s purely for dramatic effect. Sending Morse code by tapping on pipes or walls might make for great storytelling, but in reality, it’s about as effective as using smoke signals to send a text message.

Now, you might be thinking, “Well, what about the tap code? Isn’t that a similar concept?” While it’s true that the tap code, used by prisoners during times of war, involves tapping on a surface, it is an entirely different system. The tap code is based on a grid of letters, where each letter is represented by a combination of two taps. This way, the message can be accurately conveyed, unlike the Morse code myth we discussed earlier. As you can see Tap Code is entirely different from Morse Code

Additionally, even if we were to suspend our disbelief and accept that sending Morse code by tapping on pipes or walls was possible, there are still countless characters and sequences that could easily be confused. A short tap followed by a long tap might be interpreted as “A,” but it might also be interpreted as “I”, “N” or “M.” Such confusion would inevitably lead to miscommunication and potentially disastrous consequences.

Recently there was real-life incident, the Titan submersible accident which started speculation about a banging noise being Morse Code. When the submersible imploded over 3,800 meters below the surface, the resulting sound was heard as a loud bang by the crew of a passing ship. Conspiracy theories quickly emerged suggesting that the bang was Morse code, a desperate attempt for help from the doomed submarine. However, experts dismissed this idea, explaining that the sound was unrelated.

So, the next time you find yourself enthralled by a movie character’s Morse code tapping, remember that it’s purely for dramatic effect. Sending Morse code by tapping on pipes or walls might make for great storytelling, but in reality, it’s about as effective as using smoke signals to send a text message.

View Comments

  • When passing morse via taps, the information is conveyed in the length of silences between the taps rather than the taps themselves. You're correct that most movies don't bother to render this correctly but that doesn't mean it's not possible.

      • If you are talking about single taps, you won't be able to frame it up. Just E and T will sound the same. How would you tell the difference between EE and I? I did address the double tap format of the sounding board, there is a message there you can try to decode if you want. One hint, it is in American Morse code, not International Morse code. There are a couple issues. One is that in reading Morse code timing is essential. A dash should be 3 times the length of the dot, there needs to be a distinct space between characters and words. So you start off listening to dots and dashes, then there is something that was 2 times as long as the dot. Was that a dot or a dash? While you are thinking about it, another character comes. What was it? This happens with plain tone, double clicks makes it worse. There are computer programs that will read Morse code, but they are often inaccurate. Some of the reason is noise on the air, but often the reasons is poorly sent code with ambiguous timing.

        The second issue is that sending and receiving code is a learned reflex. You don't have time to look at the table to decode the letters. You have to equate sound to letter. Sending it you have to be able to time the sounds. So, an experiment: Put together a message then see if you can send it using double taps instead of long and short. When you think you have it mastered, record it, then give it to someone else to read. Does your message get through?

        I am not aware of any movie where they used a double tap to form the characters, it is always single tap. The audience accepts that, largely because they have never tried to send or receive Morse Code. In the movie someone always says what the message is, so they imagine that they could hear long and short, but reality is that there are too many characters that would be confused and even at slow speeds trying to apply context would be so much of a distraction that the listener would get out of sync. In the Star Trek example they read the characters off one at a time. Tap Tap Tap, S. Could have been an O at a faster speed, or it could be a U. Tap, T. Could have been an E, how would you know the difference? Tap Tap, A or was it I? Tap Tap, N, or was that TE?

  • A loud tap for da, quieter one for dit.

    Perhaps a shorter way to tap code is send a pair of taps for each letter. EG. E would be long pause - 5 taps - long pause. Z would be long pause - 2 taps - short pause - 6 taps - long pause.

  • As a few said tapping on wall or pipe would just need the psises and go slower. Why wouldn't that work and a ver long pause between words. The machines they use fir Morse code was so fast it lead to errors, so don't think the other is impossible. I was tapping a couple words before I read the comments and instinctively my tap was a long pause.
    Not sure how this article came to the conclusion of impossible as the whole world doesn't have electronic clicking devices and ships used lights and it just showed the light at longer intervals e vans
    I think the need out ways the impossible theory

    • In the simplest form we can take two letters E which is . and T which is -
      So in tapping it, one would be tap, and the other would be tap. Do you see the issue?
      There is no standard time reference in Morse code. You don't know the rate at which it is being sent, and humans always have their timing drift whether sending or receiving.