How to communicate covertly with someone else who knows the Tap Code: Tap on the floor, pipe, whistle; make any sound in the following sequence to send an alphabetic message. This code has been around for awhile and was used most notably by US military personnel in the infamous “Hanoi Hilton” prison in North Vietnam. Apparently unknown by their communist captors, Jane Fonda or John Kerry, the code was a significant asset and morale booster..
Above: The entrance to the Hoa Lo Prison in Hanoi. Built by the French in the 1880’s, it is the infamous “Hanoi Hilton” where the communist government guards routinely beat and tortured US military personnel. (Reference 28) et. al.
How does the Tap Code work?
…….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
That’s the letter matrix. Simple, 25 letter grid of our 26 letter alphabet; using C instead of K is the only exception. Any letter can be sent by tapping its matrix coordinates. First tap(s) indicated the ROW NUMBER, second tap(s) indicates the COLUMN NUMBER of the letter to be sent. Example: The letter S would be sent: tap tap tap tap – tap, tap, tap. (Four taps, pause, three taps).
The word CODE tap sequence would be: 1,3 3,4 1,4 1,5.. The word COKE would be tapped 1,3 3,4 1,3 1,5 Your receiver would know the C/K substitution difference by context. You get it….
With practice, it can be memorized and sent-received quickly and efficiently. It could even be sent by flashing a light. US military personnel often sent it while sweeping, tapping the floor with a broom, among other means.
Why not Morse Code? That would require the sending of “taps” with both long and short durations representing dashes and dots. Difficult to do with simple, transient tapping. While knowledge of Morse Code is a basic military skill, few people these days are proficient with it, preferring cell phones and other gadgetry that won’t work when you really need it.
Above: Our buddy demonstrating the use of a broom to send Tap Code messages during our visit of the Hanoi Hilton prison. The potted plant and mat are presumably newer additions. A very sinister place. But that’s a whole other story……
How do you remember the Code? Good old Military Memory mnemonic trick: The first column is AFLQV: Air Force Loves Queer Virgins. No offense – it’s how I was taught it (in the Navy!) – but it’s easy to remember! (The Air Force probably has a different memory trick…see comment below!) Once you’ve got that, the matrix fills itself out as shown. Basic military knowledge – I even taught it to the Cub Scouts. They had lots of practice with it in school. (I recall that I used a different memory trick…) Handy……Of course we use a different system now, but tuck this one away….
Hello,
morse code and this tap code should be teached to every one and/or to the kids in school.
Its helpfull in cases of emergencies. When also the matrix / grid is in mind like the cw code,
someone that is spilled, for example, can “send” a SOS oder more detailed infos.
dididit didididit dididit – not so far away from the real sos and i think also not code inaugurated will be alerted.
73 Juergen
Hi Juergen – Yes, I would agree. Alternate forms of communication can be life-savers and can be generally useful too…I have taught the Tap Code to some young Scouts and they had fun with it (even in school!).
I use Morse Code almost every day and I find it to be effective and fun, plus good for the mind!
73 and thanks for visiting my website..
Hallo Juergen – Ja, ich würde dem zustimmen. Alternative Formen der Kommunikation können Lebensretter sein und kann zu allgemein nützlich sein … Ich habe die Tap -Code , um einige junge Scouts gelehrt und sie hatten Spaß mit ihm (auch in der Schule !).
Ich Morse -Code fast jeden Tag und ich finde es effektiv und macht Spaß , und gut für den Geist zu sein!
73 und vielen Dank für den Besuch meiner Website ..
Tim
N6CC
Yep, the Air Force has a different mnemonic – Air Force Loves Quick Victories.
Matt
Hi Matt – Ha! Touche`
very good!……LOL
If any veterans could add a list of abbreviations, that could save a lot of time for some one who really needs it. Thank you.
Hi Scoobi – Well that would be a lengthy list! The Navy has the Dictionary of Naval Abbreviations for such occasions. AKA the “DICNAVAB” LOL…Really…
The longest, most complex one I have ever seen was posted on a sign at a Navy facility at the Great Lakes naval base:
NAVELECSYSENGCMDMIDWESTDIV. Naval Electronics Systems Engineering Command Mid West Division.
Maybe the usual search engines would be a necessary first step in decoding abbreviations…
Thanks for stopping by…T
Also – the 5 x 7 tap code:
1 2 3 4 5
1 A B C 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
6 1 2 3 4 5
7 6 7 8 9 0
Have not seen that before – looks like it would work – at the expense of brevity however. We were only taught the 5×5 code as above..
Any combination of matrixes can be made to TAP.
Unless people agree in a single tap code (like the “standard” 5×5), there is no real advantage as they can’t decode the message sent. So for that reason let’s stick to the 5×5 tap code no mater of it’s bad thing of no numbers and combination of C/K.
Tap code is the only real saving method of communication, because it does not require people to learn and practice to it. Anyone without radio knowledge can create the 5×5 matrix by just knowing how to place the letters on the matrix and the line/column rule. A child can do it as well as a grandfather. And this is the most powerful feature, it allows communication between experienced and non experienced people, really a life saver.
The other feature is that pulses (in contrast to morse code dots/dashes) can be transmitted by so much more ways than morse code. You can create powerful transmitters by just short circuit the mains power into an LC. Anyone remember the damped waves spark gap? If the world was using tap code, there would be no need for the rotary spark gap, as only single pulses would be sufficient to send a message 🙂 Even pulses of reflected sunlight could be used, I can really not list all the different possibilities where a tap code message would be transmitted.
Hi Kostas- Thanks for the note! Yes, I think the 5×5 matrix was selected for the reasons you state – it is very easy to memorize and use.. Maybe not complete versatility, but the life of pilots is complex enough without the need to also pre-train them in elaborate or clandestine communications techniques. It’s a good thing to know, useful in many situations.
Thanks,Tim