It did not become possible to encrypt voice communications in practical ways in the field until well after WWII (during WWII, the state of the art was SIGSALY - a SIGSALY terminal weighed about 50 tonnes).

As the equipment became cheaper and more portable, it was able to displace encrypted Morse code communications.

Morse also began to be replaced by various forms of telegraphic data communication that were being developed, and provided much higher transmission rates.

Two questions:

  • What was the last conflict in which Morse was used extensively?

  • Which contexts continued to use Morse the longest? (I'd guess, aviation and espionage, where portability and size are factors.)

(According to Wikipedia, "As of 2015, the United States Air Force still trains ten people a year in Morse." I wonder how much they use it.)

  • WW2: en.wikipedia.org/wiki/M-209
    – Tomas By
    Jul 2, 2022 at 23:15
  • 2
    "nternational Morse Code was used in World War II and in the Korean and Vietnam wars. It was used heavily by the shipping industry and for the safety of the seas up until the early 1990s." (EB)
    – Tomas By
    Jul 2, 2022 at 23:19
  • 1
    The Cold War, and a bit past that. I was still trained in hearing Morse code in the German army, 1992. AFAIK, they stopped the program shortly afterwards.
    – DevSolar
    Jul 3, 2022 at 14:03
  • 1
    In the 90's I used to hang out with a bunch of enlisted who would all get a vacant look on their face when the dot matrix printer started. One of them finally admitted that they had a reflexive reaction to try to decode the Morse code.... and it took a second to realize that the dot matrix printer head was not in fact producing dots and dashes.
    – MCW
    Jul 3, 2022 at 16:29
  • 1
    @MCW -well, it was producing dots… But Morse isn’t needed for a ham license in the US anymore, although many folks still use it. Of course, a computer does fine sending and receiving it.
    – Jon Custer
    Jul 3, 2022 at 22:12


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