Can Morse Code actually be transmitted by knocking as is shown in several movies?

Answer 1

Of course. Since Morse Code is just a series of long and short signals, you could knock at irregular intervals. Think of knocking out the rhythm of a song and you would see what I mean. Or SOS, like this: SOS = (knockknockknock knock--knock--knock---knockknockknock) Morse Code depends on the signal (knock) itself varying in duration. The pause after the knock has its own significance, separating letters, words, or sentences, depending on the length of the pause. The pauses in between the knocks would be interpreted as character breaks. Instead of three dashes, the "knock--knock--knock" in the middle of your SOS example would be received as three separate one-dot characters. A single dot represents E in Morse Code. Thus, your SOS message becomes "SEEES".