Original Morse telegraph was not done by tones. The sounder emitted two clicks, subtlety different, for each key down/up event. So, a dit would be two clicks

Original Morse telegraph was not done by tones. The sounder emitted two clicks, subtlety different, for each key down/up event. So, a dit would be two clicks with a short interval, while a dah would be two clicks with a longer (3x?) interval.