 At the first International Radiotelegraphic Convention, held in Berlin in 1906, Germany's "" distress signal of three-dots three-dashes three-dots () was adopted as the international Morse code distress signal.This distress signal soon became known as "SOS" because it has the same dash-dot sequence as the letters S O S with the gaps between the letters removed, and in fact it is properly written , with an overbar, to distinguish it from the three individual letters.In contrast, CQD is transmitted as three distinct letters with a short gap between each, like regular text.