CQD

CQD (transmitted in Morse code as ▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄) is one of the first distress signals adopted for radio use. It was announced on 7 January 1904, by "Circular 57" of the Marconi International Marine Communication Company, and became effective, beginning 1 February 1904 for Marconi installations.

Land telegraphs had traditionally used "CQ" ("sécu", from the French word sécurité) to identify alert or precautionary messages of interest to all stations along a telegraph line, and CQ had also been adopted as a "general call" for maritime radio use. However, in landline usage there was no general emergency signal, so the Marconi company added a "D" ("distress") to CQ in order to create its distress call. Sending "D" was already used internationally to indicate an urgent message. Thus, "CQD" is understood by wireless operators to mean, "All stations: distress." Contrary to popular belief, CQD does not stand for "Come Quick, Danger", "Come Quickly: Distress", "Come Quick—Drowning!", or "C Q Danger" (Seek You, Danger); these are backronyms.

Although used worldwide by Marconi operators, CQD was never adopted as an international standard, since it could be mistaken for a general call "CQ" if the reception were poor. At the second International Radiotelegraphic Convention, held in Berlin in 1906, Germany's Notzeichen 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". Germany had first adopted this distress signal in regulations effective 1 April 1905.)

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