Concept

CQD

Summary
CQD (transmitted in Morse code as ) is one of the first distress signals adopted for radio use. On 7 January 1904 the Marconi International Marine Communication Company issued "Circular 57", which specified that, for the company's installations, beginning 1 February 1904 "the call to be given by ships in distress or in any way requiring assistance shall be 'C Q D' ". Background Land telegraphs had adopted the convention of using "CQ" ("sécu", from the French word sécurité) to identify alert, or precautionary messages of interest to all stations along a telegraph line. CQ had then been adopted in maritime radiotelegraphy as a "general call" to any ship or land station. In landline use there was no general emergency signal, so the Marconi company added a "D" ("distress") to CQ in order to create a distress call. Sending "D" was already used internationally to indicate an urgent message. Thus, "CQD" was understood by wireless operators to mean All
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