CQD (transmitted in Morse code as ▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄) is one of the first distress signals adopted for radio use. On January 7, 1904 the Marconi International Marine Communication Company issued "Circular 57", which specified that, for the company's installations, beginning February 1, 1904 "the call to be given by ships in distress or in any way requiring assistance shall be 'C.Q.D.'".
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 first 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" because if gaps are inserted it can be thought of as the Morse codes for those letters – by contrast CQD is transmitted as three distinct letters with a short gap between each. Germany had first adopted this distress signal in regulations effective 1 April 1905.)
Between 1899 and 1908, nine documented rescues were made by the use of wireless. The earliest of these was a distress call from the East Goodwin lightship. However, for the earliest of these, there was no standardized distress signal. The first US ship to send a wireless distress call in 1905 simply sent HELP (in both International Morse and American Morse). By February 1904, the Marconi Wireless Company required all its operators to use CQD for a ship in distress or for requiring URGENT assistance. In the early morning of 23 January 1909, whilst sailing into New York from Liverpool, RMS Republic collided with the Italian liner SS Florida in fog off the island of Nantucket, Massachusetts, United States. Radio Operator Jack Binns sent the CQD distress signal by wireless transmission.
On April 15, 1912, RMS Titanic radio operator Jack Phillips initially sent "CQD", which was still commonly used by British ships. Harold Bride, the junior radio operator, suggested using "SOS", saying half-jokingly that it might be his last chance to use the new code. Phillips thereafter began to alternate between the two. Though Bride survived the sinking, Phillips did not.
- 500 kHz (Morse distress frequency)
- 2182 kHz (voice distress frequency)
- Distress signal
- Global Maritime Distress Safety System
- Prosigns for Morse code
- "Distress Signalling" by G. E. Turnbull, The Year-book of Wireless Telegraphy and Telephony, 1913 edition, pages 318-322.
- Le Robert & Collins Senior (2002), Dictionnaire français-anglais, anglais-français, Paris: Dictionnaires Le Robert-VUEF. re: sécurité : e.g. des mesures de sécurité, "safety measures, precautions, or alerts"
- Campbell, p. 218
- Service Regulation XVI, 1906 International Wireless Telegraph Convention, U.S. Government Printing Office, page 38.
- "Regelung der Funkentelegraphie im Deutschen Reich". Elektrotechnische Zeitschrift, 27 April 1905, pages 413–414.
- "German Regulations for the Control of Spark Telegraphy", The Electrician, 5 May 1905, pages 94–95.
- "C Q D" by Alfred M. Caddell, Radio Broadcast, April 1924, pages 449–455.
- Jack Binns: Hero (JackBinns.org).
- Campbell (2008: 1911)
- "Thrilling story by Titanic's surviving wireless man". 19 April 1912. Retrieved 29 September 2018.
- Stephan Dubreuil, Come Quick, Danger: A History of Marine Radio in Canada, Ottawa: Fisheries and Oceans Canada, Coast Guard, 1998. OCLC 39748172.
- Pete Caesar, SOS ... CQD: Four Ships in Trouble, Muskegon, Mich.: Marine Press, 1977. OCLC 3182026.
- Ballard C. Campbell,Disasters, Accidents, and Crises in American History, Infobase Publishing, 2008 ISBN 1438130120.