SOS (emergency signal)

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An emergency telephone marked "SOS"

SOS is an emergency signal that has been used since 1906 as the international Morse code  · · · - - - · · ·  or as a written sequence of letters to request help in an emergency. In the latter case, the letters are written in large format in the sand or snow, in the hope that crews of planes or helicopters will see them and send help. In addition to emergency telephones identified by the letters "SOS".

SOS as Morse code

Morse code of the SOS signal
SOS signal

The code SOS , three short, three long, three short  · · · - - · · ·  (also pronounced as dididit dahdahdah dididit ) is not sent as three single letters, as is often assumed, but without pauses between these letters (i.e. not  · · · - - - · · ·  ). Like any initial transmission or unanswered transmission, the call - here SOS  - must be sent three times in a row (i.e.  · · · - - - · · · · · - - · · · · · · - - - · · ·  ) in order to occupy the transmission frequency longer and thus increase the probability that the code will be recognized accordingly.

history

In April 1904, the Morse Code  · · · - - · · ·  was introduced to the German Imperial Navy as an emergency signal; With effect from April 1, 1905, it was also prescribed for public ship radio in Germany. This conspicuous Morse Code group was intended as an emergency signal to interrupt radio communication and, like a siren, was intended to call all other radio stations to radio silence . It was therefore not to be sent as a call, but to be repeated until all other stations had stopped transmitting. This should be followed by the content of the emergency call.

Internationally, the Marconi Company had determined the code CQD for its radio operators to initiate emergency calls from 1904 . It is made up of the code CQ for French sécurité (here: “Attention!”) ​​And D for détresse (“Emergency”). According to other sources, CQ stood for English come quick (“come quickly”) and D for Danger (“danger”). This signal was not suitable for interrupting calls from other radio stations, but served as a call with the address: To all, emergency call when there was silence.

At that time, the radio system manufacturers and duopolists Marconi and Telefunken competed so fiercely that ship radio operators - at that time not employees of the shipping company , but always of the radio company - were not allowed to accept calls from radio stations of the competition. This could lead to non-compliance with emergency calls. In order to end this illegal state of affairs, it was decided at the international radio conference in Berlin on October 3, 1906 to adopt the German emergency signal internationally; it was officially introduced on July 1, 1908, following confirmation by all seafaring nations. The German emergency signal was memorable and easy to hear from other signals, even for inexperienced radio operators, but it was only slowly taking hold. The first known distress call, issued by the Republic on January 23, 1909 , was CQD, and the Titanic's first radio operator was only informed of the new signal by his colleague in 1912.

Alleged meanings of SOS as an abbreviation for save our souls or save our ship (“Save our souls” or “Save our ship”) were only later interpreted into the signal .

For the first time SOS on 10 June 1909 by the passenger ship RMS Slavonia sent than before the Azores shipwreck suffered. The sinking of the Titanic later showed that in addition to a uniform signal and a standard emergency call frequency, regular monitoring of this frequency was also necessary. The fact that a ship did not provide assistance in the immediate vicinity was due, among other things, to the fact that its on-board radio station was not manned at the time of the accident - there were no regulations for this at the time. It was only after this incident that the mandatory "listening watch" was introduced around the clock in 1912 and the three-minute radio silence on the 500 kHz call and emergency frequency (from the 15th and 45th minute after the full hour). With the later introduction of voice radio , the code word “ Mayday ” and corresponding rules for emergency frequency and radio silence were also agreed for emergency calls .

During the Second World War , additional codes were introduced by the Allies to differentiate between the types of threat in the event of attacks on merchant ships; an RRR call denoted an attack by a surface ship, SSS stood for a submarine attack.

With the global introduction of the satellite-based distress radio system GMDSS in 1999, the Morse code SOS was finally abolished in commercial shipping.

See also

Web links

Wiktionary: SOS  - explanations of meanings, word origins, synonyms, translations
Commons : SOS  - collection of pictures, videos and audio files

Individual evidence

  1. ↑ Huge SOS saves the lives of five people. Welt (TV station) , April 24, 2014, accessed July 8, 2019 .
  2. ↑ Micronesia: "SOS" in the sand saves the lives of two stranded people. Der Spiegel , August 27, 2016, accessed on August 28, 2016 .
  3. ↑ Found intact after almost two days. Tages-Anzeiger , March 6, 2016, accessed on August 28, 2016 .
  4. ^ Regulations for the use of spark telegraphy in public transport, Official Gazette of the Reichs-Postamt, Berlin, March 30, 1905.
  5. ↑ Alexandra Eul: 100 years of SOS: three short, three long ... In: Der Spiegel, one day , July 2, 2008, online at Spiegel.de, accessed on January 26, 2017.
  6. ↑ Peter Kleinort: SOS: First Morse 105 years ago. In: Daily port report of June 10, 2014, p. 16.
  7. ↑ Bernd Januschke, Karl-Friedrich Warner: 1900–1909. The new century. In: Chronicle of the 20th Century. 1983, p. 96.
  8. ^ Ralf Klee and Broder-Jürgen Trede: Morse code up to the downfall. In: one day . January 23, 2009, accessed October 3, 2016 .
  9. ↑ Mirko Smiljanic : Short - long - short or: The power of the signal tone. Deutschlandfunk, September 11, 2015, accessed on October 3, 2016 .
  10. ^ Nigel West: Historical Dictionary of Naval Intelligence . 1st edition. Scarecrow Press, Plymouth 2010, ISBN 978-0-8108-6760-4 . , P. 266.
  11. ↑ Antke Reemts from the German Society for the Rescue of Shipwrecked People (DGzRS)