From Recommendation ITU-R M.1172 1  ITU-R M.1172F*
MISCELLANEOUS ABBREVIATIONS AND SIGNALS TO BE USED FOR RADIOCOMMUNICATIONS IN THE MARITIME MOBILE SERVICE (1995)

CP General call to two or more specified stations (see Recommendation ITU-R M.1170).

CQ General call to all stations.

File attached. 

It's an excellent document to have around as it has the Q code from QOA to QUZ.

It also has RQ Request, BQ Bequest, and the only abbreviation I have never heard used: 

YZ The words which follow are in plain language.

I wonder if that was used like this:

QSD YZ STOP SENDING WITH YOUR ARSE

Notice the official ITU procedure for using Q codes on radiotelephone. When a question is desired the Q code is vocalized:

QRZ RQ or even QUEBEC ROMEO ZULU ROMEO QUEBEC. 

That might clear up the contest interference on SSB on the amateur bands. 

73 



On Fri, Sep 8, 2023, 3:34 PM Bill Burns <billb@ftldesign.com> wrote:

I agree with David, and the first paragraph of the "History and usage" section of the CQ Wikipedia article that he quotes below, https://en.wikipedia.org/wiki/CQ_(call)
needs a complete rewrite, which I will attack when I have some time. 

The cite for CQ's French origin in that section is to a personal "Ocean Liners" website page on Titanic, which is apparently the source of the postal French nonsense: http://www.oceanliner.org/titanic_radio.htm
That page has no reference for the bogus information it provides, which was then copied to Wikipedia.

Another source linked on Wikipedia is a book on Titanic, which also has almost identical wording to the Ocean Liners page:

I suspect that many of those writing about the Titanic just plagiarize what has gone before!

It's true that the official language of the Universal Postal Union was French after it was established in 1874 by a meeting in Paris, but international agreements on how to handle the mail have absolutely nothing to do with landline or cable telegraphy, nor with radio communications.

The current standard for "Miscellaneous abbreviations and signals to be used for radiocommunications in the maritime mobile service," published by the ITU in 1995, confirms that CQ is (and always has been) "General call to all stations."

Bill