Subsequent to our informative discussion of the origins of CQ last year, I discovered an earlier instance, from Latimer Clark and Robert Sabine, "Electrical Tables and Formulæ: For Use of Telegraph Inspectors and Operators" published in London in 1871.

https://books.google.com/books?id=YgQ_AAAAYAAJ&pg=PA243
'The call for "all stations" (C  Q) is the letter s ---   ---   --- &c, given during one minute.' 

I have now added this to the Wikipedia entry:
https://en.wikipedia.org/wiki/CQ_(call)#History_and_usage

However, CQ appears to date back even further. In the August 1st 1884 issue of the trade paper The Telegraphist, an article by "Old Electric" on Ocean Telegraphy mentioned that the author joined the telegraph service in 1852, so was speaking from personal experience, and included this note as part of a description of the adoption of International Morse in Britain in 1851:

 https://books.google.com/books?id=n65bAAAAQAAJ&pg=PA110&dq=%22cq%22

"The alphabet for Bain's printing was not like the one now in use for Morse. When the Electric Telegraph Company agreed to adopt the international alphabet, notice was given to CQ (all stations) to prepare for the change, and from a fixed date to abandon the one and adopt the other."

Although this was published in 1884 and reflects memories from 32 years earlier, I have no reason to doubt its accuracy. Encyclopedia Britannica confirms that "the International Morse Code was adopted in 1851 for use on cables, for land telegraph lines except in North America, and later for wireless telegraphy.", but I have yet to find any publication from the early 1850s which specifically mentions CQ.

Although this is not rigorous enough for Wikipedia, the two-letter codes, almost certainly including CQ, were devised by Francis Whishaw, who managed the message department of the Electric Telegraph Company from 1845 to 1848.

In 1846 he created a matrix of codes, with the letters of the alphabet from top to bottom of the first column, and left to right of the top row.  At each intersection he placed a station name or operation code, so for example, the ETC's main premises at Lothbury in London had the code IK, and "End of Message" was PQ.  These are actual examples listed in articles about Whishaw's invention published at the time - tantalizingly, DQ is "Message Follows", PQ is "End of Message", and RQ is "Query # of Words" but CQ is not mentioned in a column of what are obviously service codes rather than station names.

Of the 26 x 26 matrix, which could have a possible 676 entries, only a very small number are given as examples. What is needed is Whishaw's original documentation from 1846, which would presumably have his complete list.

If you want to read more about the ETC and its codes, there is detailed information on my late friend and fellow-researcher Steve Roberts' Distant Writing website:
https://distantwriting.co.uk/howthecompaniesworked.html
(scroll down to Early Codes) 

Bill B.

On 10-Sep-23 11:09 PM, David J. J. Ring, Jr. wrote:

      

      

      
      

        
I've updated
          the Wikipedia Entry on "CQ" giving citations for long
          established facts.

        


        

        
I thank Bill
          Burns of https://atlantic-cable.com/
          a longtime historian and members of the Antique Wireless Association, Society of
            Wireless Pioneers, and Veteran Wireless Operators
            Association for their continued assistance and supplied
          resources to make these needed corrections.

        


        

        

          

            
From Wikipedia,
              the free encyclopedia

          

          

            

              
For
                other uses, see CQ (disambiguation).

              0:05CQ
              call of German amateur radio station DG2RBH on the 80 m
              band ("Hello CQ from Delta Golf 2 Romeo Bravo Hotel")
              
CQ is a station code
                used by wireless operators derived
                from long established telegraphic practice on undersea
                cables and landlines, particularly used by those
                communicating in Morse code, (  ▄▄▄ ▄ ▄▄▄ ▄   ▄▄▄ ▄▄▄ ▄ ▄▄▄ ),
                but also by voice operators, to make a general call
                (called a CQ call). Transmitting the letters CQ on
                a particular radio frequency means that the
                transmission is an broadcast or "General Call" to anyone
                listening, and when the operator sends "K' or says "Go
                Ahead" it is an invitation for any licensed amateur
                radio operators listening on that frequency to respond.
                It is widely used in amateur radio.[1]

              
History
                  and usage[edit]

              
The CQ station code was[2] originally used
                by landline and undersea cable telegraphy operators in
                the United Kingdom. The oldest
                reference found to the station code CQ is contained in
                The Telegraphist. Edited by W. Lynd, Volume 1 1886. [3] which states on
                p. 15 under "Alphabetical Codes and Abbreviations": "CQ
                All Stations". Additionally, the telegraphic station
                code "CQ" was mentioned in "The Telegraphist. Edited by
                W. Lynd, Volume 1 1886" [4]

              0:08Demonstration
              of the spark-gap transmitter at Massie Wireless Station sending
              Morse code ("CQ DE PJ")
              
CQ was adopted by the Marconi Company in 1904 for
                use in wireless telegraphy by spark-gap transmitter, and
                was adopted internationally at the 1912 London International
                  Radiotelegraph Convention, and is still used.[5]