Subject: Z codes (By Andy, G8PTH)

This article was submitted to the Telecomms Heritage Group's journal, which is edited by Andy, G8PTH.

TELEGRAPHIC CODES OF MORSE AND MEN by Kenneth Brown G0PSW

The first line telegraph message is thought to have been sent from Washington to Baltimore in May 1844 by Samuel Finley Breeze Morse (1791-1872). He is said to have tapped out the message, "What hath God wrought?" using a code of interrupted signals which he and his associate Alfred Louis Vail (1807-1859), had developed some years earlier. After this momentous achievement and following the founding of Western Union in 1856, coast to coast telegraph lines were quickly installed and it then became commercially possible to send and receive telegraphic traffic by line.

Since then and with an eye on faster speeds of transmissions and higher accuracy, newspapers, railways and post offices made great use of the telegraph to provide their customers with speedy, economic, personal and commercial communication. This also paved the way for transmitting traffic by radio from the late 1890s following successful experiments by Marconi.

One way of speeding the flow of traffic was to operate an agreed set of short codes to replace well-known sentences or phrases but at that time there was no common national or international standard. The first of many conferences to discuss and try to resolve this issue was held in the US in April 1857, culminating with the release of the National Telegraphic Review and Operators' Guide. This Guide makes the first authentic reference to the well-known greeting 73 (at that time meaning love and kisses). Later editions kept this definition, but as time went by, the meaning of 73 changed from a Valentine type of greeting to a vague sign of operators' fraternalism.

Western Union set up the Standard 92 Code in 1859. Replacing common sentences and phrases with selected numbers between 1 and 92, the message was telegraphed to a distant station. At the distant end the numbers were decoded and a plain language version delivered to the recipient. The definition of 73 changed yet again to a very flowery "accept my compliments". From 1859 to 1900 the many telegraphic manuals show variations of this meaning. Each major telegraph and railway company had its own distinctive telegraphic codes. Since there was no agreed standard, all were different, and as a consequence, there was much confusion in communicating with different networks. During this time there were even two alphabetical Morse codes; the American and the Continental (European) versions. Although there were basic similarities, there were also some major differences. This, combined with the multiplicity of telegraphic codes, caused confusion and made communication with and between U.S. establishments particularly difficult.

The U.S. 1908 Dodge's Manual gives today's definition of 73 as "best regards". Other Dodge numbers were 88 (love and kisses), 55 (lots of success), and 99 (get lost, which was probably unofficial).

Also, in 1908, the British Post Office, despairing of action to agree an international code of abbreviations, issued its own list of two letter abbreviations intended for use between British coast stations and ships. The list, published in the PMG's Instructions to Wireless Telegraphists, included abbreviations RA to RZ and SA to SF. The next International Radiotelegraphic Convention, held in London in July 1912, adopted and extended the GPO abbreviations. "Q" was added as the first letter and so the "Q" code was born. The new code now ran from QRA to QRZ and QSA to QSX. On July 1st, 1913, the Q code finally became an official international information code, updated as changing circumstances demanded to include new codes relating to such matters as aviation and maritime.

Some time later came the Z code, running in parallel with the Q code. This originated as a company code of cable and wireless with application limited, in the main, to high speeds machine Morse operating at speeds of typically 120 wpm. Widely used by many countries, including Germany, the Q code and Z code continued in use throughout the war. After the war, high-speed Morse became less widely used and was replaced by other forms of traffic communication such as RTTY and facsimile. The Z code, therefore, gradually went out of fashion and slowly disappeared. Examples of the Z code include ZAA (you are not observing circuit discipline), ZAN (we can receive absolutely nothing), ZST (send slips twice), ZAP (acknowledge please), and several others.

Operating during the 1930s and early 1940s, at the same time as the Z and Q codes, was the X code, then in use by European military services as a wireless telegraphy code. This consisted of the letter X followed by a number. For example; X34 meant "your Morse is bad", X50 meant "your Morse is good", X100 meant "affirmative", X112 meant "interrogative", X279 meant "what is the strength of my signal?" and X496/257 meant "I am winding in my aerial prior to landing/I have nothing further for you".

The X code continued in use with the forces until 1942 when, at the insistence of the U.S. military, it was replaced by the Q code.

So the Q code became the standard international military and civil telegraphic letter code used in CW communication (sometimes, incorrectly, even in R/T). Published as an operators' manual, there are separate sections available to deal with various areas of communication. Some less well known examples of the Q code used by base stations of the British army included QAU followed by QHU, meaning "I am waterlogged" and "I am about to jettison fuel" (AS5 generally followed). Even less well known is QGG, meaning "send the pony by the next train".

Widely used by radio amateurs operating CW, today's Q code has slightly different meanings but is still very similar to the 1912 version. One of the great benefits of using the Q code is the pleasure in being able to communicate with overseas operators who may not be fluent in the English language.