Z codes (fwd)
jeffreyh at HAWAII.EDU
Fri May 8 00:05:25 EDT 1998
Just found this in the deep dark cracks of the email inbox.
---------- Forwarded message ----------
Date: Sun, 28 Sep 1997 20:51:00 -1000
From: Andrew Emmerson <midshires at cix.co.uk>
Subject: Z codes
This article was recently submitted to the Telecomms Heritage Group's
journal (which I edit). Rather than just reprint the section on Z-codes
and frustrate readers, I attach the full text. Hope this doesn't use up
too much bandwidth!
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, in 1859, set up the Standard 92 Code. 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 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 US establishments
The US 1908 Dodge's Manual gives today's definition of 73 best
regards. Other Dodge numbers were 88 love and kisses, 55 lots of
success and 99 get lost (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 1st July 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 120wpm. 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 there were lots of others.
Operating during the 1930s and early 40s, 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 your morse
is good, X100 affirmative, X112 interrogative, X279 what is the
strength of my signal? X496/257 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 US military, it was replaced by the Q code. However,
the odd X code can still is heard from veteran telegraphists even now
but not very often.
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, I am about to jettison fuel; AS5 generally
followed! Even less well known is QGG send the pony by the next
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.
In conclusion, it is sad fact there will be no successor to the Q code; no
longer is the morse code taught to budding telegraphists, except to the
favoured few specialist Aldis lamp operators in the Royal Navy. Data
stream transmissions have displaced morse and taken over everyday
communication such is the march of time.
Acknowledgements: Grateful thanks to Pat Hawker G3VA and
Peter Broom G5DQ, for their help and advice.
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