The original "MORSE CODE" used by Samuel Morse since the 1840's
to allow letters to be sent as short electrical signals (dots)
and long electrical signals (dashes) along with some embedded
spaces was also called the "AMERICAN" MORSE CODE.
It was widely used throughout Europe and America in very early (mid 1800's) land-line communications and has continued to be used to the present in America for this form of Land-Line telegraphic communication in which the signals were carried across the land by lines (wires) supported by telegraph poles.
Land-line communications use "sounders" to allow the receiving operator to "hear" the clicking sounds of the code and to translate them into letters. The early "Morse Code" was well suited for this form of communication but could not easily be used for radio telegraphic communication due to the embedded spaces which were actually an integral part of several letters. For instance, the letter " o " was dot-space-dot in the original Morse Code.
The original "Morse Code" was replaced in England in the 1800's by a
somewhat similar code which eliminated all of the embedded
spaces and long dashes within letters that were found
in many of the letters in the original Morse code. For instance, the
letter " o " became Dash-Dash-Dash.
This new code was called the "CONTINENTAL" or "INTERNATIONAL" MORSE CODE and became the universal standard for Radio Telegraph Communications and for ** European land-line telegraphic communications. It was only in America that the original Morse Code continued to be used by railroad and inter-city land-line telegraph operators well into the 1960's.
Here is a list which shows the dot and dash equivalents of
letters and numbers in the Original Morse code (American Morse Code),
and the Continental (International) code.
An explanation of the timing and length of the characters follows the lists.
( DOT = * DASH = - LONG DASH = ---- ) MORSE CODE CONTINENTAL CODE CHARACTER: AMERICAN MORSE INTERNATIONAL CODE A * - * - B - * * * - * * * C * * * - * - * D - * * - * * E * * F * - * * * - * G - - * - - * H * * * * * * * * I * * * * J - * - * * - - - K - * - - * - L ---- * - * * M - - - - N - * - * O * * - - - P * * * * * * - - * Q * * - * - - * - R * * * * - * S * * * * * * T - - U * * - * * - V * * * - * * * - W * - - * - - X * - * * - * * - Y * * * * - * - - Z * * * * - - * * 1 * - - * * - - - - 2 * * - * * * * - - - 3 * * * - * * * * - - 4 * * * * - * * * * - 5 - - - * * * * * 6 * * * * * * - * * * * 7 - - * * - - * * * 8 - * * * * - - - * * 9 - * * - - - - - * 0 ------ - - - - - Period * * - - * * * - * - * - Comma * - * - - - * * - - Question - * * - * * * - - * *EXPLANATION OF SPACING AND TIMING:
To standardize the International Code Transmission Speed,
the 5-letter word PARIS is used to establish the number of
''words-per-minute''. For example, if the word PARIS was
sent 5 times in a minute, the transmission speed would be
5-words-per-minute or WPM.
The following relationships exist between the elements of
the code (dits and dahs), the characters (letters) and the words:
The DIT is the Basic UNIT of Length.
The DAH is equal in length to three DITS.
The space between the DITS and DAHS within a character (letter) is equal to one DIT.
The space between characters (letters) in a word is equal to three DITS.
The space between words is equal to seven DITS.
(Source: U.S. Army Technical Manual TM-11-459/TO 31-3-16 - Sept. 1957)
SPEED IN WORDS-PER-MINUTE or WPM:
The following information about the calibration of the speed of transmission
in WPM (Words-Per-Minute) was provided by Marshall Emm, N1FN.
There are two standards-- for most practical purposes, and the one that most
hams are familiar with, the speed in WPM is defined as the number of times the
word "PARIS" is sent in one minute with normal 1:3:7 spacing and weighting.
"PARIS" was chosen because it has the right number of dits and dahs to
represent an average word length in Morse.
In fact, though, that is the standard for "plain English text" having a normal
distribution of characters. There is anothere standard word, "CODEX" which is
used where the material being sent consists of code groups, in which longer
letters like J and X will occur as frequently as the short ones like E and T.
I think I have also heard that either "12345" or "67890" can be used where the
traffic is entirely numeric, and I would bet there is yet another standard
"word" for traffic with mixed letters and numbers.
In Europe they measure speed in "signs" or "symbols" per minute, and I don't
know if they have a standard symbol set that they use for calibration. Maybe
someone else on the list can fill on this.
Thomas Roth, DL1CQ writes from Germany:
It's the same over here. We also use PARIS as the standard word. The regular
speed for exams, which took about 15 minutes for sending and receiving each,
used to be 60BPM over here in Germany before they started watering things down.
BPM is "Buchtstaben (letters) Pro Minute". So that corresponded exactly to your
12WPM standard. That is/was for hams only.
To get a radio certificate for the merchant navy you had to send and receive
15 minutes of 90BPM or 18WPM of mixed groups (letters and numbers), and 120BPM
or 24WPM for clear text and all kinds of simulated traffic without
interruption and you were allowed exactly ZERO mistakes on receiving and 3
mistakes on sending.
NOTE: I AM ALWAYS LOOKING TO BUY OR PHOTOGRAPH OR TRADE TELEGRAPH KEYS !
Professor Tom Perera
Montclair State University