Morse code is an early form of digital communication, however unlike modern binary digital codes that use just two states (commonly represented as 1 and 0), it uses five - dot, dash, short gap (between each letter), medium gap (between words) and long gap (between sentences).
Morse's original code consisted of combinations of dots and dashes that represented numbers. Each number represented a word. This required looking up the number in a book to find the word it represented.
A telegraph key was then used to tap out the sequence of dots and dashes, and pauses that represented the number.
Although Morse invented the telegraph, he lacked technical expertise. He entered an agreement with Alfred Vail who built more practical equipment. Vail developed a system in which each letter or symbol is sent individually, using combinations of dots, dashes, and pauses. Morse and Vail agreed that Vail's method of representing individual symbols would be included in Morse's patent. This system, known American Morse code, was the version that was used to transmit the first telegraph message.
The code may transmitted as an audio tone, a steady radio signal switched on and off (known as continuous wave, or CW), an electrical pulse down a telegraph wire, or as a mechanical or visual signal (e.g. a flashing light).
In general, any code representing written symbols as variable length signals can be called a Morse code, but the term is used specifically for the two kinds of Morse code used for the English alphabet and associated symbols. American Morse Code was used in the wired telegraph systems that made up the first long-distance electronic communication system. International Morse Code, which uses only dots and dashes (eliminating the pause), is used today.
Telegraph companies charged based on the length of the message sent. Elaborate commercial codes were developed that encoded complete phrases in five-letter groups that were sent as single words. Examples: BYOXO ("Are you trying to crawl out of it?"), LIOUY ("Why do you not answer my question?"), and AYYLU ("Not clearly coded, repeat more clearly."). The letters of these five-letter code words were sent individually using Morse code. In networking terminology we would say the commercial code is layered on top of Morse code. Still in use in Amateur Radio are the Q code and Z code; they were and are used by the operators themselves for service information like link quality, frequency changes, and telegram numbering.
On January 8, 1838 Alfred Vail demonstrated a telegraph code using dots and dashes which was the forerunner of Morse code.
When considered as a standard for information encoding, Morse code had a successful lifespan that has not yet been surpassed by any other encoding scheme. Morse code was used as an international standard for maritime communication until 1999. When the French navy ceased using Morse code in 1997, the final message transmitted was "Calling all. This is our last cry before our eternal silence."
Virtually extinct, American Morse Code uses a slightly different structure of dots and dashes and uniquely spaces also to represent numbers, letters, and special characters. This style of morse code was developed for land operators working over telegraph wire rather than via radio signals.
This older, alternate style of code was developed to accommodate the way in which operators listened to morse code sent to them. Rather than hearing tones from a speaker or headphones as we do now using International Morse Code, in these earliest days of telegraphy one would hear clicks from a mechanical sounding device, or often from the sending key which was switched to receive in slave mode when not transmitting.
Most often these operators worked for the railroad or later for Western Union and the like. Thomas Alva Edison was such an operator in his teenage years, as were countless youths of his time.
International Morse code is still in use today, although it has become almost exclusively the province of amateur radio operators.
Until 2003 the International Telecommunications Union (ITU) mandated Morse code proficiency as part of the amateur radio licensing procedure throughout the world. In some countries, certain parts of the amateur radio bands are still reserved for transmission of Morse code signals only.
Since Morse relies on only a steady (unmodulated) radio signal, it requires less complex equipment than other forms of radio communication, and it can be used in very high noise / low signal environments. It also requires very little bandwidth and facilitates communication between amateur radio operators who do not share a common mother tongue and would have great difficulty in communicating using voice modes. It is also very popular among QRP operators.
In the United States until 1991, a demonstration of the ability to send and receive Morse code at 5 words per minute (WPM) was required to receive an FCC amateur radio license permitting use of the HF bands. Until 1999 proficiency at the 20 WPM level was required to receive the highest level of amateur license (Extra Class); on December 13, 1999, the FCC reduced the Extra Class requirement 13 WPM.
The World Radiocommunication Conference of 2003 (WRC-03) made optional the international Morse code requirement for amateur radio licensing. Although the requirement remains on the books in the US, Canada, and elsewhere, some countries are working to eliminate the requirement entirely.
Amateur and military radio operators skilled in Morse code can often understand ("copy") code in their heads at rates in excess of 40 WPM. Although the traditional telegraph key is still used by many amateurs, the use of semi- and fully-automatic electronic keyers is prevalent today. Computer software is also frequently employed to produce and decode Morse code RF signals.
There are two "symbols" used to represent letters, called dots and dashes or dits and dahs. The length of the dit determines the speed at which the message is sent, and is used as the timing reference. Here is an illustration of the timing conventions. Its intent is to show exact timing - it would normally be written something like this:
(Beginners are taught to send short fast letters with small spaces between the dots and dashes in a symbol and exaggerated spaces between symbols and words. This makes it easier to learn.)
People familiar with Morse Code often speak or write it like this. ("Dah" is pronounced with an "awe" vowel sound).
{| border=1 cellspacing=0 cellpadding=2
! Letter
! Code
! Letter
! Code
|-
| A
| *-
| N
| -*
|-
| B
| -***
| O
| ---
|-
| C
| -*-*
| P
| *--*
|-
| D
| -**
| Q
| --*-
|-
| E
| *
| R
| *-*
|-
| F
| **-*
| S
| ***
|-
| G
| --*
| T
| -
|-
| H
| ****
| U
| **-
|-
| I
| **
| V
| ***-
|-
| J
| *---
| W
| *--
|-
| K
| -*-
| X
| -**-
|-
| L
| *-**
| Y
| -*--
|-
| M
| --
| Z
| --**
|}
Numbers
Prosigns are dot/dash sequences that have a special meaning. They are composed of two Morse code alphabetic characters "run together"; that is, that omit the normal pause that would occur if they were being sent as two letters of text. They are normally represented in print by the two letters, often with a ligating bar above them.
Abbreviations differ from prosigns in that they observe normal interletter spacing; that is, they are not "run together" the way prosigns are.
CW Continuous wave
CX Conditions
DE From
DX Distance (sometimes refers to long distance contact)
ES And
FB Fine business (Analogous to "OK")
FCC Federal Communications Commission
FER For
FREQ Frequency
GA Good afternoon or Go ahead (depending on context)
GE Good evening
GM Good morning
GND Ground (ground potential)
GUD Good
HI Laughter
HR Here
HV Have
LID Poor operator
MILS Milliamperes
NIL Nothing
NR Number
OB Old boy
OC Old chap
OM Old man (any male amateur radio operator is an OM)
OO Official Observer
OP Operator
OT Old timer
OTC Old timers club
OOTC Old old timers club
PSE Please
PWR Power
QCWA Quarter Century Wireless Association
R I acknowledge or decimal point (depending on context)
RCVR Receiver
RPT Repeat or report (depending on context)
RST Signal report format (Readability-Signal Strength-Tone)
RTTY Radioteletype
RX Receive
SAE Self addressed envelope
SASE Self addressed, stamped envelope
SED Said
SEZ Says
SIG Signal
SIGS Signals
SKED Schedule
SN Soon
SOS international distress call
SRI Sorry
STN Station
TEMP Temperature
TMW Tomorrow
TNX Thanks
TU Thank you
TX Transmit
U You
UR Your or you're (depending on context)
URS Yours
VY Very
WDS Words
WKD Worked
WL Will
WUD Would
WX Weather
XMTR Transmitter
XYL Wife
YL Young lady (used of any female)
73 Best regards
88 Love and kisses
See also: Q code
The skill to have sensible conversations with Morse is more than knowing just the alphabet. To make communication efficient, there are many internationally agreed patterns of communication.
A sample cw conversation between station 1 (s1) and station 2 (s2)
s1:
History of Morse
American Morse Code
Modern International Morse Code
Timing and representation
-- --- *-* *** * / -*-* --- -** *
M O R S E (space) C O D E
where - represents dah and * represents dit. Here's the exact conventional timing for the same message (= represents signal on, . represents signal off, each for the length of a dit):
A dah is conventionally 3 times as long as a dit. Spacing between dits and dahs in a character is the length of one dit. Spacing between letters in a word is the length of a dah (3 dits). Spacing between words is 7 dits. .
....
....=.
.=...=.=.=...=........=.
.=....
.===
^ ^ ^ ^ ^
| dah dit | word space
symbol space letter space-- --- *-* *** * / -*-* --- -** *
DahDah DahDahDah DiDahDit DiDiDit Dit, DahDiDahDit DahDahDah DahDiDit Dit.Letters, numbers, punctuation, prosigns
0 -----
1 *----
2 **---
3 ***--
4 ****-
5 *****
6 -****
7 --***
8 ---**
9 ----*
Common punctuationPeriod *-*-*-
Comma --**--
Question Mark **--**
Double Dash -***-
Hyphen -****-
Fraction Bar -**-*
Special Symbols (Prosigns)AR *-*-* Stop (end of message), often written +
AS *-*** Wait (for 30 s - 60 s), respond with C (yes)
K -*- Invitation to transmit
(normally follows AR to indicate 'back-to-you')
SK ***-*- End (end of contact), sometimes written VA
BT -***- Separator, sometimes written =Not really prosigns, an error may be indicated by any of:VE ***-* I will send the last word again
** ** (same)
******** ErrorNon-English extensions to the Morse codeå *--*-
ä *-*-
à *--*-
é **-**
ch ----
ö ---*
ü **--
" *-**-*
! **--*
Commonly used Morse code abbreviations
AA All after (used after question mark to request a repetition)
AB All before (similarly)
ARRL American Radio Relay League
ABT About
ADS Address
AGN Again
ANT Antenna
BN All between
BUG Semiautomatic key
C Yes
CBA Callbook address
CFM Confirm
CLG Calling
CQ Calling any station
CUL See you later
CUZ Because
Conversation with Morse code
CQ CQ CQ de s1 K
Calling anyone (CQ), this is (de) s1, listening (K)
s2:
s1 de s2 K
Calling s1, this is s2, listening
(Now we have a connection)
s1:
VA
Bye.
s2:
VA
Bye.
Stations weren't chatting a lot above, just testing a connection. VA, meaning bye or end, is sent as one letter "..._._" and can thus be marked either SK or VA. Morse Code translators
There are a number of translators on the Web that will convert text to morse code, and play it via a PC: