Morse code

Pre-Morse telegraphs and codes Early in the nineteenth century, European experimenters made progress with electrical signaling systems, using a variety of techniques including static electricity and electricity from Voltaic piles producing electrochemical and electromagnetic changes. These experimental designs were precursors to practical telegraphic applications. Morse's original telegraph receiver used a mechanical clockwork to move a paper tape. When an electrical current was received, an electromagnet engaged an armature that pushed a stylus onto the moving paper tape, making an indentation on the tape. When the current was interrupted, a spring retracted the stylus and that portion of the moving tape remained unmarked. In his earliest design for a code, Morse had planned to transmit only numerals, and to use a codebook to look up each word according to the number which had been sent. However, the code was soon expanded by Alfred Vail in 1840 to include letters and special characters, so it could be used more generally. Vail estimated the English language letter frequency by counting the movable type he found in the type cases of a local newspaper in Morristown, New Jersey. In the Royal Australian Navy, Morse was still regarded as crucial, for example during very close quarters replenishment at sea, when it is preferable not to use radio transmitters while fuel is being transferred between ships. The United States Coast Guard has ceased all use of Morse code on the radio, and no longer monitors any radio frequencies for Morse code transmissions, including the international medium frequency (MF) distress frequency of However, the Federal Communications Commission still grants commercial radiotelegraph operator licenses to applicants who pass its code and written tests. Meanwhile, licensees have reactivated the old California coastal Morse station KPH and regularly transmit from the site under either that call sign or as KSM. Similarly, a few U.S. museum ship stations are operated by Morse enthusiasts. Internationally, The CW Operators' Club (CWops), has been established for amateur radio operators who use Morse code. At the end of 2025, the club's ambassador for Oceania estimated that the 12,000 amateur radio users in Australia included 700 practitioners of Morse, with 300 of them being regular users of the code. He said that a user committed to regular practice could become reasonably competent in Morse within about three to four months. == Operator proficiency ==

used in conjunction with an electronic keyer to generate high-speed Morse code, the timing of which is controlled by the keyer. Morse code speed is measured in words per minute (WPM) or characters per minute (CPM). Characters have differing lengths because they contain differing numbers of dits and dahs. Consequently, words also have different lengths in terms of dot duration, even when they contain the same number of characters. For this reason, some standard word is adopted for measuring operators' transmission speeds: Two such standard words in common use are and . Operators skilled in Morse code can often understand ("copy") code in their heads at rates in excess of 40 WPM. In addition to knowing, understanding, and being able to copy the standard written alpha-numeric and punctuation characters or symbols at high speeds, skilled high-speed operators must also be fully knowledgeable of all of the special unwritten Morse code symbols for the standard Prosigns for Morse code and the meanings of these special procedural signals in standard Morse code communications protocol. International contests in code copying are still occasionally held. In July 1939 at a contest in Asheville, North Carolina in the United States, Theodore Roosevelt McElroy () set a still-standing record for Morse copying, 75.2 WPM. Pierpont (2004) also notes that some operators may have passed 100 WPM. By this time, they are "hearing" phrases and sentences rather than words. The fastest speed ever sent by a straight key was achieved in 1942 by Harry Turner (call sign|) (d. 1992) who reached 35 WPM in a demonstration at a U.S. Army base. To accurately compare code copying speed records of different eras it is useful to keep in mind that different standard words (50 dit durations versus 60 dit durations) and different interword gaps (5 dit durations versus 7 dit durations) may have been used when determining such speed records. For example, speeds run with the standard word and the standard may differ by up to 20%. Today among amateur operators there are several organizations that recognize high-speed code ability, one group consisting of those who can copy Morse at 60 WPM. Also, Certificates of Code Proficiency are issued by several amateur radio societies, including the American Radio Relay League. Their basic award starts at 10 WPM with endorsements as high as 40 WPM, and are available to anyone who can copy the transmitted text. Members of the Boy Scouts of America may put a Morse interpreter's strip on their uniforms if they meet the standards for translating code at 5 WPM. Through May 2013, the First, Second, and Third Class (commercial) Radiotelegraph Licenses using code tests based upon the standard word were still being issued in the United States by the Federal Communications Commission. The First Class license required 20 WPM code group and 25 WPM text code proficiency, the others 16 WPM code group test (five letter blocks sent as simulation of receiving encrypted text) and 20 WPM code text (plain language) test. It was also necessary to pass written tests on operating practice and electronics theory. A unique additional demand for the First Class was a requirement of a year of experience for operators of shipboard and coast stations using Morse. This allowed the holder to be chief operator on board a passenger ship. However, since 1999 the use of satellite and very high-frequency maritime communications systems (GMDSS) has made them obsolete. (By that point meeting experience requirement for the First was very difficult.) Currently, only one class of license, the Radiotelegraph Operator License, is issued. This is granted either when the tests are passed or as the Second and First are renewed and become this lifetime license. For new applicants, it requires passing a written examination on electronic theory and radiotelegraphy practices, as well as 16 WPM code-group and 20 WPM text tests. However, the code exams are currently waived for holders of Amateur Extra Class licenses who obtained their operating privileges under the old 20 WPM test requirement. == International Morse code ==

Morse codes of one version or another have been in use for more than 160 years — longer than any other electrical message encoding system. What is today called "Morse code" is different from what was originally actually developed by Vail and Morse. The Modern International Morse code, or continental code, was created by Friedrich Clemens Gerke in 1848 and initially used for telegraphy between Hamburg and Cuxhaven in Germany. Gerke changed nearly half of the alphabet and all of the numerals, providing the foundation for the modern form of the code. After some minor changes to the letters and a complete revision of the numerals, International Morse Code was standardized by the International Telegraphy Congress in 1865 in Paris, and later became the standard adopted by the International Telecommunication Union (ITU). Morse and Vail's final code specification, however, was only really used for land-line telegraphy in the United States and Canada, with the International code used everywhere else, including all ships at sea and sailing in North American waters. Vail's version became known as American Morse code or railroad code, and is now almost never used, with the possible exception of historical re-enactments. Aviation In aviation, pilots use radio navigation aids. To allow pilots to ensure that the stations they intend to use are serviceable, the stations transmit a set of identification letters (usually a two-to-five-letter version of the station name) in Morse code. Station identification letters are shown on air navigation charts. For example, the VOR-DME based at Vilo Acuña Airport in Cayo Largo del Sur, Cuba is identified by "UCL", and Morse code is repeatedly transmitted on its radio frequency. In some countries, during periods of maintenance, the facility may instead transmit the signal (), or the identification may be removed, which tells pilots and navigators that the station is unreliable. In Canada, the identification is removed entirely to signify the navigation aid is not to be used. For example, the Android operating system versions 5.0 and higher allow users to input text using Morse Code as an alternative to a keypad or handwriting recognition. These devices may to some degree need to be adapted to specific mobility capabilities. {{blockquote|For people with severe disabilities, both one- and two-switch Morse can be difficult because both depend, to some extent, on timing. ... access products can also offer "three-switch Morse". In three-switch Morse code, one switch signals dit, while another signals dah, just like two-switch Morse. But a third switch is used to indicate that the letter is complete. This removes the necessity of timing to send Morse code. Morse can be sent by persons with severe motion disabilities, as long as they have some minimal motor control. An original solution to the problem that caretakers have to learn to decode has been an electronic typewriter with the codes written on the keys. Codes were sung by users; see the voice typewriter employing Morse or votem. Morse code can also be translated by computer and used in a speaking communication aid. In some cases, this means alternately blowing into and sucking on a plastic tube ("sip-and-puff" interface). An important advantage of Morse code over row column scanning is that once learned, it does not require looking at a display. Also, it appears faster than scanning. In one case reported in the radio amateur magazine QST, an old shipboard radio operator who had a stroke and lost the ability to speak or write could communicate with his physician (a radio amateur) by blinking his eyes in Morse. Two examples of communication in intensive care units were also published in QST magazine. Another example occurred in 1966 when prisoner of war Jeremiah Denton, brought on television by his North Vietnamese captors, Morse-blinked the word . In these two cases, interpreters were available to understand those series of eye-blinks. ==Representation, timing, and speeds==

International Morse code is composed of five elements: Morse messages are generally transmitted by a hand-operated device such as a telegraph key, so there are variations introduced by the skill of the sender and receiver — more experienced operators can send and receive at faster speeds. In addition, individual operators differ slightly, for example, using slightly longer or shorter dahs or gaps, perhaps only for particular characters. This is called their "fist", and experienced operators can recognize specific individuals by it alone. A good operator who sends clearly and is easy to copy is said to have a "good fist". A "poor fist" is a characteristic of sloppy or hard to copy Morse code. Digital storage Morse code is transmitted using just two states (on and off). Morse code may be represented as a binary code, and that is what telegraph operators do when transmitting messages. Working from the above ITU definition and further defining a bit as a dot time, a Morse code sequence may be crudely represented a combination of the following five bit-strings: • short mark, dot or dit (): '1'b • longer mark, dash or dah (): '111'b • intra-character gap (between the dits and dahs within a character): 0 • short gap (between letters): '000'b • medium gap (between words): '0000000'b The marks and gaps alternate: Dits and dahs are always separated by one of the gaps, and that the gaps are always separated by a dit or a dah. A more efficient binary encoding uses only two-bits for each dit or dah element, with the 1 dit-length pause that must follow after each automatically included for every 2 bit code. One possible coding is by number value for the length of signal tone sent one could use '01'b for a dit and the automatic single-dit pause after it, and '11'b for a dah and the automatic single-dit following pause, and '00'b for the extra pause between letters (in effect, an end-of-letter mark). That leaves the code '10'b available for some other purpose, such as an escape character, or to more compactly represent the extra space between words (an end-of-word mark) instead of (only 6 dit lengths, since the 7th is automatically inserted as part of the prior dit or dah). Although the dit and inter-letter pauses work out to be the same, for any letter containing a dah, the two-bit encoding uses digital memory more compactly than the direct-conversion bit strings mentioned above. Including the letter-separating spaces, all International Morse letter codes pack into 12 bits or less (5 symbols), and most fit into 10 bits or less (4 symbols); most of the procedural signs fit into 14 bits, with a few only needing 12 bits (5 symbols); and all digits require exactly 12 bits. For example, Morse ( + 2 extra empty dits for "end of letter") would binary-encode as '11'b, '11'b, '01'b, '00'b; when packed it is = 'F4'x, which stores into only one byte (two nibbles) (as does every three-element code). The bit encoding for the longer method mentioned earlier the same letter would encode as '1110'b, '1110'b, '1000'b = = 'EE8'x, or one-and-a-half bytes (three nibbles). The space saving allows small devices, like portable memory keyers, to have more and longer International Morse code sequences in small, conventional device-driver microprocessors' RAM chips. Cable code The very long time constants of 19th and early 20th century submarine communications cables required a different form of Morse signalling. Instead of keying a voltage on and off for varying times, the dits and dahs were represented by two polarities of voltage impressed on the cable, for a uniform time. Timing Below is an illustration of timing conventions. The phrase , in Morse code format, would normally be written something like this, where represents dahs and represents dits: : Next is the exact conventional timing for this phrase, with representing "signal on", and representing "signal off", each for the time length of exactly one dit: : Spoken representation Morse code is often spoken or written with dah for dashes, dit for dots located at the end of a character, and di for dots located at the beginning or internally within the character. Thus, the following Morse code sequence: : is spoken (or sung): : For use on radio, there is little point in learning to read Morse written in dashes and dots, as above; rather, the sounds of all of the letters and symbols need to be learned, for both sending and receiving. Speed in words per minute All Morse code elements depend on the dot / dit length. A dah is the length of 3 dits (with no gaps between), and spacings are specified in number of dit lengths. An unambiguous method of specifying the transmission speed is to specify the dit duration as, for example, . Specifying the dit duration is, however, not the common practice. Morse code transmission rate is typically specified in groups per minute, commonly referred to as words per minute. The time needed to transmit the word is typically the standard "word" for calculating the "word per minute" rate. Standards using other "words" such as are also seen occasionally, so a reported rate may be ambiguous if this is not specified. mimics a word rate that is typical of natural language words and reflects the benefits of Morse code's shorter code durations for common characters such as and . offers a word rate that is typical of 5 letter code groups (sequences of random letters). Using the word as a standard, the number of dit units is 50 and a simple calculation shows that the dit length at 20 words per minute is . Using the word with 60 dit units, the dit length at 20 words per minute is . Because Morse code is usually sent by hand, it is unlikely that an operator could be that precise with the dit length, and the individual characteristics and preferences of the operators usually override the standards. For commercial radiotelegraph licenses in the United States, the Federal Communications Commission specifies tests for Morse code proficiency in words per minute and in code groups per minute. The FCC specifies that a "word" is 5 characters long. The Commission specifies Morse code test elements at 16 code groups per minute, 20 words per minute, 20 code groups per minute, and 25 words per minute. The word per minute rate would be close to the standard, and the code groups per minute would be close to the standard. While the Federal Communications Commission no longer requires Morse code for amateur radio licenses, the old requirements were similar to the requirements for commercial radiotelegraph licenses. A difference between amateur radio licenses and commercial radiotelegraph licenses is that commercial operators must be able to receive code groups of random characters along with plain language text. For each class of license, the code group speed requirement is slower than the plain language text requirement. For example, for the Radiotelegraph Operator License, the examinee must pass a 20 word per minute plain text test and a 16 word per minute code group test. Based upon a 50 dit duration standard word such as , the time for one dit duration or one unit can be computed by the formula: : where:    is the unit time, or dit duration in milliseconds, and    is the speed in WPM. High-speed telegraphy contests are held; according to the Guinness Book of Records in June 2005 at the International Amateur Radio Union's 6th World Championship in High Speed Telegraphy in Primorsko, Bulgaria, Andrei Bindasov of Belarus transmitted 230 Morse code marks of mixed text in one minute. Farnsworth speed Sometimes, especially while teaching Morse code, the timing rules above are changed so two different speeds are used: A character speed and a text speed. The character speed is how fast each individual letter is sent. The text speed is how fast the entire message is sent. For example, individual characters may be sent at a 13 words-per-minute rate, but the intercharacter and interword gaps may be lengthened so the word rate is only 5 words per minute. Using different character and text speeds is, in fact, a common practice, and is used in the Farnsworth method of learning Morse code. Alternative display of common characters in International Morse code Some methods of teaching Morse code use a dichotomic search table. tree: The graph branches left for each dit and right for each dah until the character representation is reached. Official ITU codes are shown as black letters on dark grey, and are complete, including punctuation; a few non-ITU extensions are shown in outline-font on light grey, but many others are left out. ITU prosigns are circled in red with red text and are complete; unofficial prosigns are orange and are mostly complete. == Learning methods ==

People learning Morse code using the Farnsworth method are taught to send and receive letters and other symbols at their full target speed, that is with normal relative timing of the dits, dahs, and spaces within each symbol for that speed. The Farnsworth method is named for Donald R. "Russ" Farnsworth, also known by his call sign, . However, initially exaggerated spaces between symbols and words are used, to give "thinking time" to make the sound "shape" of the letters and symbols easier to learn. The spacing can then be reduced with practice and familiarity. Another popular teaching method is the Koch method, invented in 1935 by the German engineer and former stormtrooper Ludwig Koch, which uses the full target speed from the outset but begins with just two characters. Once strings containing those two characters can be copied with 90% accuracy, an additional character is added, and so on until the full character set is mastered. In North America, many thousands of individuals have increased their code recognition speed (after initial memorization of the characters) by listening to the regularly scheduled code practice transmissions broadcast by , the station at the American Radio Relay League's headquarters or by listening to the archived recordings available at its website. the United States military taught Morse code as an 81 day self-paced course, having phased out more traditional classes. Mnemonics movement founder Baden-Powell's mnemonic chart from 1918 Visual mnemonic charts have been devised over the ages. Baden-Powell included one in the Girl Guides handbook in 1918. In the United Kingdom, many people learned the Morse code by means of a series of words or phrases that have the same rhythm as a Morse character. For instance, in Morse is which can be memorized by the phrase "God Save the Queen", and the Morse for is which can be memorized as "Did she like it?" A well-known Morse code rhythm from the Second World War period derives from Beethoven's Fifth Symphony, the opening phrase of which was regularly played at the beginning of BBC broadcasts. The timing of the notes corresponds to the Morse for , (), promoted by prime minister Churchill as ''"'V' for Victory"''. ==Characters and prosigns==

Nonstandard punctuation, characters with diacritics, and non-Latin letters are not present in either ITU-R M.1172 or ITU-R M.1677-1, except for . Cut numbers Most numbers have an unofficial short-form, given in the table below. They are only used when both the sender and the receiver understand that numbers, and not letters, are intended; for example, one often sees the most common R-S-T signal report rendered as #double_dagger_anchor| instead of . Cut numbers are made by reducing multiple dahs in the standard Morse number codes to only one dah, but keeping all the dits as-is. This leaves the codes for and unchanged. : Prosigns Prosigns for Morse code are special (usually) unwritten procedural signals or symbols that are used to indicate changes in communications protocol status or white space text formatting actions. Almost all prosigns are also used to encode special characters, such as , , or ; the receiving telegrapher must distinguish the character-meaning from the prosign-meaning by context. Symbol representations The symbols , , and are not defined inside the official ITU-R International Morse Code Recommendation, but informal conventions for them exist. (The symbol was formally added in 2004. The and symbols both have recommended multi-character encodings (see below).) ; Exclamation mark : There is no standard representation for the exclamation mark , although the digraph () was proposed in the 1980s by the Heathkit Company. While Morse code translation software prefers the Heathkit version, on-air use is not yet universal, as some amateur radio operators in North America and the Caribbean continue to use the older digraph () copied over from American Morse landline code. or , , which some telegraphers unofficially use for an exclamation mark , is shared with unofficial letters , , and used in some non-Latin alphabets. ; Currency symbols : The ITU has never formally codified any currency symbols into Morse code: The unambiguous ISO 4217 currency codes are preferred for transmission (e.g. CNY, EUR, GBP, JPY, KRW, USD, etc.). The dollar sign($) was represented in the Phillips Code collection of abbreviations as two characters "". Eventually operators dropped the intervening space and merged the two letter code or abbreviation into the single unofficial punctuation encoding (). ; Ampersand ( & ) : The suggested unofficial encoding of the ampersand sign listed above, often shown as , is also the official Morse prosign for wait. In addition, the American Morse encoding for an ampersand () was similar to (), adapted from the code for ampersand in Railroad Morse. hams have nearly universally carried over this use as an abbreviation for "and" (e.g. "the weather here is cold and rainy"). Since is well established and slightly quicker than , there is no motive for replacing it. ; Keyboard "at" sign ( @ ) : On 24 May 2004the 160th anniversary of the first public Morse telegraph transmissionthe Radiocommunication Bureau of the International Telecommunication Union (ITU-R) formally added the ("commercial at" or "commat") character to the official Morse character set, using the sequence denoted by the digraph:  . : This sequence was reported to have been chosen to represent "A[t] C[ommercial]", or a inside a swirl represented by a The new character facilitates sending e‑mail addresses by Morse code, and is notable since it is the first official addition to the Morse set of characters since World War I. ; Percent ( % ) and permille ( ‰ ) signs : Percent and permille signs should be encoded with zeroes separated by a slash, joined to the preceding number by a dash; so e.g. "4%" would be sent as "", and "5‰" as "", and "6.7%" as "". ; Underscore : The underscore code is unofficial. Typically, when a whole word is meant to be underlined, the word begins with an underscore mark, followed by a letter space and the first letter of the word, and ends with the last letter of the word, followed by a letter space and another underscore mark. For example, read __ as "". Telegraphers may improvise other forms of use as needed (for example, for an underscore character embedded in a computer software keyword). Diacritics and non-Latin extensions is the only accented character that is encoded in the ITU-R Morse code standard. The typical tactic for creating Morse codes for other Latin characters with diacritics and non-Latin alphabetic scripts has been to begin by simply re-using the International Morse codes already used for letters whose sound matches the sound of the local alphabet. Gerke code (the predecessor to International Morse) was in official use in central Europe and included four characters not included in the International Morse standard: , , , and . These four have served as a starting point for other languages that use an alphabetic script, but require codes for letters not accommodated by International Morse. The usual method has been to first transliterate the sounds represented by the International code and the four unique Gerke codes into the local alphabet, hence Greek, Hebrew, Russian, and Ukrainian Morse codes. If more codes are needed, one can either invent a new code or convert an otherwise unused code from either code set to the non-Latin letter. For example: • Spanish letter in Spanish Morse is ; it is a unique code specific to the Spanish language (although also used elsewhere for equivalent ), and is not used in either International Morse nor in Gerke Morse. • For the Greek letter , Greek Morse code uses the International Morse code for , , which has no corresponding letter in modern Greek. Except for the code being otherwise unused, the choice is arbitrary: and have no historical, phonetic, or shape relationship. For Russian and Bulgarian, Russian Morse code maps the Cyrillic characters to four-element codes. Many of those characters are encoded the same as their Latin alphabet look-alikes or sound-alikes (, , , , , , , , , etc.). The Bulgarian alphabet contains 30 characters, which exactly matches the number of all possible permutations of 1, 2, 3, and 4 dits and dahs (Russian is used as Bulgarian , Russian is used as Bulgarian ). Russian requires two more codes, for the letters and which are each encoded with 5 elements. Non-alphabetic scripts require more radical adaption. Japanese Morse code (Wabun code) has a separate encoding for kana script; although many of the codes are used for International Morse, the sounds they represent are mostly unrelated. The Japanese / Wabun code includes special prosigns for switching back-and-forth from International Morse: signals a switch from International Morse to Wabun, and to return from Wabun to International Morse. For Chinese, Chinese telegraph code is used to map Chinese characters to four-digit codes and send these digits out using standard Morse code. Korean Morse code uses the SKATS mapping, originally developed to allow Korean to be typed on western typewriters. SKATS maps hangul characters to arbitrary letters of the Latin script and has no relationship to pronunciation in Korean. Unusual variants During early World War I (1914–1916), Germany briefly experimented with 'dotty' and 'dashy' Morse, in essence adding a dot or a dash at the end of each Morse symbol. Each one was quickly broken by Allied SIGINT, and standard Morse was resumed by Spring 1916. Only a small percentage of Western Front (North Atlantic and Mediterranean Sea) traffic was in 'dotty' or 'dashy' Morse during the entire war. In popular culture, this is mostly remembered in the book The Codebreakers by David Kahn and in the national archives of the UK and Australia (whose SIGINT operators copied most of this Morse variant). Kahn's cited sources come from the popular press and wireless magazines of the time. Other variations include forms of "fractional Morse" or "fractionated Morse", which recombine the characters of the Morse codeencoded message and then encrypt them using a cipher in order to disguise the text. ==Decoding software==

Decoding software for Morse code ranges from software-defined wide-band radio receivers, coupled to the Reverse Beacon Network, which decodes signals and detects messages on ham bands, to smartphone applications. ==See also==