Procedural signs or prosigns are shorthand signals used in Morse code telegraphy, for the purpose of simplifying and standardizing procedural protocols for landline and radio communication. The procedural signs are distinct from conventional Morse code abbreviations, which consist mainly of brevity codes that convey messages to other parties with greater speed and accuracy. However, some codes are used both as prosigns and as single letters or punctuation marks, and for those, the distinction between a prosign and abbreviation is ambiguous, even in context.
In the broader sense prosigns are just standardised parts of short form radio protocol, and can include any abbreviation. Examples would be K for "okay, heard you, continue" or R for "message, received". [1] [2] In a more restricted sense, "prosign" refers to something analogous to the nonprinting control characters in teleprinter and computer character sets, such as Baudot and ASCII. Different from abbreviations, those are universally recognizable across language barriers as distinct and well-defined symbols.
At the coding level, prosigns admit any form the Morse code can take, unlike abbreviations which have to be sent as a sequence of individual letters, like ordinary text. On the other hand, most prosigns codes are much longer than typical codes for letters and numbers. They are individual and indivisible code points within the broader Morse code, fully at par with basic letters and numbers.
The development of prosigns began in the 1860s for wired telegraphy. Since telegraphy preceded voice communications by several decades, many of the much older Morse prosigns have acquired precisely equivalent prowords for use in more recent voice protocols.
Not all prosigns used by telegraphers are standard: There are regional and community-specific variations of the coding convention used in certain radio networks to manage transmission and formatting of messages, and many unofficial prosign conventions exist; some of which might be redundant or ambiguous. One typical example of something which is not an officially recognized prosign, but is yet fairly often used in Europe, is one or two freely timed dits at the end of a message, I I or ▄ ▄ ▄ ▄ ; it is equivalent to the proword OUT, meaning "I'm done; go ahead". However the official prosign with the same meaning is AR, or ▄ ▄▄▄ ▄ ▄▄▄ ▄ , which takes a little longer to send. [3] [2]
Even though represented as strings of letters, prosigns are rendered without the intercharacter commas or pauses that would occur between the letters shown, if the representation were (mistakenly) sent as a sequence of letters: In printed material describing their meaning and use, prosigns are shown either as a sequence of dots and dashes for the sound of a telegraph, or by an overlined sequence of letters from the International Morse Code, which when sent without the usual spacing, sounds like the prosign symbol.
The best-known example of the convention is the standard distress call preamble: SOS. As a prosign it is not really composed of the three separate letters S, O, and S, (in International Morse: ▄ ▄ ▄ ▄▄▄ ▄▄▄ ▄▄▄ ▄ ▄ ▄ ) but is run together as a single symbol ▄ ▄ ▄ ▄▄▄ ▄▄▄ ▄▄▄ ▄ ▄ ▄ , which is a sign in its own right.
In the early decades of telegraphy, many efficiency improvements were incorporated into operations. Each of the early versions of Morse code was an example of that: With only one glaring exception (Intl. Morse O), they all encoded more common characters into shorter keying sequences, and the rare ones into longer, thus effecting online data compression. The introduction of Morse symbols called procedural signs or prosigns was then just a logical progression. They were not defined by the developers of Morse code, but were gradually introduced by telegraph operators to improve the speed and accuracy of high-volume message handling, especially those sent over that era's problematic long distance communication channels, such as transoceanic cables and later longwave wireless telegraphy.
Among other prosign uses, improvement in the legibility of written messages sent by telegraph (telegrams) using white space formatting was supported by the procedural symbols. To become an efficient telegraph operator it was important to master the Morse code prosigns, as well as the many standard abbreviations used to facilitate checking and re-sending sections of text.
There are at least three methods used to represent Morse prosign symbols:
Although some of the prosigns as-written appear to be simply two adjacent letters, most prosigns are transmitted as digraphs that have no pauses between the patterns that represent the "combined" letters, and are most commonly written with a single bar over the merged letters (if more than one single character) to indicate this. [4] The only difference between what is transmitted for the Morse code prosign vs. the separate letter signs is the presence or absence of an inter-letter space between the two "dit" / "dah" sequences. Although the difference in the transmission is subtle, the difference in meaning is gross:
Because no letter boundaries are transmitted with the codes counted as prosigns, their representation by two letters is usually arbitrary, and may be done in multiple equivalent ways. Normally, one particular form is used by convention, but some prosigns have multiple forms in common use:
Many Morse code prosigns do not have written or printed textual character representations in the original source information, even if they do represent characters in other contexts. For example, when embedded in text the Morse code sequence ▄▄▄ ▄ ▄ ▄ ▄▄▄ represents the "double hyphen" character (normally "=", but also "– –"). [1] When the same code appears alone it indicates the action of spacing down two lines on a page in order to create the white space indicating the start of a new paragraph [2] or new section in a message heading. [1] When used as a prosign, there is no actual written or printed character representation or symbol for a new paragraph (i.e. no symbol corresponding to " ¶ "), other than the two-line white space itself.
Some prosigns are in unofficial use for special characters in languages other than English, for example AA is used unofficially for both the "next line" prosign [b] and for "Ä", [6] [7] neither of which is in the international standard. [1] Other prosigns are officially designated for both characters and prosigns, such as AR equiv. "+", which marks the end of a message. [d] [1] Some genuinely have only one use, such as CT or the equivalent KA ( ▄▄▄ ▄ ▄▄▄ ▄ ▄▄▄ ), the International Morse prosign that marks the start of a new transmission [1] or new message. [2]
The procedure signs below are compiled from the official specification for Morse Code, ITU-R M.1677, International Morse Code, [1] while others are defined the International Radio Regulations for Mobile Maritime Service, including ITU-R M.1170, [8] ITU-R M.1172, [4] and the Maritime International Code of Signals, [5] with a few details of their use appearing in ACP 131, [9] which otherwise defines operating signals, not procedure signals.
The following table of prosigns includes K and R, which could be considered either abbreviations (for "okay, go ahead", and for "received") or prosigns that are also letters. All of the rest of the symbols are not letters, but in some cases are also used as punctuation.
Prosign | Matching voice procedure word | Code symbol | Reference | Explanation |
---|---|---|---|---|
AA | UNKNOWN STATION | ▄ ▄▄▄ ▄ ▄▄▄ | [5] | This meaning is only used for directional signal lights. [5] It has no official use in radio telegraphy, [1] where it is unofficially used to represent an accented letter Ä or Á, [6] [7] or the prosign for "next line", and then only when it is embedded inside a heading section in amateur traffic. [2] |
R | ROGER | ▄ ▄▄▄ ▄ | [4] [2] | Means the last transmission has been received, but does not necessarily indicate the message was understood or will be complied with. |
K | OVER | ▄▄▄ ▄ ▄▄▄ | [1] [2] | Invitation to transmit after terminating the call signal. (e.g. ▄ ▄▄▄ ▄ ▄▄▄ ▄ ▄▄▄ ▄ ▄▄▄ ). |
AR | OUT | ▄ ▄▄▄ ▄ ▄▄▄ ▄ | [4] [1] [2] | End of transmission / End of message / End of telegram. [d] (Same as EC "end copy", and character +.) [e] |
AS | WAIT | ▄ ▄▄▄ ▄ ▄ ▄ | [8] [4] [1] [2] | "I must pause for a few minutes." [f] Also means "I am engaged in a contact with another station [that you may not hear]; please wait quietly." |
ASAR | WAITOUT | ▄ ▄▄▄ ▄ ▄ ▄ ▄ ▄▄▄ ▄ ▄▄▄ ▄ | [11] | I must pause for more than a few minutes. |
VE | VERIFIED | ▄ ▄ ▄ ▄▄▄ ▄ | [1] [2] | Message is verified. |
? | SAY AGAIN? | ▄ ▄ ▄▄▄ ▄▄▄ ▄ ▄ | [1] [11] | When standing alone, a note of interrogation or request for repetition of the immediate prior transmission that was not understood. When ? is placed after a coded signal, modifies the code to be a question or request. |
INT | INTERROGATIVE | ▄ ▄ ▄▄▄ ▄ ▄▄▄ | [11] [9] [12] | Military replacement for the ? prosign; equivalent to Spanish ¿ punctuation mark. When placed before a signal, modifies the signal to be a question/request. [13] [g] |
HH ... | CORRECTION (kor-rek-shun) | ▄ ▄ ▄ ▄ ▄ ▄ ▄ ▄ | [1] [2] | Preceding text was in error. The following is the corrected text. (Same as IIII or EEEEEEEE.) |
HHAR | DISREGARD THIS TRANSMISSIONOUT | ▄ ▄ ▄ ▄ ▄ ▄ ▄ ▄ ▄ ▄▄▄ ▄ ▄▄▄ ▄ | The entire message just sent is in error, disregard it. (Same as EEEEEEEE AR.) [h] | |
BT | BREAK | ▄▄▄ ▄ ▄ ▄ ▄▄▄ | [4] [1] [2] | Start new section of message. Same as character = or rarely – –. |
KA | ATTENTION | ▄▄▄ ▄ ▄▄▄ ▄ ▄▄▄ | [4] [1] [2] | Message begins / Start of work / New message (Starting signal that precedes every transmission session. Sometimes written as CT.) |
SK | OUT | ▄ ▄ ▄ ▄▄▄ ▄ ▄▄▄ | [4] [1] [2] | End of contact / End of work / Line is now free / Frequency no longer in use (Ending signal that follows every transmission session. Occasionally written VA.) |
The following table lists standard abbreviations used for organizing radiotelegraph traffic, however none of them are actual prosigns, despite their similar purpose. All are strictly used as normal strings of one to several letters, never as digraph symbols, and have standard meanings used for the management of sending and receiving messages. Dots following indicate that in use, the abbreviation is always followed by more information.
Abbrev. | Matching voice procedure word | Code symbol | Reference | Explanation |
---|---|---|---|---|
DE ... | [THIS IS] FROM | ▄▄▄ ▄ ▄ ▄ | [4] [1] [2] | Used to precede the name or other identification of the station sending the transmission (Morse abbreviation). |
NIL | NOTHING HEARD | ▄▄▄ ▄ ▄ ▄ ▄ ▄▄▄ ▄ ▄ | General-purpose response to any request or inquiry for which the answer is "nothing" or "none" or "not available" (Morse abbr.). Also means "I have no messages for you." | |
CL | CLOSING | ▄▄▄ ▄ ▄▄▄ ▄ ▄ ▄▄▄ ▄ ▄ | [4] [2] | Announcing station shutdown (Morse abbr.). |
CQ | CALLING | ▄▄▄ ▄ ▄▄▄ ▄ ▄▄▄ ▄▄▄ ▄ ▄▄▄ | [4] [2] | General call to any station (Morse abbr.). |
CP ... ... | CALLING FOR | ▄▄▄ ▄ ▄▄▄ ▄ ▄ ▄▄▄ ▄▄▄ ▄ | [4] | Specific call to two or more named stations (Morse abbr.). |
CS ... | CALLING STATION | ▄▄▄ ▄ ▄▄▄ ▄ ▄ ▄ ▄ | [4] | Specific call to exactly one named station (Morse abbr.). |
CS ? | WHO ? | ▄▄▄ ▄ ▄▄▄ ▄ ▄ ▄ ▄ ▄ ▄ ▄▄▄ ▄▄▄ ▄ ▄ | [4] | What is the name or identity signal of your station? (Morse abbr.) In many contexts, the question mark is optional. |
WA ... | WORD AFTER | ▄ ▄▄▄ ▄▄▄ ▄ ▄▄▄ | [4] [2] | (Morse abbr.) |
WB ... | WORD BEFORE | ▄ ▄▄▄ ▄▄▄ ▄▄▄ ▄ ▄ ▄ | [4] [2] | (Morse abbr.) |
AA ... | ALL AFTER | ▄ ▄▄▄ ▄ ▄▄▄ | [4] [2] | The portion of the message to which I refer is all that follows the text ... (Morse abbr.) |
AB ... | ALL BEFORE | ▄ ▄▄▄ ▄▄▄ ▄ ▄ ▄ | [4] [2] | The portion of the message to which I refer is all that precedes the text ... (Morse abbr.) |
BN ... ... | ALL BETWEEN | ▄▄▄ ▄ ▄ ▄ ▄▄▄ ▄ | [4] [2] | The portion of the message to which I refer is all that falls between ... and ... (Morse abbr.) |
C | CORRECT / YES / AFFIRMATIVE / CONFIRM | ▄▄▄ ▄ ▄▄▄ ▄ | [4] [2] | Answer to prior question is "yes". (Morse abbr.) |
N | NO / NEGATIVE | ▄▄▄ ▄ | [5] [9] | Answer to prior question is "no". (Morse abbr.) [i] |
ZWF ... | WRONG | ▄▄▄ ▄▄▄ ▄ ▄ ▄ ▄▄▄ ▄▄▄ ▄ ▄ ▄▄▄ ▄ | [9] | Your last transmission was wrong. The correct version is ... |
QTR ? | REQUEST TIME CHECK | ▄▄▄ ▄▄▄ ▄ ▄▄▄ ▄▄▄ ▄ ▄▄▄ ▄ ▄ ▄ ▄▄▄ ▄▄▄ ▄ ▄ | [9] | Time-check request. / What is the correct time? (Time is always UTC, unless explicitly requested otherwise, e.g. QTR HST ?) |
QTR ... | TIME IS | ▄▄▄ ▄▄▄ ▄ ▄▄▄ ▄▄▄ ▄ ▄▄▄ ▄ | [9] | The following is the correct UTC in HHMM 24 hour format |
BK | BREAK-IN | ▄▄▄ ▄ ▄ ▄ ▄▄▄ ▄ ▄▄▄ | [4] [2] | Signal used to interrupt a transmission already in progress (Morse abbr.). NATO nets use AX. [9] Some military networks use ▄▄▄▄▄▄▄▄▄▄▄ ≈TTTT instead. |
CFM | CONFIRM / I ACKNOWLEDGE | ▄▄▄ ▄ ▄▄▄ ▄ ▄ ▄ ▄▄▄ ▄ ▄▄▄ ▄▄▄ | [4] [2] | Message received (Morse abbr.). (Same as R.) |
WX ... | WEATHER IS | ▄ ▄▄▄ ▄▄▄ ▄▄▄ ▄ ▄ ▄▄▄ | [4] [2] | Weather report follows (Morse abbr.). |
INTERCO | INTERCO (in-tur-ko) | ▄ ▄ ▄▄▄ ▄ ▄▄▄ ▄ ▄ ▄▄▄ ▄ ▄▄▄ ▄ ▄▄▄ ▄ ▄▄▄ ▄▄▄ ▄▄▄ | [5] [4] | Groups of abbreviations from the International Code of Signals [5] follow (Morse abbr.). |
For the special purpose of exchanging ARRL Radiograms during National Traffic System nets, the following prosigns and signals can be used, most of which are an exact match with ITU-R and Combined Communications Electronics Board (military) standards; a few have no equivalent in any other definition of Morse code procedure signals or abbreviations.
Prosign | Code symbol | Meaning | Comments | Verbalization | As text | |
---|---|---|---|---|---|---|
AA | ▄ ▄▄▄ ▄ ▄▄▄ | Start new line | Space down one line; typewritten as Carriage Return, Line Feed (CR-LF). Only used instead of BT in ARRL batched messages, where BT would prematurely start a pending next section. [2] Also written RT. | di dah di dah | Ä, Á [j] | |
AR | ▄ ▄▄▄ ▄ ▄▄▄ ▄ | Message separator, start new message / telegram. [1] [3] [2] | New Page, space down several lines. [3] Decoder software may show "+". [1] Alternative for "Break" in conversational Morse. [2] Also written RN. | di dah di dah dit | + [1] | |
AS | ▄ ▄▄▄ ▄ ▄ ▄ | Wait [1] [3] | Respond with: SN, or characters "R" (Received) or "C" (Confirmed). [3] [1] | di dah di di dit | & [k] | |
BT | ▄▄▄ ▄ ▄ ▄ ▄▄▄ | Start new section [1] / paragraph [3] [2] | Space down two lines; typewritten CR-LF-LF. Decoder software may show "=". [1] | dah di di di dah | =, – – [1] | |
CT | ▄▄▄ ▄ ▄▄▄ ▄ ▄▄▄ | Start of transmission [1] Start of new message [3] [2] | Attention [3] [2] commencing transmission. Also written KA. | dah di dah di dah | ||
HH ... | ▄ ▄ ▄ ▄ ▄ ▄ ▄ ▄ | Error / correction [1] [3] | Always followed by correct text. [3] Equivalent to both IIII and EEEEEEEE . Sometimes transcribed as "???". | di di di di di di di dit | Ă, Ē, Ě, Ģ, Í, Ī, Ļ, Ľ, Ơ, Ț, Ư | |
K | ▄▄▄ ▄ ▄▄▄ | Invitation for any station to transmit [1] [3] [2] | Lone alphabetic character "K" at the end of a transmission. [3] | dah di dah | K [1] | |
X | ▄▄▄ ▄ ▄ ▄▄▄ | Full stop [3] | Lone alphabetic character "X" surrounded by word spaces. [3] [2] Substitute for period AAA in ARRL batched messages. | dah di di dah | X [1] | |
? | ▄ ▄ ▄▄▄ ▄▄▄ ▄ ▄ | Please say again [1] [3] [2] | Lone question mark "?" from the receiving station in response to a transmission; possibly followed by AA ... or AB ... . [3] | di di dah dah di dit | ? [1] [3] | |
KN | ▄▄▄ ▄ ▄▄▄ ▄▄▄ ▄ | Invitation for named station to transmit [3] | Go ahead, specific named station. [3] Decoder software may show equivalent character "(". [1] | dah di dah dah dit | ( [1] | |
NJ | ▄▄▄ ▄ ▄ ▄▄▄ ▄▄▄ ▄▄▄ | Shift to Wabun code | Shift from Morse code to Wabun code Kana characters. Also written XM. | dah di di dah dah dah | ||
SK | ▄ ▄ ▄ ▄▄▄ ▄ ▄▄▄ | End of work [1] / End of contact [3] [2] / Frequency no longer in use | Also written VA. | di di di dah di dah | ||
SN | ▄ ▄ ▄ ▄▄▄ ▄ | Understood [3] / verify / verified [1] | Message received and checks okay. Alternatively shift from Wabun to Morse code. "SN?" verification requested. Also written VE. | di di di dah dit | Š, Ś [j] | |
SOS | ▄ ▄ ▄ ▄▄▄ ▄▄▄ ▄▄▄ ▄ ▄ ▄ | Start of a distress signal [1] [3] | Only used by the original distressed station, and only for imminent danger to life or property. [1] (ⓘ ) | di di di dah dah dah di di dit | ||
DDD | ▄▄▄ ▄ ▄ ▄▄▄ ▄ ▄ ▄▄▄ ▄ ▄ | Start of a distress signal relayed from another station | Used to forward a copy of a received " SOS ". | dah di di dah di di dah di dit | ||
BK | ▄▄▄ ▄ ▄ ▄ ▄▄▄ ▄ ▄▄▄ | Break in conversation [3] | Morse abbreviation for "back-to you" (Morse abbr.). [3] In conversational Morse some use any of AR, BT, KN, or "K" instead. | dah di di dit da di dah | BK | |
CL | ▄▄▄ ▄ ▄▄▄ ▄ ▄ ▄▄▄ ▄ ▄ | Closing down [3] [2] | Abbreviation for "closing station" (Morse abbr.). | dah di dah dit di dah di dit | CL |
Prosign | Matching voice procedure word | Former code symbol | Explanation | Reference |
---|---|---|---|---|
CQD | Distress call | ▄▄▄ ▄ ▄▄▄ ▄ ▄▄▄ ▄▄▄ ▄ ▄▄▄ ▄▄▄ ▄ ▄ | Obsolete code used to call all stations during distress (see CQ). Replaced by SOS in 1906 (see above). | |
VE | General call | ▄ ▄ ▄ ▄▄▄ ▄ | Code re-used for "Message verified" or "Message understood" (see SN above). [1] Replaced by CQ (see above). [1] | 1937 Royal Navy Signal Card [14] [15] |
NNNNN | Answering sign | ▄▄▄ ▄ ▄▄▄ ▄ ▄▄▄ ▄ ▄▄▄ ▄ ▄▄▄ ▄ | Dropped. | |
i i | Separative sign break | ▄ ▄ ▄ ▄ | Generally replaced by BT, although it is still used in MARS CW operations, [12] and other military standards. [11] Later re-used for both a "ditto" mark and to represent the warning "I repeat" before a duplicated transmission. | |
EEEEE | Error | ▄ ▄ ▄ ▄ ▄ | Exactly five dits (code for digit 5 [1] ). Replaced by HH [1] (exactly eight dits, EEEEEEEE [1] ). | |
RRRRR | Receipt sign | ▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄ | Replaced by R. [1] | |
É (printed as e) | Further message sign | ▄ ▄ ▄▄▄ ▄ ▄ | Re-purposed original ITU symbol for É [1] not used in English. |
Morse code is a telecommunications method which encodes text characters as standardized sequences of two different signal durations, called dots and dashes, or dits and dahs. Morse code is named after Samuel Morse, one of the early developers of the system adopted for electrical telegraphy.
Wireless telegraphy or radiotelegraphy is the transmission of text messages by radio waves, analogous to electrical telegraphy using cables. Before about 1910, the term wireless telegraphy was also used for other experimental technologies for transmitting telegraph signals without wires. In radiotelegraphy, information is transmitted by pulses of radio waves of two different lengths called "dots" and "dashes", which spell out text messages, usually in Morse code. In a manual system, the sending operator taps on a switch called a telegraph key which turns the transmitter on and off, producing the pulses of radio waves. At the receiver the pulses are audible in the receiver's speaker as beeps, which are translated back to text by an operator who knows Morse code.
The International Radiotelephony Spelling Alphabet or simply the Radiotelephony Spelling Alphabet, commonly known as the NATO phonetic alphabet, is the most widely used set of clear-code words for communicating the letters of the Roman alphabet. Technically a radiotelephonic spelling alphabet, it goes by various names, including NATO spelling alphabet, ICAO phonetic alphabet, and ICAO spelling alphabet. The ITU phonetic alphabet and figure code is a rarely used variant that differs in the code words for digits.
The Q-code is a standardised collection of three-letter codes that each start with the letter "Q". It is an operating signal initially developed for commercial radiotelegraph communication and later adopted by other radio services, especially amateur radio. To distinguish the use of a Q-code transmitted as a question from the same Q-code transmitted as a statement, operators either prefixed it with the military network question marker "INT" or suffixed it with the standard Morse question mark UD.
SOS is a Morse code distress signal, used internationally, originally established for maritime use. In formal notation SOS is written with an overscore line, to indicate that the Morse code equivalents for the individual letters of "SOS" are transmitted as an unbroken sequence of three dots / three dashes / three dots, with no spaces between the letters. In International Morse Code three dots form the letter "S" and three dashes make the letter "O", so "S O S" became a common way to remember the order of the dots and dashes. IWB, VZE, 3B, and V7 form equivalent sequences, but traditionally SOS is the easiest to remember.
CQD is one of the first distress signals adopted for radio use. On 7 January 1904 the Marconi International Marine Communication Company issued "Circular 57", which specified that, for the company's installations, beginning 1 February 1904 "the call to be given by ships in distress or in any way requiring assistance shall be 'C Q D' ".
The R-S-T system is used by amateur radio operators, shortwave listeners, and other radio hobbyists to exchange information about the quality of a radio signal being received. The code is a three digit number, with one digit each for conveying an assessment of the signal's readability, strength, and tone. The code was developed in 1934 by Amateur radio operator Arthur W. Braaten, W2BSR, and was similar to that codified in the ITU Radio Regulations, Cairo, 1938.
Ten-codes, officially known as ten signals, are brevity codes used to represent common phrases in voice communication, particularly by US public safety officials and in citizens band (CB) radio transmissions. The police version of ten-codes is officially known as the APCO Project 14 Aural Brevity Code.
A signal strength and readability report is a standardized format for reporting the strength of the radio signal and the readability (quality) of the radiotelephone (voice) or radiotelegraph signal transmitted by another station as received at the reporting station's location and by their radio station equipment. These report formats are usually designed for only one communications mode or the other, although a few are used for both telegraph and voice communications. All but one of these signal report formats involve the transmission of numbers.
Radiotelephony procedure includes various techniques used to clarify, simplify and standardize spoken communications over two-way radios, in use by the armed forces, in civil aviation, police and fire dispatching systems, citizens' band radio (CB), and amateur radio.
CQ is a station code used by wireless operators derived from long established telegraphic practice on undersea cables and landlines, particularly used by those communicating in Morse code,, but also by voice operators, to make a general call. Transmitting the letters CQ on a particular radio frequency means that the transmission is a broadcast or "General Call" to anyone listening, and when the operator sends "K" or says "Go Ahead" it is an invitation for any licensed radio station listening on that frequency to respond. Its use on radio matched the existing use on Morse landline telegraphy and dates from the earliest wireless stations. It was widely used in point-to-point diplomatic and press services, maritime, aviation, and police services until those services eliminated Morse radiotelegraphy. It is still widely used in amateur radio which still has active use of Morse radiotelegraphy.
Modulated continuous wave (MCW) is Morse code telegraphy transmitted using an audio tone to modulate a carrier wave.
American Morse Code — also known as Railroad Morse—is the latter-day name for the original version of the Morse Code developed in the mid-1840s, by Samuel Morse and Alfred Vail for their electric telegraph. The "American" qualifier was added because, after most of the rest of the world adopted "International Morse Code," the companies that continued to use the original Morse Code were mainly located in the United States. American Morse is now nearly extinct—it is most frequently seen in American railroad museums and American Civil War reenactments—and "Morse Code" today virtually always means the International Morse which supplanted American Morse.
A Radio code is any code that is commonly used over a telecommunication system such as Morse code, brevity codes and procedure words.
Morse code abbreviations are used to speed up Morse communications by foreshortening textual words and phrases. Morse abbreviations are short forms, representing normal textual words and phrases formed from some (fewer) characters taken from the word or phrase being abbreviated. Many are typical English abbreviations, or short acronyms for often-used phrases.
A spelling alphabet is a set of words used to represent the letters of an alphabet in oral communication, especially over a two-way radio or telephone. The words chosen to represent the letters sound sufficiently different from each other to clearly differentiate them. This avoids any confusion that could easily otherwise result from the names of letters that sound similar, except for some small difference easily missed or easily degraded by the imperfect sound quality of the apparatus. For example, in the Latin alphabet, the letters B, P, and D sound similar and could easily be confused, but the words "bravo", "papa" and "delta" sound completely different, making confusion unlikely.
A radiogram is a formal written message transmitted by radio. Also known as a radio telegram or radio telegraphic message, radiograms use a standardized message format, form and radiotelephone and/or radiotelegraph transmission procedures. These procedures typically provide a means of transmitting the content of the messages without including the names of the various headers and message sections, so as to minimize the time needed to transmit messages over limited and/or congested radio channels. Various formats have been used historically by maritime radio services, military organizations, and Amateur Radio organizations.
In amateur radio, high-speed telegraphy (HST) is a form of radiosport that challenges amateur radio operators to accurately receive and copy, and in some competitions to send, Morse code transmissions sent at very high speeds. This event is most popular in Eastern Europe. The International Amateur Radio Union (IARU) sponsors most of the international competitions.
In CW Morse code operations, QSK or full break-in operation describes an operating mode in which the transmitting station can detect signals from other stations between the elements or letters of the Morse transmission. This allows other stations to interrupt the transmitting station between individual coding elements, and such allows for a conversational style of communication.
The QSA code and QRK code are interrelated and complementary signal reporting codes for use in wireless telegraphy. An enhanced format, SINPO code, was published in the ITU Radio Regulations, Geneva, 1959, but is longer and unwieldy for use in the fast pace of Morse code communications.
The Deutsch-Österreichischer Telegraphenverein officially adopted Gerke's redaction / revision of Morse code in 1851.[ full citation needed ]
{{cite conference}}
: CS1 maint: multiple names: authors list (link) CS1 maint: numeric names: authors list (link)