Prosigns for Morse code

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Morse code prosigns or procedural signals are special unique dot/dash sequence symbols e.g. (· — · —) that do not represent written or printed alpha-numeric or punctuation text characters.[1] Prosigns are special unique stand alone (normally unwritten) Morse code symbols, that have particular functions, such as: indicating changes of transmission communications protocol status, and indicating (or initiating) textual white space formatting.[2] These special Morse symbols, although preceding modern teleprinter (teletypewriter) and computer character set control characters by many decades, play a role similar to the (normally unprinted) control characters of modern computer and teleprinter character set codes such as the: Baudot, Murray, ITA2, ASCII, Unicode and EBCDIC codes.

Morse code prosign symbols have been used by telegraphers (American English), or telegraphists (British English), for over 140 years, predating modern character set code control characters by many decades. Traditionally Morse code is encoded or sent manually by telegraphers using hand operated telegraph keys and decoded or copied as the Morse signals are received by ear in real time. Morse prosigns mostly constitute unique dot/dash sequence code symbols separate from those of alpha-numeric and punctuation Morse character symbols and have the same status as the normally written symbols. Mastery of prosigns is an important part of becoming a fluent telegrapher/telegraphist.

Prosign symbol representations[edit]

There are at least three ways to represent (normally unwritten) Morse prosigns. Prosigns are defined and uniquely represented by their corresponding dot/dash sequence symbols and their distinctive audible sounds. Alternatively prosigns may be non-uniquely represented in written or printed form by alpha-numeric character groups that are specially delimited to indicate that the delimited characters are intended to be run-together or concatenated. Although included in the transmitted Morse symbol data streams during normal keying operations Morse prosigns are never explicitly represented in written or printed form during normal sending and receiving operations. A couple of different delimiting annotations described in the following paragraph are used to help represent prosigns.

Illustrative written delimitation of the character groups concatenated to create prosign symbols is effected by specially annotating the otherwise normal looking character groups. Common annotations used to delimit character groups that represent prosigns are either an over line extended over the character group (AA) or, a set of angle brackets surrounding the character group (<AA>).[2] Here AA represents the unique dot/dash sequence symbol (· — · —) which can be verbalized as the sound ("didahdidah") and which for telegraphers indicates the initiation of a new line in a text message. For skilled telegraphers it is the unique audible sound that is most representative of Morse code prosigns.

Delimited concatenated character groups representing prosigns are used for illustrative purposes only and have no intrinsic meaning beyond that of memory aid. Normal Morse inter-character spacing is three dot durations (e.g. the duration of a dash). Conversely, when sent run-together, the concatenated Morse characters are separated by only one dot duration thus uniquely creating and representing the corresponding prosign. The unique sound of concatenated character groups used to form the unique prosign symbols is markedly different from the sounds of the individual concatenated characters themselves. Different delimited concatenated character groups might possibly represent or correspond to the unique Morse prosign symbols.

For example, the unique prosign symbol represented by AA could alternatively be written as EK. The grouping AA is the most common way of illustrating the formation of this unique prosign. Another example of a prosign character grouping is BT, that indicates the white space required to begin a new paragraph. This new paragraph prosign is most commonly illustrated by the concatenated characters B and T representing the unique dot/dash sequence (— · · · —) that can only be uniquely verbalized as the sound ("dahdidididah"). Alternatively BT might be illustrated as TV, NU, or DA.

Morse code is an audible language wherein sounds are the most important symbol characteristics. As proficient telegraphers memorize the sounds of alpha-numeric and punctuation Morse characters rather than their dot/dash sequences, telegraphers must also memorize the unique sounds that represent the prosigns, rather than their corresponding dot/dash sequences or their corresponding non-unique concatenated character groups.

Morse prosigns and modern keyboard operations[edit]

Morse code is over a century old. Fluent Morse code telegraphers still enjoy sending Morse code and the traditional Morse prosigns using manually operated mechanical keys or electronic keyers. Although Morse code is no longer used in commercial practices, the use of hand sent Morse code seems to be growing among amateur radio operators even though Morse proficiency is no longer required to obtain an amateur radio license. As intrepid sailboat sailors, in the modern age of the powerboat, yearn for the heel of sailboats in the wind, there are those who send Morse code by hand in the modern age of the Internet. Nevertheless, some will mix modernity with Morse and choose to send Morse with keyboard operated software applications rather than telegraph keys. The following paragraphs address difficulties encountered when mixing modern keyboard operated computers with century old Morse code prosigns.

Modern keyboard operated teleprinter and computer character set codes, such as the Baudot, Murray, ITA2, ASCII, Unicode and EBCDIC codes, use fixed length symbols while Morse code uses bandwidth efficient variable length symbols sent by telegraphers using hand operated mechanical telegraph keys which permits creating (normally unwritten) Morse prosigns by simply concatenating existing (normally written) Morse symbols. This concatenation is achieved by simply pausing for only one dot duration between the concatenated characters instead of the normal three dot duration pause between non-concatenated characters. Modern fixed length keyboard generated symbols do not allow such concatenation, instead often requiring simultaneous multi-key actions to generate control characters. Although created by Samuel Morse and Alfred Vail in the 1840s, without benefit of the modern 1940's era information theory concepts of Claude Shannon, the bandwidth efficiency of variable length symbol Morse code design, wherein Alfred Vail assigned shorter Morse code symbols to more often used source symbols, is today readily understood in terms of Claude Shannon's modern era source coding (or data compression) techniques, e.g. Huffman codes, arithmetic codes, Lempel-Ziv codes, etc.

Modern teleprinter and computer keyboards contain so-called function keys that generate the corresponding fixed length alpha-numeric, punctuation and control characters symbols dictated by the given character set code. Function keys generally represent non-written code symbols (control characters) and include keys labeled as: Alt, Ctrl, Enter, Shift, Tab, F1, F2, F3, etc. or simply left unlabeled as is the space bar function key. Actuating many of these control functions also requires simultaneous multi-key actions. Striking keys on modern teleprinter and computer keyboards generates a single fixed length alpha-numeric, punctuation or control character symbol and providing no capability to send run-together (concatenated) variable length symbols like Morse prosigns. Additionally, many of the built in control characters of the modern character set codes generated by keyboards are unrelated to traditional variable length Morse prosigns. Because of this, Morse operators using keyboard operated computer applications often encounter difficulties attempting to send correctly formed Morse prosign symbols and may also encounter incorrectly formed (non-concatenated) prosign symbols sent by other keyboard operators.

An example of the difficulties encountered by Morse operators using keyboards rather than telegraph keys to send Morse prosigns is the use of the keyboard key labelled either "Enter" or "Newline". Depending upon the application, striking the "Enter" or "Newline" key produces the same result as the older Carriage return, Line Feed (CR-LF) key sequence which typists execute manually on teleprinter or typewriter keyboards. The common multiple key (CR-LF) manipulations used with teleprinters and typewriters has the same effect on printed text formatting as the traditional Morse new line AA prosign symbol sequence ( · — · —). Unfortunately most computerized Morse applications do not generate the Morse prosign AA when the "Enter"" or "Newline" key is struck, and most current Morse computer applications do not respond to the Morse AA prosign by generating a Newline. The same is true for many of the other Morse prosign symbols such as the new paragraph prosign BT and the new page or message separator prosign AR. Corresponding single keys for most traditional Morse prosigns are not found on modern computer and teleprinter keyboards. Operators who choose to use most keyboard operated computerized Morse software applications should realize that keying characters in sequence does not concatenate them. For example, keying the character B followed by the character T will not generate the traditional Morse prosign BT. As noted in following paragraphs explaining the Table of Morse prosigns, to alleviate some of these difficulties certain keyboard operated computerized Morse applications and products using single-line displays have hijacked a couple of mathematical symbol keys on modern keyboards (e.g. "+" and "=") which are used to represent two of the traditional Morse prosigns in those particular application devices.

Because of these computer keyboard Morse software application limitations and omissions, operators sending Morse from keyboard controlled applications rather than telegraph keys will encounter difficulties creating traditional Morse prosigns. Keyboard Morse operators may work around these difficulties by connecting a standard telegraph key into the keying line beside the computer keyboard application interface and intervene during keyboard sending by manually operating the standard telegraph key to transmit traditional prosigns. This workaround however defeats the convenience of using a modern keyboard. None of these difficulties actually prevents the development of Morse software applications capable of sending traditional Morse prosigns. For example, application developers might utilize one or more of the anonymously named function keys labeled: "F1", "F2", etc. to actuate traditional Morse prosigns under program control. Likely because of the limited commercial market for such application programs, this currently does not seem to be the case. And so, keyboard Morse operators may be unable to correctly send most traditional Morse code prosigns and may hear improperly formed (non-concatenated) prosigns sent by keyboard Morse operators. When acquiring or purchasing keyboard operated computerized Morse software applications users should determine if the application appropriately handles Morse prosigns for their needs.

Fluent Morse code telegraphers enjoy sending Morse code and traditional Morse prosigns using manually operated mechanical telegraph keys or electronic keyers. Aspiring high speed fluent Morse operators must not only master standard Morse alpha-numeric and punctuation symbols but must also master the use of traditional Morse prosigns as described in the following Table and explanatory paragraphs.

Table of Morse prosigns and useful Morse code abbreviations[edit]

The following Table lists twelve unique Morse prosigns and two useful Morse code abbreviations, ordered alphabetically. Although each prosign symbol dot/dash sequence is unique, the delimited character groups listed in the first column of the Table are only the most common concatenated character group representations for these unique prosigns. In fact different groups of concatenated characters may represent the same unique prosign. Apart from the two Morse code abbreviations BK and CL listed, the delimited concatenated characters in the first Table column are generally not abbreviations and have no intrinsic meaning, they are shown strictly for illustrative and alphabetic indexing purposes. When forming prosigns by telegraph key the delimited group characters are separated by only one dot duration, not the normal Morse three dot duration inter-character spacing. The dot/dash sequences shown in the second column titled Code Symbol comprise the unique dot/dash sequence definition of each prosign. Apart from the two Morse code abbreviations BK and CL which are not complete stand alone symbols but are comprised of their constituent character symbols, the Morse prosign symbols have their own complete stand alone unique sound that is distinctly different from the sounds of all other Morse characters and symbols. In order to handle Morse prosigns at high speed, the unique symbol sounds, illustrated in the Table column labeled Verbalization, must be memorized. The single exception to the uniqueness of prosign symbols is the alphabetic character "K" which is used both as an alphabetic character symbol and alternatively as a prosign symbol. The normal alphabetic character "K" is interpreted as a prosign and not an alphabetic character only when sent alone at the end of a transmission. In practice the two useful Morse code abbreviations BK and CL exhibited in the Table may be occasionally encountered as concatenated characters. Normally however the two acronyms BK and CL are sent and decoded as Morse code abbreviations, represented by their separate alphabetic characters and sounds, rather than as strict complete stand alone unique prosign symbols having unique symbol sounds.

Table of Morse Code Prosigns and Useful Morse Code Abbreviations [1]
Prosign Code Symbol Meaning Comments Memory Aid Verbalization
AA ·-·- New Line (space down one line) Typewritten as Carriage Return, Line Feed (CR-LF). "Add A line" "didahdidah"
AR ·-·-· New Page (space down several lines) Message separator. Single-line display may use printed “+”. "All Rendered" "didahdidahdit"
AS ·-··· Wait Respond with: SN, or characters "R" (Roger) or "C" (Confirm). "Wait A Sec" "didahdididit"
BK -··· -·- Break (Morse abbreviation) Back-to-you. Initiates a turn over between two stations. "BreaK" "dahdididit dahdidah"
BT -···- New Paragraph (space down two lines) Typewritten CR-LF-LF. Single-line display may use printed "=". "Begin Two" "dahdidididah"
CL -·-· ·-·· Closing (Morse abbreviation) Station closing. "CLosing" "dahdidahdit didahdidit"
CT -·-·- Attention Sometimes written as KA. Commencing important transmission. "Copy This" "dahdidahdidah"
HH ........ Error (Sometimes "????" is used.) Sometimes written EEEEEEEE. Always followed by correct text. "Error" "didididididididit"
K -·- Invitation for any station to transmit Lone alphabetic character "K" at the end of a transmission. "OK, go ahead" "dahdidah"
KN -·--· Invitation for named station to transmit Go ahead, specific named station. "OK, Named" "dahdidahdahdit"
NJ -··--- Shift to Wabun code Shift from Morse code to Wabun code Kana characters. "Next Japanese" "dahdididahdahdah"
SK ···-·- End of contact Sometimes written as VA. "Silencing Key" "didididahdidah"
SN ···-· Understood Often written VE. Alternatively shift from Wabun to Morse code. "Sho' 'Nuff" "didididahdit"
SOS ···---··· International distress signal Signals imminent danger to life or property. (About this sound listen ) "Save Our Souls" "didididahdahdahdididit"

Attention prosigns: CT and SOS[edit]

In Morse code the so-called attention prosigns are used to attract the attention of all stations that may be monitoring or listening to a communications channel.

The attention prosign CT is used when a transmitting station wants all monitoring stations to be alert and to listen carefully for an imminent important message or transmission. Upon hearing CT receiving stations should be prepared to copy down or record everything that follows. CT may be interpreted in English as, "Copy This".

The distress prosign SOS is the International Morse code distress signal to be used ONLY in EMERGENCY situations to draw immediate attention and to request immediate help either to save lives or to protect the imminent destruction of significant property. SOS may be interpreted in English as "Save Our Souls".

Since early in the 20th century (Radio Act of 1912), the radio frequency of 500 kiloHertz (500 kHz) has been an international calling and distress frequency for Morse code maritime communication. Prior to the adoption of the distress prosign SOS as an International Morse distress signal in the early 1900s, the Marconi Company used the signal CQD as a Morse distress signal. The distress signal CQD was not a prosign per se, rather it was a special Marconi code signal comprising the separate non-concatenated characters C, Q and D. The use of CQD was phased out in favor of SOS around the time of the RMS Titanic sea disaster and now for over one hundred years, the Morse prosign SOS has been used under several issues of the Safety of Life at Sea or SOLAS Convention regulations as a world-wide International Morse code distress signal. Under pain of criminal offense for misuse, the transmission of the SOS prosign is only permitted to attract attention when life or property is endangered. In this regard the Morse code SOS prosign has the same significance as the Mayday distress signal used with voice communications by radio.

White space prosigns: AA, BT and AR[edit]

With formal written Morse messages white spaces are the line spaces appearing on a page delineating either: a new line, a new paragraph or, a new page (or message separation). Unlike informal Morse conversation, with formal written message procedures the three Morse prosigns AA, BT and AR are used on transmission to indicate the presence of and, on reception, to initiate the creation of, white space formatting of the written or printed text on the: page, computer text file, or video screen where the message is displayed.

With informal Morse conversations, which are often carried out mentally rather than formally written, the new paragraph BT prosign is typically only used to provide operators with brief pauses for gathering their thoughts, and to perhaps jot down short notes. Such informal Morse conversations are often referred to as copying code in the head.

Although the message separator prosign AR is quite often used informally by amateur radio operators, its use is unwarranted in casual informal Morse conversations. The message separator prosign <AR> is superfluous to informal Morse conversations unless the information being transmitted actually requires explicit inter-message separation to enhance understanding and message handling.

Upon reception by telegraphers, these three white space prosigns AA, BT and AR enable the creation of highly human legible documents.

The formal use of these three prosigns in creating white space document legibility is detailed as follows.

The new line prosign AA indicates a new line (space down one line).

The new paragraph prosign BT indicates a new paragraph (space down two lines).

The end of message prosign AR indicates a message separator (space down several lines or, create a new page or, initiate a Form Feed).

Historically formal record traffic Morse messages were typewritten in high volumes by professional telegraphers onto long paper rolls, or fan folded, page serrated, paper stacks, which were fed through typewriters rather than having telegraphers continually insert separate sheets or pages into the typewriter to accommodate each message. Multiple messages were often sent by traffic handlers during long traffic transmission sessions and efficient work flow demanded formal separation of messages in transmissions by the AR prosign and sufficient message separation white space on paper to enable physically tearing apart messages for actual delivery to third parties on reception. Historically the message separator prosign AR indicating end of message was used to initiate the creation of this inter-message white space on the page (space down several lines, space down to a new page or initiate a Form Feed). Telegraphers often turned up a completely new page on the continuous paper roll feed for each message. Some kinds of teleprinter and computer printer documentation refer to this kind of white space page creation as a Form Feed (FF). When typing or writing on individual message forms such as the ARRL Radiogram form a new blank message form is actually torn from a pad of blank forms upon hearing the AR prosign. The prosign AR may thus be interpreted as a message separator between messages or as the end of message marker on a per message basis or as a Page break or Form Feed on equipment with form feed capability.

Early telegraphers apparently saw the need for, and created, only the three white space prosigns AA, BT and AR described previously. On the other hand, modern computer character set codes and keyboards contain even more white space control characters such as the space bar, the Tab key and the so-called Form Feed key. The space bar on modern keyboards creates the standard fixed space between words and generates the most widely used teleprinter and computer keyboard white space control character symbol sometimes known as the blank character. Since traditional Morse code symbols are of variable width there can be no Morse prosign equivalent to the fixed length white space blank character symbol created by the space bar. Traditional telegraphers create space bar white space blank characters between words by simply pausing for the minimum number of prescribed dot durations (normally seven) required for Morse code inter-word spacing. Although there is no Morse code equivalent for the Tab function key of modern keyboards, the Morse prosign AR may be considered equivalent to the Form Feed key on some keyboards.

The unwritten Morse code white space prosigns AA, BT and AR enable the creation of highly human legible documents by enabling the visual arts use of white space to enhance human document reading and predates the use of the somewhat arcane in-line printed mathematical symbols implemented by some microcomputer based single-line display Morse encoder/decoder products.

Keyboard math symbols used to generate BT and AR[edit]

Normal page oriented white space line space formatting cannot be used with single-line electronic display systems since it is impossible to space down page on non-existent pages to create white space lines on a single-line display. Sometimes keyboard operated systems utilizing single-line displays instead generate or render the new paragraph prosign BT using the mathematical "=" symbol found on keyboards and generate or render the message separator prosign AR using the mathematical "+" symbol found on keyboards.

Apparently the representation of the (normally unwritten) new paragraph BT and message separator AR prosigns by means of the seldom used mathematical "=" and "+" symbols and keys initially appeared with the advent of keyboard operated electronic Morse code encoder/decoder devices utilizing single-line displays. Examples of such devices are the MFJ Enterprises models MFJ-461 and MFJ-462B microprocessor based Morse code reader products.

Since traditional white space formatting of pages according to the received (unwritten) prosigns creates more human legible documents than computer based methods that utilize in-line insertion of printed mathematical symbols (=, +), Morse code software application developers should include an option allowing users to select either, the traditional highly legible white space formatting or, at the user's discretion, the arcane computer oriented in-line printed mathematical (=, +) symbols.

Turn over prosigns: K, KN, SK and abbreviations: BK and CL[edit]

Turning over a communications channel is the change in communications protocol transmission status that occurs when a transmitting station turns over or releases transmitting control of a communications channel to another station.

The general turn over prosign K although not a unique symbol is traditional and is identical to the alphabetic character symbol for the letter "K". K is interpreted as a prosign only when sent alone at the end of a transmission. This symbol is the only prosign symbol that is identical to another Morse symbol, namely the normal written text alphabetic character "K". When sent alone at the end of a transmission the alphabetic character symbol for the letter "K" (verbalized as "dahdidah") is taken as a prosign to indicate a general channel turn over change in communications protocol status. The prosign K literally means "ok, go ahead anyone" or "ok, over to anyone".

The specific turn over prosign KN comprised of the run-together or concatenated letters K and N indicates a specified channel turn over or change in communications protocol status literally meaning "go ahead only" or "over to you only" when the sending operator wishes a reply from only the currently specified receiving station and does not wish replies from any other stations.

The end of contact turn over prosign SK is usually sent in lieu of the prosign K or the prosign KN at the very end of the last transmission from the transmitting station to indicate the termination or end of a particular contact (conversation) between two stations, thus turning the communications channel over to other users. The SK prosign may be interpreted in English as, this station will be "silencing key". Often when terminating a contact with the SK prosign a transmitting station may continue listening on the communications channel for calls from other stations.

The back-to-you turn over Morse code abbreviation BK is actually an abbreviation for the word "break" comprising the sequential alphabetic letters B and K which are not run-together and is sometimes used within a Morse conversation or contact between two stations as a turn over abbreviation to indicate that the sending station is turning over the communications channel to the specific receiving station without taking the time to transmit the identity of either the sending or receiving station. Generally fluent high speed Morse operators tend not to use the BK abbreviation for channel turn overs, instead using the full break-in or QSK operation interrupt technique for turn overs as outlined in a following paragraph.

The closing station turn over Morse code abbreviation CL is actually an abbreviation for the word "closing" comprising the sequential alphabetical letters C and L which are not run-together and is sometimes sent by operators as their last signal before closing their station by finally quitting the communications channel, and turning off their receivers. For example, when terminating a contact and closing their station, a transmitting station will often end the last transmission with the sequence SK CL which can be interpreted in English as, "silencing key and closing".

Full break-in turn over, also known as QSK operation,[3] is the fastest and most efficient Morse code turn over technique. QSK operation is a technique wherein each station is equipped with the radio transceiver hardware technology necessary to enable listening between transmitted dots and dashes. This so-called QSK hardware technology creates the opportunity for a receiving station to quickly interrupt a sending station in mid-transmission. Station operators equipped for full break-in operation usually send the Q code signal QSK during the first transmission of a Morse conversation to inform the receiving operator that the transmitting operator can listen between dots and dashes. When equipped for full break-in (so-called QSK operation) stations can easily interrupt each other's transmissions by momentarily pressing their telegraph key while the other station is still transmitting. At this point the interrupted station pauses and transmits a single prosign K indicating that the channel has been turned over, and pauses again to listen for what the interrupting station sends next. Using hardware enabled full break-in interrupt technology (QSK) together with the single Morse prosign K enables fast and fluid two-way telegraphy communications similar to normal human face-to-face voice conversations.

As with all Morse code prosigns, in practice none of these turn over abbreviations and prosigns are ever written or printed by receiving operators.

Miscellaneous prosigns: AS, SN and NJ[edit]

The wait prosign AS is used by a transmitting station to request that receiving stations wait for further instructions from the transmitting operator. Often the prosign AS may be immediately followed by a numeric character such as AS 1 or AS 3 to indicate the approximate number of minutes (here, one or three minutes) that the sending operator wishes the receiving operator to wait. The wait prosign is often used by Morse code amateur radio net control operators when acknowledging specific stations checking into a Morse code network. Normally the receiving station being asked to wait will immediately respond to an AS request by sending the single understood prosign SN.

The understood prosign SN is intended to be used by receiving operators to respond to requests from a transmitting operator. For example, a transmitting operator may request the receiver to wait for three minutes by sending AS 3 and the receiving operator would respond immediately with the single prosign SN. In practice however many Morse code operators will more commonly acknowledge requests with a single ordinary alphabetic character "R", which is a short form of the voice response "Roger" or "Received" or with the single alphabetic character "C" which is a Morse code short form for "Confirmed" or "yes". (Note that the letter "C" sounds like the Spanish word "si" for "yes".)

The next Japanese prosign NJ, when sent by a Morse code operator indicates to the receiving operator that the sending operator will be immediately shifting the communications protocol from International Morse code symbols to Japanese Wabun code Kana symbols and to interpret all of the symbols that follow as Wabun code symbols and not Morse code symbols. The symbol NJ may thus be interpreted in English as "Next Japanese". Prosign NJ may also be shown as DO.

The prosign SN appears in both Morse where it means understood and in the Wabun code where it means shift to Morse code. When sent by a Japanese Wabun code operator, SN is a prosign symbol in the Japanese Wabun code that indicates to the receiving operator that the sending operator will be immediately shifting the communications protocol status from the Japanese Wabun code Kana character symbols to International Morse code encoding and to interpret all the symbols that follow as International Morse code and not the Japanese Wabun code Kana symbols.

The Wabun code is a special form of dot/dash symbol code created by the Japanese, which encodes the Japanese Kana (Hiragana or Katakana) characters. The two prosigns SN and NJ (the latter often written as DO) are used to signal a communications protocol status change (shift) from the Japanese Wabun code to Morse code and vice versa. Note that the Kana characters are a phonetic form of writing Japanese language and do not include the thousands of ideographic Kanji characters used in Chinese, Japanese, and Korean writing.

Error prosign: HH[edit]

The error prosign symbol HH[4] indicates a previously sent error and is comprised of a series of eight concatenated dots[5] or run-together alphabetic letter "E" symbols. This error prosign symbol indicates an accidental error in transmission that, once sent, has been almost immediately recognized by the sending operator. When the error prosign HH is sent it is immediately followed by the corrected information text, usually resending the entire current word. When formally writing or typing a message, the receiving operator then deletes (or crosses out) the erroneous text and replaces it with the corrected text.

For illustrative or instructive purposes this symbol may be written or shown as eight run-together "E" letters with overline as EEEEEEEE, or as the shorter delimited form HH. This HH error prosign is never written down by receiving operators; it signals an upcoming correction to the previously transmitted message text, i.e. a change in communications protocol status.

Other non-prosign techniques are sometimes informally used to indicate such accidental errors in transmission. Some operators indicate errors by sending a few sequential question marks (e.g. ????), a sequence which would not often normally appear in regular written text messages. The sequence of four or more question punctuation marks is then followed by the correct text. Alternatively some operators indicate an accidental sending error by transmitting a few well spaced-out dots, the unusual "broken" rhythm indicating that an error was accidently sent and then followed by the correct text.

In formal message traffic handling there are a further set of detailed procedures and abbreviations for locating errors and getting fills (making corrections) within formal messages which, for those interested, are fully described in the message handling documentation found in the ARRL Radiogram ARRL National Traffic System (NTS) practices and procedures documentation. This documentation is available in print or on line from the American Radio Relay League (ARRL).

Prosigns in casual use[edit]

Unlike formal written record message handling or participation in either Morse code tests or Morse code high speed copying contests, casual conversations or contacts between amateur radio operators do not require memorizing all of the prosigns or attaining great skill in use of all of the twelve prosigns and two abbreviations in the preceding Table. This is because, with most casual amateur radio contacts, the full text of conversations is usually never written down or recorded. Instead operators casually copy Morse signals mentally while jotting down only a few important facts such as names and locations, etc. With such casual contacts, there is no need for white space formatting prosigns, or initiating specific message handling communications protocol changes.

Of the twelve prosigns listed in the preceding Table, only three, namely: K used to turn transmission control over to other parties, BT used to provide pauses between thoughts and HH the error prosign, are all that are necessary for use in casual Morse code conversations or contacts.

With a little more experience the use of the KN and SK prosigns and the use of the two abbreviations or acronyms BK and CL can be entertained. Finally, just in case there is ever an emergency encounter during operations, the sound of the SOS prosign should be memorized.

And so for casual amateur radio Morse code operation, only six prosigns namely: K, BT, HH, KN, SK, SOS of the twelve Morse prosigns and the two abbreviations BK and CL tabulated in the preceding Table need ever be committed to memory. The remaining six prosigns of the preceding Table can be safely left to professional/commercial or hard core amateur radio telegraphy message traffic handlers who actually handle formal written record messages.

Example telegraphy conversation with prosigns[edit]

Sensible and efficient informal Morse code conversations between operators involves more than simply knowing the alpha-numeric and punctuation characters.

Skilled operators must at least also know and respond to at least seven common Morse code prosign symbols. In addition to Morse code characters and prosign symbols there are also internationally agreed communications protocols or patterns of communication, international Morse code abbreviations, and codes such as the: ACP-131 brevity codes: the Q code, Z code, RST code and commonly encountered numbers from older telegraph era codes such as the Phillips Code to assist with efficient and quick Morse code conversations.

In the following example an informal Morse code conversation between stations with the call signs X1AA and X2BB is depicted.[6] In the following conversational example the mathematical symbol "=" representing the prosign BT is shown written in-line as might occur if a single-line display automated software application were encoding and/or decoding the Morse code. The prosign symbol BT is actually sent (verbally this prosign is rendered as "dahdidididah") along with the other Morse code information bearing characters but these prosigns are not normally written down by the receiving operator. If writing while copying the signal the receiving operator merely skips down a line or two upon hearing the BT prosign creating the appropriate white space.

Often, as depicted in the following example, with short informal Morse code conversations operators 'copy' mentally in their heads without formally writing or typing anything. In the case of mental copy the presence of the BT prosigns, indicated by the "=" signs in the following example, instead of being used to trigger white space in a written record, are used to simply provide the receiving operator with a short mental pause to digest what was just sent, and perhaps to jot down a short note about it.


Calling anyone (CQ), this is (DE) X1AA, over, go ahead anyone (K)


Calling X1AA, this is X2BB, back-to-you only. (KN means you are inviting only the named party to reply)


We note here again, the "=" signs represent the BT prosigns as e.g. in single-line display computerized Morse readers.
Good afternoon dear old man you are RST 599 here
(Note - RST 599 means... Very readable (5), very strong signal (9), very good tone (9))
I'm located in Timbuktu (QTH)
The operator is John
How do you copy? Go ahead only X2BB.


Thanks for the fine business report dear old man John. I read you 558.
(RST 558 means - Very readable (5), adequate, low-strength signal (5), good tone (8))
I am in the Himalayas (QTH)
My name is Yeti, go ahead anyone (K).
(Note sending K alone as a prosign without the run together N invites other callers to break in).


Okay, thanks (for this) conversation QSO) dear Yeti
Best regards (73) Phillips Code and hope to see you again. Go ahead anyone.


Roger (R) thank you see you again best regards (73). Signing off (silencing key) .(SK)


Often, a couple of dits might end an amateur radio Morse conversation or contact. This traditional Morse code idiom resembles the archaic English "pip pip".

X1AA and X2BB are representative amateur radio call signs identifying each of the parties to the Morse code conversation or contact.

This example conversation, with channel turn overs initiated only by transmitting stations sending the K or the KN prosigns between transmissions is slow, awkward, and stilted when compared to normal face-to-face two-way voice conversations where the parties can actually interrupt each other.

Full break-in or QSK operation is a hardware supported turn over technique that enables less stilted Morse conversations than illustrated by the preceding example and facilitates a style of communications protocol similar to normal human face-to-face conversation.

This QSK operation comprises a technology and protocol wherein each station is equipped with the hardware capability of listening between dots and dashes thus enabling interruptions by the other party similar to face-to-face voice conversations. If both parties are equipped with fast transmit/receive (T/R) radio frequency switching hardware for full break-in interrupted operation, stations may break into (interrupt) another's transmission at any time by momentarily pressing their telegraph key. Upon hearing the break-in signal the interrupted station simply stops sending and transmits a single K prosign indicating go ahead and then listens for the interrupting party to make their transmission.

Using full break-in high speed transmit/receive switching technology (QSK) to enable stations to interrupt each other when used together with the turn over prosign K creates a communications channel turn over protocol that facilitates a smooth, fluid style of Morse code conversation that is as efficient as face to face voice communications. Unfortunately not all radio transceiver equipment provides the high speed hardware transmit/receive (T/R) radio frequency switching support necessary for QSK full break-in operation. Generally full break-in capability is only available on more expensive radio transceivers. Radiotelegraphers who aspire to this QSK mode of Morse conversation must ensure that the radio equipment they acquire or construct includes the hardware ability for T/R switching fast enough to allow listening between the dots and dashes.

Example formal telegraphy message with prosigns[edit]

Traffic handlers are Morse code operators who: originate, send, receive, relay, record and deliver – or handle — so-called formal recorded text messages for relay and ultimate delivery to third parties. Morse record traffic handlers may be radio amateurs[3] or paid professionals such as ship's radio operators or military radio operators who send or relay radiograms on behalf of third parties. Regulations often require that a record of third party traffic be retained by the sending and relaying stations for a reasonable period, hence such formal third party messages are often called record traffic. These formal records of third party traffic radiograms are usually hand written, or typewritten, either on paper or typewritten into a word processing file so that a more or less permanent record of the radiogram is available to be kept on file for future reference in case authorities wish to review the record traffic for their legal requlating purposes.

In North America (United States and Canada) amateur radio operators (hams) are permitted to handle such third-party record traffic as a nonprofit public service. Such traffic handling on behalf of third parties by amateurs is actually forbidden by law or regulation in much of the rest of the world outside of the Americas where most message relay service has been reserved for government authorized monopoly licensed corporations or governmental agencies such as local PTT authorities (postal, telegraph and telephone service). The United States national ham radio organization known as the American Radio Relay League (ARRL), and its Canadian counterpart, Radio Amateurs of Canada (RAC), publish manuals that standardize traffic handling procedures for such third party record communications. These manuals may be downloaded from links at the ARRL Internet Web site under the subject National Traffic System or NTS. The word Relay in the name of the ARRL is a relic of the original organizational purpose (third party message relay) of the American Radio Relay League.

When Morse code record traffic handlers receive a formal record message for relay or for ultimate delivery to a third party they do not write or type prosigns explicitly, instead they take the page and text formatting or transmission communications protocol actions indicated by the Morse prosigns to format the recorded message on the page, text file, or video screen. For example, when hearing the attention prosign CT ("Copy This") the operator who, until hearing the CT prosign, is merely listening without writing or typing, will begin writing or typing all that comes after the CT prosign, immediately expecting a text message header to follow.

When hearing BT ("Begin Two lines") within a message, the traffic handler creates white space by beginning a new paragraph on the page (e.g. spaces down two lines). When hearing the prosign AA within a message, the traffic handler spaces down one line on the page (i.e., starts a new line, say for each line of a street or postal address). Upon hearing the prosign AR the operator stops writing down or recording the current message text and prepares a new page (or a new message blank from a pad of ARRL Radiogram blanks) or just spaces down several lines to a new part of the page in preparation to copy a subsequent message.

An example of a typical record traffic message, sent in the ARRL Radiogram format,[7] first as heard by the operator, illustrated in the following part A paragraph which explicitly includes all prosigns that are included in the data stream as well as the record text and, secondly in the following part B paragraph which illustrates the message as actually recorded by writing or typing the message on paper or into an electronic text file, without explicitly written prosigns. The second Part B paragraph illustrates the appropriate white spaces created by the receiving operator in response to the white space, attention and message separator prosigns sent by the transmitting operator.

Part A: --- Morse code message data stream as actually transmitted, including prosigns. ---


Part B: --- Message as recorded (typed) on paper with white space text formatting rendered in accordance with the received prosigns. ---

NR 2 R HXE VE9ZK 10 OTTAWA 1800 12-23-14

INDIA, FL 32900



The two layouts of the same message as exhibited in the preceding paragraphs illustrates: In Part A - the continuous data stream of Morse code symbols as received in real time and, In Part B - the white space formatted text message as recorded in more human legible form on the: page, text file, or electronic display where the permanent record of the message will be stored for future use.

The first line in this formal message is the so-called header and contains somewhat arcane details of ARRL Radiograms that are only of interest to record traffic handling experts. The address lines illustrated below the header line are separated by two lines from the header as indicated by a new paragraph BT symbol prosign. Each line of the address information is separated from the others by a one line space indicated by the new line AA prosign symbols. The address is then separated from the main text of the message by a two line space new paragraph symbol BT. Finally the signature line "PETE" is separated from the main body of the text by two lines indicated by another BT prosign.

Comparing the two message layouts illustrated under the preceding Part A and Part B paragraphs, readers will note that the protocol change prosigns CT and AR in the Morse code data stream of Part A indicate only changes in transmission protocol status and so do not explicitly appear in the part B recorded message layout. The leading prosign CT, usually interpreted as "Copy This", alerts the operator to pay attention and to begin writing or recording a new message text. The message separator prosign AR sent at the end of the message is interpreted as "End of Message" or "New Page", and alerts the operator to stop writing or typing message text and to prepare a new page or a new place on the page (by creating enough white space separation) for the next message.

Readers may note the traditional ARRL Radiogram style use of an "X" character in the main text of the formal message to indicate a so-called full stop which is equivalent to the period punctuation mark. Traditionally, standard punctuation mark characters such as: commas, periods and question marks are not used in Morse traffic handling, instead such punctuation marks are simply spelled out as words to ensure accuracy under noisy communications conditions. Sometimes the period or full stop may be sent as the spelled out word STOP rather than the letter "X". It is also traditional in Morse code record traffic to spell out the word QUERY in place of the punctuation mark symbol "?".

Normally highly skilled Morse traffic handlers operate using full break-in or QSK operation and so the operators sending the radio telegram messages as presented in the preceding Part A and Part B paragraphs are actually listening for possible interruptions from the receiving station as they are sending. The receiving operators may then interrupt the sending operator at any time during sending of the telegram message by hitting their telegraph key allowing them to immediately correct errors or obtain 'fills' for parts of the message they may have missed. Further details of traditional efficient Morse code record traffic ARRL Radiogram handling procedures and practices may be found in the ARRL National Traffic System (NTS) documentation which is available in print or on line from the American Radio Relay League or ARRL.

See also[edit]


  1. ^ a b ARRL Inc. (8 October 2012). ARRL Operating Manual (10 ed.). ARRL. ISBN 978-0872595965. 
  2. ^ a b
  3. ^ a b
  4. ^ ARRL FSD-218
  5. ^ ITU-R M.1677-1 recommendation
  6. ^ Field, Don (2010). The Amateur Radio Operating Manual. Potters Bar: Radio Society of Great Britain. p. 92. ISBN 1-905086-00-8. 
  7. ^