Q code
Encyclopedia
The Q code is a standardized collection of three-letter message encodings, also known as a brevity code
, all of which start with the letter "Q", initially developed for commercial radiotelegraph communication, and later adopted by other radio services, especially amateur radio
. Although Q codes were created when radio used Morse code
exclusively, they continued to be employed after the introduction of voice transmissions. To avoid confusion, transmitter call sign
s are restricted; while an embedded three-letter Q sequence may occur (for instance when requested by an amateur radio station dedicated to low-power operation
), no country is ever issued an ITU prefix
starting with "Q". The codes in the range QAA–QNZ are reserved for aeronautical use; QOA–QQZ for maritime use and QRA–QUZ for all services.
government
as a "list of abbreviations... prepared for the use of British ships and coast stations licensed by the Postmaster General". The Q codes facilitated communication between maritime radio operators speaking different language
s, so they were soon adopted internationally. A total of forty-five Q codes appeared in the "List of Abbreviations to be used in Radio Communications", which was included in the Service Regulations affixed to the Third International Radiotelegraph Convention in London (The Convention was signed on July 5, 1912, and became effective July 1, 1913.)
The following table reviews a sample of the all-services Q codes adopted by the 1912 Convention:
s were banned in the United States in the 1920s, rendering the original meaning of those Q codes obsolete. Over a hundred Q codes were listed in the Post Office Handbook for Radio Operators in the 1970s and cover subjects such as meteorology, radio direction finding, radio procedures, search and rescue, and so on.
Some Q codes are also used in aviation
, in particular QNH
and QFE, referring to certain altimeter settings. These codes are used in radiotelephone conversations with air traffic control
as unambiguous shorthand, where safety and efficiency are of vital importance. A subset of Q codes is used by the Miami-Dade County, Florida
local government for law enforcement and fire rescue communications, one of the few instances where Q codes are used in ground voice communication.
The QAA–QNZ code range includes phrases applicable primarily to the aeronautical service, as defined by the International Civil Aviation Organisation. The QOA–QQZ code range is reserved for the maritime service. The QRA–QUZ code range includes phrases applicable to all services and is allocated to the International Telecommunications Union. And QVA–QZZ are not allocated. Many codes have no immediate applicability outside one individual service, such as maritime operation (many QO or QU series codes) or radioteletype
operation (the QJ series).
Many military and other organizations that use Morse code have adopted additional codes, including the Z code
used by most European and NATO countries. The Z code adds commands and questions adapted for military radio transmissions, for example, "ZBW 2", which means "change to backup frequency number 2", and "ZNB abc", which means "my checksum is abc, what is yours?"
Used in their formal "question/answer" sense, the meaning of a Q code varies depending on whether or not the individual Q code is sent as a question or an answer. For example, the message "QRP?" means "Shall I decrease transmitter power?", and a reply of "QRP" means "Yes, decrease your transmitter power". This structured use of Q codes is fairly rare and now mainly limited to amateur radio and military morse code (CW) traffic networks.
s. In December, 1915, the American Radio Relay League
began publication of a magazine titled QST
, named after the Q code for "General call to all stations". In amateur radio, the Q codes were originally used in Morse code transmissions to shorten lengthy phrases and were followed by a Morse code question mark (··--··) if the phrase was a question.
Q codes are commonly used in voice communications as shorthand nouns, verbs, and adjectives making up phrases. For example, an amateur radio operator will complain about QRM (man-made interference), or tell another operator that there is "QSB on the signal"; "to QSY" is to change your operating frequency.
Some of the common usages vary somewhat from their formal, official sense. QRL? is the accepted form of the question, "Is this frequency in use (or busy)?", the reply to which is typically the letters "C" (dah di dah dit
), "R" (di dah dit
) or "Y" (dah di dah dah
) which, in the Amateur radio tradition, are the Morse code shorthand for "Confirm", "Roger" or "Yes." There are also a few unofficial and humorous codes in use, such as QLF ("try sending with your LEFT foot") and QSC ("send cigarettes", not the official meaning of "this is a cargo vessel"). In the question form, QNB?, is supposed to mean "How many buttons does your radio have?" A reply of the form QNB 45/15 means "45, and I know what 15 of them do." QSJ is sometimes used to refer to the cost of something - "I would like an FT9000 but it is too much QSJ". (QSJ actually means "What is the charge to be collected to ... including your internal charge?").
QSK - "I can hear you during my transmission" - refers to a particular mode of Morse code operating in which the receiver is quickly enabled during the spaces between the dits and dahs, which allows another operator to interrupt transmissions. Many modern transceivers incorporate this function, sometimes referred to as full break-in as against semi-break-in in which there is a short delay before the transceiver goes to receive.
A conversation or contact via amateur radio is often referred to as a QSO, while QSL
cards are collected by both radioamateurs and shortwave
listeners as confirmation of having received the signal of a particular station.
Regarding the speed of the Morse code being sent, if the speed is too fast and the receiving operator cannot copy the code at said speed, that operator may send "QRS", the request to "please slow down." A courteous sender will slow down to match the speed of the slower operator.
QTHR - "at the registered address for my callsign", this is used mainly in the United Kingdom and former colonies. Since business may not be discussed on amateur radio, a ham who has personal equipment to sell might say something like "I have a spare Morse key old chap, please contact me QTHR".
Note: The ARRL codes QNA-QNZ overlap with International Civil Aviation Organization (ICAO) codes but have different meanings.
Royal Air Force: QGH signified "Controlled Descent through Clouds"
Brevity code
Multiservice tactical brevity codes are codes used by various military forces. The codes procedure words, a type of voice procedure, are designed to convey complex information with a few words.-American/NATO codes:...
, all of which start with the letter "Q", initially developed for commercial radiotelegraph communication, and later adopted by other radio services, especially amateur radio
Amateur radio
Amateur radio is the use of designated radio frequency spectrum for purposes of private recreation, non-commercial exchange of messages, wireless experimentation, self-training, and emergency communication...
. Although Q codes were created when radio used Morse code
Morse code
Morse code is a method of transmitting textual information as a series of on-off tones, lights, or clicks that can be directly understood by a skilled listener or observer without special equipment...
exclusively, they continued to be employed after the introduction of voice transmissions. To avoid confusion, transmitter call sign
Call sign
In broadcasting and radio communications, a call sign is a unique designation for a transmitting station. In North America they are used as names for broadcasting stations...
s are restricted; while an embedded three-letter Q sequence may occur (for instance when requested by an amateur radio station dedicated to low-power operation
QRP operation
In amateur radio, QRP operation means transmitting at reduced power levels while aiming to maximize one's effective range while doing so. The term QRP derives from the standard Q code used in radio communications, where "QRP" and "QRP?" are used to request, "Reduce power," and ask "Should I reduce...
), no country is ever issued an ITU prefix
ITU prefix
The International Telecommunication Union allocates call sign prefixes for radio and television stations of all types. They also form the basis for, but do not exactly match, aircraft registration identifiers. These prefixes are agreed upon internationally, and are a form of country code...
starting with "Q". The codes in the range QAA–QNZ are reserved for aeronautical use; QOA–QQZ for maritime use and QRA–QUZ for all services.
Early developments
The original Q codes were created, circa 1909, by the BritishUnited Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
government
Government
Government refers to the legislators, administrators, and arbitrators in the administrative bureaucracy who control a state at a given time, and to the system of government by which they are organized...
as a "list of abbreviations... prepared for the use of British ships and coast stations licensed by the Postmaster General". The Q codes facilitated communication between maritime radio operators speaking different language
Language
Language may refer either to the specifically human capacity for acquiring and using complex systems of communication, or to a specific instance of such a system of complex communication...
s, so they were soon adopted internationally. A total of forty-five Q codes appeared in the "List of Abbreviations to be used in Radio Communications", which was included in the Service Regulations affixed to the Third International Radiotelegraph Convention in London (The Convention was signed on July 5, 1912, and became effective July 1, 1913.)
The following table reviews a sample of the all-services Q codes adopted by the 1912 Convention:
| Code | Question | Answer or Notice |
|---|---|---|
| QRA | What ship or coast station is that? | This is ____. |
| QRB | What is your distance? | My distance is ____. |
| QRC | What is your true bearing? | My true bearing is ____ degrees. |
| QRD | Where are you bound for? | I am bound for ____. |
| QRF | Where are you bound from? | I am bound from ____. |
| QRG | What line do you belong to? | I belong to the ____ Line. |
| QRH | What is your wavelength in meters? | My wavelength is ____ meters. |
| QRJ | How many words have you to send? | I have ____ words to send. |
| QRK | How do you receive me? | I am receiving well. |
| QRL | Are you busy? | I am busy. |
| QRM | Are you being interfered with? | I am being interfered with. |
| QRN | Are the atmospherics strong? | Atmospherics are very strong. |
Later usage
Over the years, modifications were made to the original Q codes to reflect changes in radio practice. In the original international list, QSW/QSX stood for "Shall I increase/decrease my spark frequency?", however, spark-gap transmitterSpark-gap transmitter
A spark-gap transmitter is a device for generating radio frequency electromagnetic waves using a spark gap.These devices served as the transmitters for most wireless telegraphy systems for the first three decades of radio and the first demonstrations of practical radio were carried out using them...
s were banned in the United States in the 1920s, rendering the original meaning of those Q codes obsolete. Over a hundred Q codes were listed in the Post Office Handbook for Radio Operators in the 1970s and cover subjects such as meteorology, radio direction finding, radio procedures, search and rescue, and so on.
Some Q codes are also used in aviation
Aviation
Aviation is the design, development, production, operation, and use of aircraft, especially heavier-than-air aircraft. Aviation is derived from avis, the Latin word for bird.-History:...
, in particular QNH
QNH
QNH is one of the many Q codes. It is defined as, "barometric pressure adjusted to sea level." It is a pressure setting used by pilots, air traffic control , and low frequency weather beacons to refer to the barometric setting which, when set on an aircraft's altimeter, will cause the altimeter to...
and QFE, referring to certain altimeter settings. These codes are used in radiotelephone conversations with air traffic control
Air traffic control
Air traffic control is a service provided by ground-based controllers who direct aircraft on the ground and in the air. The primary purpose of ATC systems worldwide is to separate aircraft to prevent collisions, to organize and expedite the flow of traffic, and to provide information and other...
as unambiguous shorthand, where safety and efficiency are of vital importance. A subset of Q codes is used by the Miami-Dade County, Florida
Miami-Dade County, Florida
Miami-Dade County is a county located in the southeastern part of the state of Florida. As of 2010 U.S. Census, the county had a population of 2,496,435, making it the most populous county in Florida and the eighth-most populous county in the United States...
local government for law enforcement and fire rescue communications, one of the few instances where Q codes are used in ground voice communication.
The QAA–QNZ code range includes phrases applicable primarily to the aeronautical service, as defined by the International Civil Aviation Organisation. The QOA–QQZ code range is reserved for the maritime service. The QRA–QUZ code range includes phrases applicable to all services and is allocated to the International Telecommunications Union. And QVA–QZZ are not allocated. Many codes have no immediate applicability outside one individual service, such as maritime operation (many QO or QU series codes) or radioteletype
Radioteletype
Radioteletype is a telecommunications system consisting originally of two or more electromechanical teleprinters in different locations, later superseded by personal computers running software to emulate teleprinters, connected by radio rather than a wired link.The term radioteletype is used to...
operation (the QJ series).
Many military and other organizations that use Morse code have adopted additional codes, including the Z code
Z code
Z Code is a set of codes used in CW, TTY and RTTY radio communication. Actually, there are different sets of Z-codes: one originally developed by Cable & Wireless Ltd., for commercial communications in the early days of wire and radio communications, another one independently developed by NATO...
used by most European and NATO countries. The Z code adds commands and questions adapted for military radio transmissions, for example, "ZBW 2", which means "change to backup frequency number 2", and "ZNB abc", which means "my checksum is abc, what is yours?"
Used in their formal "question/answer" sense, the meaning of a Q code varies depending on whether or not the individual Q code is sent as a question or an answer. For example, the message "QRP?" means "Shall I decrease transmitter power?", and a reply of "QRP" means "Yes, decrease your transmitter power". This structured use of Q codes is fairly rare and now mainly limited to amateur radio and military morse code (CW) traffic networks.
Breakdown by service
- QAA to QNZ - Assigned by the International Civil Aviation Organization (ICAO).
- QOA to QQZ - For the Maritime Services.
- QRA to QUZ - Assigned by the International Telecommunications Union (ITU).
Amateur radio
Selected Q codes were soon adopted by amateur radio operatorAmateur radio operator
An amateur radio operator is an individual who typically uses equipment at an amateur radio station to engage in two-way personal communications with other similar individuals on radio frequencies assigned to the amateur radio service. Amateur radio operators have been granted an amateur radio...
s. In December, 1915, the American Radio Relay League
American Radio Relay League
The American Radio Relay League is the largest membership association of amateur radio enthusiasts in the USA. ARRL is a non-profit organization, and was founded in May 1914 by Hiram Percy Maxim of Hartford, Connecticut...
began publication of a magazine titled QST
QST
QST is a magazine for amateur radio enthusiasts, published by the American Radio Relay League . It is a membership journal that is included in membership with the ARRL. The publisher claims that circulation of QST in the United States is higher than all amateur radio-related publications in the...
, named after the Q code for "General call to all stations". In amateur radio, the Q codes were originally used in Morse code transmissions to shorten lengthy phrases and were followed by a Morse code question mark (··--··) if the phrase was a question.
Q codes are commonly used in voice communications as shorthand nouns, verbs, and adjectives making up phrases. For example, an amateur radio operator will complain about QRM (man-made interference), or tell another operator that there is "QSB on the signal"; "to QSY" is to change your operating frequency.
Q codes applicable for use in amateur radio
| Code | Question | Answer or Statement |
|---|---|---|
| QRA | What is the name (or call sign) of your station? | The name (or call sign) of my station is ... |
| QRG | Will you tell me my exact frequency (or that of ...)? | Your exact frequency (or that of ... ) is ... kHz (or MHz). |
| QRH | Does my frequency vary? | Your frequency varies. |
| QRI | How is the tone of my transmission? | The tone of your transmission is (1. Good; 2. Variable; 3. Bad) |
| QRJ | How many voice contacts do you want to make? | I want to make ... voice contacts. |
| QRK | What is the readability of my signals (or those of ...)? | The readability of your signals (or those of ...) is ... (1 to 5). |
| QRL | Are you busy? | I am busy. (or I am busy with ... ) Please do not interfere. |
| QRM | Do you have interference? | I have interference. |
| QRN | Are you troubled by static? | I am troubled by static. |
| QRO | Shall I increase power? | Increase power. |
| QRP QRP operation In amateur radio, QRP operation means transmitting at reduced power levels while aiming to maximize one's effective range while doing so. The term QRP derives from the standard Q code used in radio communications, where "QRP" and "QRP?" are used to request, "Reduce power," and ask "Should I reduce... |
Shall I decrease power? | Decrease power. |
| QRQ | Shall I send faster? | Send faster (... wpm) |
| QRS | Shall I send more slowly? | Send more slowly (... wpm) |
| QRT | Shall I stop sending? | Stop sending. |
| QRU | Have you anything for me? | I have nothing for you. |
| QRV | Are you ready? | I am ready. |
| QRW | Shall I inform ... that you are calling him on ... kHz (or MHz)? | Please inform ... that I am calling him on ... kHz (or MHz). |
| QRX | When will you call me again? | I will call you again at ... (hours) on ... kHz (or MHz) |
| QRZ | Who is calling me? | You are being called by ... on ... kHz (or MHz) |
| QSA | What is the strength of my signals (or those of ... )? | The strength of your signals (or those of ...) is ... (1 to 5). |
| QSB | Are my signals fading? | Your signals are fading. |
| QSD | Is my keying defective? | Your keying is defective. |
| QSG | Shall I send ... telegrams (messages) at a time? | Send ... telegrams (messages) at a time. |
| QSK | Can you hear me between your signals? | I can hear you between my signals. |
| QSL QSL QSL is one of the Q codes used in radiocommunication and radio broadcasting. A Q code message can stand for a statement or a question . In this case, QSL? means "do you confirm receipt of my transmission?" while QSL means "I confirm receipt of your transmission". Some also take it to mean "Query... |
Can you acknowledge receipt? | I am acknowledging receipt. |
| QSM | Shall I repeat the last telegram (message) which I sent you, or some previous telegram (message)? | Repeat the last telegram (message) which you sent me (or telegram(s) (message(s)) numbers(s) ...). |
| QSN | Did you hear me (or ... (call sign)) on .. kHz (or MHz)? | I did hear you (or ... (call sign)) on ... kHz (or MHz). |
| QSO | Can you communicate with ... direct or by relay? | I can communicate with ... direct (or by relay through ...). |
| QSP | Will you relay a message to ...? | I will relay a message to ... . |
| QSR | Do you want me to repeat my call? | Please repeat your call; I did not hear you. |
| QSS | What working frequency will you use? | I will use the working frequency ... kHz (or MHz). |
| QST | - | Here is a broadcast message to all amateurs. |
| QSU | Shall I send or reply on this frequency (or on ... kHz (or MHz))? | Send or reply on this frequency (or on ... kHz (or MHz)). |
| QSW | Will you send on this frequency (or on ... kHz (or MHz))? | I am going to send on this frequency (or on ... kHz (or MHz)). |
| QSX | Will you listen to ... (call sign(s) on ... kHz (or MHz))? | I am listening to ... (call sign(s) on ... kHz (or MHz)) |
| QSY | Shall I change to transmission on another frequency? | Change to transmission on another frequency (or on ... kHz (or MHz)). |
| QSZ | Shall I send each word or group more than once? | Send each word or group twice (or ... times). |
| QTA | Shall I cancel telegram (message) No. ... as if it had not been sent? | Cancel telegram (message) No. ... as if it had not been sent. |
| QTC | How many telegrams (messages) have you to send? | I have ... telegrams (messages) for you (or for ...). |
| QTH | What is your position in latitude and longitude (or according to any other indication)? | My position is ... latitude...longitude |
| QTR | What is the correct time? | The correct time is ... hours |
| QTU | At what times are you operating? | I am operating from ... to ... hours. |
| QTX | Will you keep your station open for further communication with me until further notice (or until ... hours)? | I will keep my station open for further communication with you until further notice (or until ... hours). |
| QUA | Have you news of ... (call sign)? | Here is news of ... (call sign). |
| QUC | What is the number (or other indication) of the last message you received from me (or from ... (call sign))? | The number (or other indication) of the last message I received from you (or from ... (call sign)) is ... |
| QUD | Have you received the urgency signal sent by ... (call sign of mobile station)? | I have received the urgency signal sent by ... (call sign of mobile station) at ... hours. |
| QUE | Can you speak in ... (language), - with interpreter if necessary; if so, on what frequencies? | I can speak in ... (language) on ... kHz (or MHz). |
| QUF | Have you received the distress signal sent by ... (call sign of mobile station)? | I have received the distress signal sent by ... (call sign of mobile station) at ... hours. |
Some of the common usages vary somewhat from their formal, official sense. QRL? is the accepted form of the question, "Is this frequency in use (or busy)?", the reply to which is typically the letters "C" (dah di dah dit
Morse code
Morse code is a method of transmitting textual information as a series of on-off tones, lights, or clicks that can be directly understood by a skilled listener or observer without special equipment...
), "R" (di dah dit
Morse code
Morse code is a method of transmitting textual information as a series of on-off tones, lights, or clicks that can be directly understood by a skilled listener or observer without special equipment...
) or "Y" (dah di dah dah
Morse code
Morse code is a method of transmitting textual information as a series of on-off tones, lights, or clicks that can be directly understood by a skilled listener or observer without special equipment...
) which, in the Amateur radio tradition, are the Morse code shorthand for "Confirm", "Roger" or "Yes." There are also a few unofficial and humorous codes in use, such as QLF ("try sending with your LEFT foot") and QSC ("send cigarettes", not the official meaning of "this is a cargo vessel"). In the question form, QNB?, is supposed to mean "How many buttons does your radio have?" A reply of the form QNB 45/15 means "45, and I know what 15 of them do." QSJ is sometimes used to refer to the cost of something - "I would like an FT9000 but it is too much QSJ". (QSJ actually means "What is the charge to be collected to ... including your internal charge?").
QSK - "I can hear you during my transmission" - refers to a particular mode of Morse code operating in which the receiver is quickly enabled during the spaces between the dits and dahs, which allows another operator to interrupt transmissions. Many modern transceivers incorporate this function, sometimes referred to as full break-in as against semi-break-in in which there is a short delay before the transceiver goes to receive.
A conversation or contact via amateur radio is often referred to as a QSO, while QSL
QSL
QSL is one of the Q codes used in radiocommunication and radio broadcasting. A Q code message can stand for a statement or a question . In this case, QSL? means "do you confirm receipt of my transmission?" while QSL means "I confirm receipt of your transmission". Some also take it to mean "Query...
cards are collected by both radioamateurs and shortwave
Shortwave
Shortwave radio refers to the upper MF and all of the HF portion of the radio spectrum, between 1,800–30,000 kHz. Shortwave radio received its name because the wavelengths in this band are shorter than 200 m which marked the original upper limit of the medium frequency band first used...
listeners as confirmation of having received the signal of a particular station.
Regarding the speed of the Morse code being sent, if the speed is too fast and the receiving operator cannot copy the code at said speed, that operator may send "QRS", the request to "please slow down." A courteous sender will slow down to match the speed of the slower operator.
QTHR - "at the registered address for my callsign", this is used mainly in the United Kingdom and former colonies. Since business may not be discussed on amateur radio, a ham who has personal equipment to sell might say something like "I have a spare Morse key old chap, please contact me QTHR".
Note: The ARRL codes QNA-QNZ overlap with International Civil Aviation Organization (ICAO) codes but have different meanings.
Aviation
Although the majority of the Q codes have slipped out of common use, several remain part of the standard ICAO radiotelephony phraseology in aviation.| Code | Meaning | Sample use |
|---|---|---|
| QFE | Atmospheric pressure at sea level, corrected for temperature and adjusted to a specified datum such as airfield elevation, when set on the altimeter it reads height | Runway in use 22 Left, QFE 990 millibars |
| QFF Qff QFF is a Q code. It is the MSL pressure derived from the barometric pressure at the station location by calculating the weight of an imaginary air column, extending from the location to sea level, assuming the temperature and relative humidity at the location are the long term monthly mean, the... |
Barometric pressure at a place, reduced to MSL using the actual temperature at the time of observation as the mean temperature | |
| QNE | Atmospheric pressure at sea level in the International Standard Atmosphere (ISA International Standard Atmosphere The International Standard Atmosphere is an atmospheric model of how the pressure, temperature, density, and viscosity of the Earth's atmosphere change over a wide range of altitudes. It has been established to provide a common reference for temperature and pressure and consists of tables of... ), equal to 1013.25 mbar or hPa and used as reference for measuring the pressure altitude Pressure altitude In aviation, pressure altitude is the indicated altitude when an altimeter is set to an agreed baseline pressure setting. The baseline pressure is 1013.25 hPa, equivalent to 1013.25 millibar, or 29.92 inches of mercury. This setting is equivalent to the air pressure at mean sea level in the... |
|
| QNH QNH QNH is one of the many Q codes. It is defined as, "barometric pressure adjusted to sea level." It is a pressure setting used by pilots, air traffic control , and low frequency weather beacons to refer to the barometric setting which, when set on an aircraft's altimeter, will cause the altimeter to... |
Atmospheric pressure at mean sea level (may be either a local, measured pressure or a regional forecast pressure (RPS)). When set the altimeter reads altitude | Request Leeds QNH |
| Code | Meaning | Sample use |
|---|---|---|
| QDM | Magnetic heading to a station | (callsign) request QDM (callsign) |
| QDR | Magnetic bearing from a station | (callsign) request QDR (callsign) |
| QFU | Magnetic bearing of the runway in use | Runway 22 in use, QFU 220 |
| QTE | True bearing from a station | True bearing, True bearing, (callsign) request QTE (callsign) |
| QUJ | True bearing to a station |
| Code | Meaning | Sample use |
|---|---|---|
| QGH | controller-interpreted DF let-down procedure, on UHF or VHF |
Maritime
Q signals are no longer used in the maritime service, as Morse code is now very rarely used.Royal Air Force: QGH signified "Controlled Descent through Clouds"
See also
- ACP-131ACP-131ACP-131 is the controlling publication for the listing of Q codes and Z codes. It is published by NATO Allied countries, and revised from time to time...
- Ten-codeTen-codeTen-codes, also known as ten signals, are code words used to represent common phrases in voice communication, particularly by law enforcement and in Citizens' Band radio transmissions....
- Prosigns for Morse codeProsigns for Morse CodeIn Morse code, prosigns or procedural signals are dot/dash sequences that have a special meaning in a transmission: they are a form of control character...
- International Code of SignalsInternational Code of SignalsThe International Code of Signals is an international system of signals and codes for use by vessels to communicate important messages regarding safety of navigation and related matters. Signals can be sent by flaghoist, signal lamp , flag semaphore, radiotelegraphy, and radiotelephony...
- International maritime signal flagsInternational maritime signal flagsThe system of international maritime signal flags is one system of flag signals representing individual letters of the alphabet in signals to or from ships...
External links
- Handbook for Wireless Telegraph Operators, October, 1909.
- Radio Laws and Regulations of the United States: Edition July 27, 1914. (Includes the 1912 London Radiotelegraphic Convention)
- List of Q codes
- A resource for Morse Code operation in the amateur radio hobby