The (International) 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.
The Aeronautical Fixed Telecommunications Network (AFTN) is a worldwide system of aeronautical fixed circuits provided, as part of the Aeronautical Fixed Service, for the exchange of messages and/or digital data between aeronautical fixed stations having the same or compatible communications characteristics. AFTN comprises aviation entities including: ANS providers, aviation service providers, airport authorities and government agencies, to name a few. It exchanges vital information for aircraft operations such as distress messages, urgency messages, flight safety messages, meteorological messages, flight regularity messages and aeronautical administrative messages.
As defined by FS-1037C and ITU Radio Regulations, radiodetermination is:
"the determination of the position, velocity or other characteristics of an object, or the obtaining of information relating to these parameters, by means of the propagation properties of radio waves."
Fixed-satellite service is – according to article 1.21 of the International Telecommunication Union's (ITU) Radio Regulations (RR) – defined as A radiocommunication service between earth stations at given positions, when one or more satellites are used; the given position may be a specified fixed point or any fixed point within specified areas; in some cases this service includes satellite-to-satellite links, which may also be operated in the inter-satellite service; the fixed-satellite service may also include feeder links for other space radiocommunication services.
Air Traffic Services Message Handling Services (AMHS) is a standard for aeronautical ground-ground communications based on X.400 profiles. It has been defined by the ICAO.
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.
Radio communication service or radiocommunication service is according to Article 1.19 of the International Telecommunication Union's Radio Regulations, defined as "a service…involving the transmission, emission and/or reception of radio waves for specific telecommunication purposes".
Mobile service is – in line to ITU Radio Regulations – a radiocommunication service between mobile and land stations, or between mobile stations (CV).
In telecommunications, a fixed service is a radiocommunication service between specified fixed points.
Inter-satellite service is – according to Article 1.22 of the International Telecommunication Union's (ITU) Radio Regulations (RR) – defined as «A radiocommunication service providing links between artificial satellites.
Safety service is – according to Article 1.59 of the International Telecommunication Union's (ITU) Radio Regulations (RR) – defined as «A radiocommunication service used permanently or temporarily for the safeguarding of human life and property.»
A feeder link is – according to Article 1.115 of the International Telecommunication Union´s (ITU) ITU Radio Regulations (RR) – defined as:
A radio link from an earth station at a given location to a space station, or vice versa, conveying information for a space radiocommunication service other than for the fixed-satellite service. The given location may be at a specified fixed point, or at any fixed point within specified areas.
Aeronautical mobile service is – according to Article 1.32 of the International Telecommunication Union's (ITU) Radio Regulations (RR) – defined as "A mobile service between aeronautical stations and aircraft stations, or between aircraft stations, in which survival craft stations may participate; emergency position-indicating radiobeacon stations may also participate in this service on designated distress and emergency frequencies."
Aeronautical mobile-satellite service is – according to Article 1.35 of the International Telecommunication Union's (ITU) Radio Regulations (RR) – defined as «A mobile-satellite service in which mobile earth stations are located on board aircraft; survival craft stations and emergency position-indicating radiobeacon stations may also participate in this service. . »
Ship earth station is – according to Article 1.78 of the International Telecommunication Union's (ITU) ITU Radio Regulations (RR) – defined as «A mobile earth station in the maritime mobile-satellite service located on board ship.»
Aeronautical mobile (R) service is – according to Article 1.33 of the International Telecommunication Union's (ITU) Radio Regulations (RR) – defined as "An aeronautical mobile service reserved for communications relating to safety and regularity of flight, primarily along national or international civil air routes."
Aeronautical mobile (OR) service is – according to Article 1.34 of the International Telecommunication Union's (ITU) Radio Regulations (RR) – defined as "An aeronautical mobile service intended for communications, including those relating to flight coordination, primarily outside national or international civil air routes".
Aeronautical mobile-satellite (R)° service is – according to Article 1.36 of the International Telecommunication Union's (ITU) Radio Regulations (RR) – defined as «An aeronautical mobile-satellite service reserved for communications relating to safety and regularity of flights, primarily along national or international civil air routes.»
Aeronautical mobile-satellite (OR)°° service is – according to Article 1.37 of the International Telecommunication Union's (ITU) Radio Regulations (RR) – defined as «An aeronautical mobile-satellite service reserved for communications relating to safety and regularity of flights, primarily outside national or international civil air routes.»
