For the 1959 – present phonetics, the underlined syllable of each letter word should be emphasized, and each syllable of the code words for the figures (1969 – present) should be equally emphasized.  Several of the pronunciations indicated are slightly modified from their normal English pronunciations: [ˈælfa, ˈbraːˈvo, ˈdeltɑ, ɡʌlf, ˈliːmɑ, ˈɔskɑ, siˈerɑ, ˈtænɡo, ˈuːnifɔrm, ˈviktɑ, ˈjænki], partially due to the substitution of final schwas with the [ɑ] vowel. Radio call signs used for communication in manned spaceflight are not formalized or regulated to the same degree as for aircraft. An early version of the phonetic alphabet appears in the 1913 edition of The Navy Bluejackets’ Manual. Hence, in the hypothetical Djibouti call sign, J29DBA, the prefix is J2, the number is 9, and the suffix is DBA.
Each transmission of figures is preceded and followed by "as a number" spoken twice.
Britain has no call signs in the American sense, but allows broadcast stations to choose their own trade mark call sign up to six words in length.
These were not globally unique, so a one-letter company identifier (for instance, 'M' and two letters as a Marconi station) was later added. Maritime coast stations on high frequency (both radiotelegraphy and radiotelephony) were assigned three letter call signs. VE1AB, VA3ABC, VO1ZZ or VY2ZZZ. The phonetic alphabet, or "spelling alphabet", replaces letters and numbers with code words. In addition to the traditional military usage, civilian industry uses the alphabet to avoid similar problems in the transmission of messages by telephone systems. The International Radiotelephony Spelling Alphabet (IRSA) is its proper name, and it was created by the International Civil Aviation Organization (ICAO) to help decipher similar sounding letters and numbers between different countries and organizations. Broadcasters are allocated call signs in many countries. Originally, both ships and broadcast stations were assigned call signs in this series consisting of three or four letters. The United States Army uses fixed station call signs which begin with W, such as WAR, used by U.S. Army Headquarters.  Because the ITU governs all international radio communications, it was also adopted by most radio operators, whether military, civilian, or amateur. The only continuity in call signs for spacecraft have been the issuance of "ISS"-suffixed call signs by various countries in the amateur radio service as a citizen of their country has been assigned there.
A call sign can be formally assigned by a government agency, informally adopted by individuals or organizations, or even cryptographically encoded to disguise a station's identity. It was defined in one or more of CCBP-1: Combined Amphibious Communications Instructions, CCBP3: Combined Radiotelephone (R/T) Procedure, and CCBP-7: Combined Communication Instructions. Have good radio transmission and readability characteristics.
The late King Hussein of Jordan was issued a special amateur license number, JY1, which would have been the shortest possible call sign issued by the Hashemite Kingdom of Jordan. The International Radiotelephony Spelling Alphabet, commonly known as the NATO phonetic alphabet or the ICAO phonetic alphabet, is the most widely used radiotelephone spelling alphabet. Aircraft registration numbers internationally follow the pattern of a country prefix, followed by a unique identifier made up of letters and numbers. For the UK company, see, Unique designation for a transmitting station, Learn how and when to remove this template message, International Civil Aviation Organization, Australian Communications and Media Authority, "CALL SIGNS/LETTERS - The Museum of Broadcast Communications", "FCC: Wireless Services: Ship Radio Stations: Licensing", United States Call Sign Policies (Early History), United States (FCC) Call Sign Reservation and Authorization System, Internet Radio Uniform Callsign (IRUC) program, Fictional Story About Military Call Signs, Broadcasting undertaking callsigns possibly available for assignment, https://en.wikipedia.org/w/index.php?title=Call_sign&oldid=987302733, Articles needing additional references from March 2013, All articles needing additional references, Creative Commons Attribution-ShareAlike License. Defined by various international conventions on radio, including: For the 1938 and 1947 phonetics, each transmission of figures is preceded and followed by the words "as a number" spoken twice. The call sign might be abbreviated to the final two or three numbers during operations, for example: Coast Guard zero two one. The International Radiotelephony Spelling Alphabet, commonly known as the NATO phonetic alphabet or the ICAO phonetic alphabet, is the most widely used radiotelephone spelling alphabet. Those calls follow the land mobile format of the initial letter K or W followed by 1 or 2 letters followed by 3 or 4 numbers (such as KX0983 or WXX0029). After all of the above study, only the five words representing the letters C, M, N, U, and X were replaced. It was finally adopted by the IMO in 1965. Voluntary ships (mostly pleasure and recreational) are not required to have a radio. ", "Radioman 3 & 2 Training Course Manual NAVPERS 10228-B", "The Evolution and Rationale of the ICAO (International Civil Aviation Organization) Word-Spelling Alphabet, July 1959", "Alpha, Bravo, Charlie: how was Nato's phonetic alphabet chosen? The use of call signs as unique identifiers dates to the landline railroad telegraph system.
Pronunciation was not defined prior to 1959. For example, it is often used in the retail industry where customer or site details are spoken by telephone (to authorize a credit agreement or confirm stock codes), although ad-hoc coding is often used in that instance. , The pronunciation of the digits 3, 4, 5, and 9 differs from standard English – being pronounced tree, fower, fife, and niner.
Aside from the standardized prefix, the station operator may select a 2-, 3- or 4-letter suffix to the callsign …
The CCB alphabet itself was based on the U.S. Joint Army/Navy spelling alphabet. As seen in the picture, all flags represent the phonetic alphabet and have meanings different than the above chart.
In the United States, the first letter generally is K for stations located west of the Mississippi River and W for eastern stations. Some published versions incorrectly list "alpha" and "juliet" – presumably because of the use of spell checker software – but those spellings are never correct and should be changed back to "alfa" and "juliett" wherever such mistakes are found.. For example, an aircraft registered as N978CP conducting a general aviation flight would use the call sign November-niner-seven-eight-Charlie-Papa.