Traditionally, airline teletype technology uses teleprinters, which are essentially electro-mechanical typewriters that can communicate type messages from point to point through simple electric communications channels, often just pairs of wires. The most modern form of these devices are fully electronic and use a screen, instead of a printer. Teletype machines in World War II A teleprinter (teletypewriter, teletype or TTY) is a now largely obsolete electro-mechanical typewriter which can be used to communicate typed messages from point to point through a simple electrical communications channel, often just a pair of wires. ... A Communications channel (or channel for short), models the medium through which information is transmitted from a sender (or transmitter) to a receiver. ...

Historical development

The airline industry has been making use of teletype technology since the early 1920s using radios stations located at 10 airfields in the United States. The US Post Office and other US govenrment agencies used these radio stations for tranmitting telegraph messages. It was during this time period that the first federal teletype system was introduced in the United States to allow weather and flight information to be exchanged between air traffic facilities. The 1920s was a decade sometimes referred to as the Jazz Age or the Roaring Twenties, usually applied to America. ...

In 1929, Aeronautical Radio Incorporated (ARINC) was formed to manage radio frequencies and licence allocation in the United States, as well as to support the radio stations that were used by the emerging airlines a role, ARINC still fulfils today. ARINC is a private company owned by many of the world's airlines including; American Airlines, Continental Airlines, British Airways, Air France,and SAS. Other non-airline companies also own a share of ARINC including the Ford Motor Company. Aeronautical Radio, Incorporated (ARINC) is the leading provider of transport communications and systems engineering solutions for five major industries (aviation, airports, defense, government and transportation) since 1929. ... American Airlines and American Eagle aircraft at San Juan American Airlines is the largest airline in the world in terms of total passengers transported and fleet size, and the second-largest airline in the world (behind Air France-KLM) in terms of total operating revenues. ... Continental Airlines (IATA: CO, ICAO: COA, and Callsign: Continental) (NYSE: CAL) is an airline of the United States. ... British Airways (LSE: BAY, NYSE: BAB) is the largest airline of the United Kingdom. ... Air France Boeing 747 Air France (Compagnie Nationale Air France) is a subsidiary of Air France-KLM. Before its merger with KLM, it was the national airline of France, employing 71,654 people (as of January 2005). ... Scandinavian Airlines System is a multi-national airline for Norway, Denmark and Sweden, and the leading carrier in the Nordic countries. ... Ford Motor Company is one of the largest automobile manufacturers in the world. ...

In 1949, the Société Internationale de Télécommunication Aeronautique (SITA) was formed as a cooperative by 11 airlines: Air France, KLM, Sabena, Swissair, TWA, British European Airways, British Overseas Airways Corporation, British South American Airways, Swedish A. G. Aerotransport, Danish Det Danske Luftfartselskab A/S, and Norwegian Det Norske Luftfartselskap. Their aim was to enable airlines to be able to use the existing communications facilities in the most efficient and cost-effective manner. Air France Boeing 747 Air France (Compagnie Nationale Air France) is a subsidiary of Air France-KLM. Before its merger with KLM, it was the national airline of France, employing 71,654 people (as of January 2005). ... KLM (in full: Koninklijke Luchtvaart Maatschappij, literally Royal Aviation Company; usual English: Royal Dutch Airlines) is a subsidiary of Air France-KLM. Before its (agreed) take-over by Air France, KLM was the national airline of the Netherlands. ... SABENA was the former national airline of Belgium, which mainly operated from Brussels National Airport and has now been replaced by SN Brussels Airlines. ... Swissair MD-11 Swissair, short for Swiss Air Transport Company Limited, was Switzerlands national airline for 71 years (1931–2002), established when the airlines Belair and Ad Astra Aero (To the Stars) merged. ... The Twa are a pygmy people, of short stature, who were the oldest recorded inhabitants of anthe Great Lakes region of central Africa that now comprises the nations of Rwanda, Burundi, and the Democratic Republic of Congo. ... For alternate usages of BEA see Bea (disambiguation). ... The British Overseas Airways Corporation (BOAC) was the exclusive British state airline from 1939 until 1946 and the long-haul British state airline from 1946. ... British South American Airways (BSAA) was a British state-run airline of the 1940s. ...

Morse code was the general means of relaying information between air communications stations prior to World War II. Generally, it was only necessary to relay a message between one or two stations. After World War II, there was an increase in the number of commercial aircraft operating, and these aircraft were capable of flying greater distances than in the past. As a result, the Aeronautical Fixed Telecommunications Network (AFTN) was implemented worldwide as a means of relaying the necessary air traffic communications, sometimes through the use of radioteletype. 1922 Chart of the Morse Code Letters and Numerals Morse code is a method for transmitting information, using standardized sequences of short and long marks or pulses — commonly known as dots and dashes — for the letters, numerals, punctuation and special characters of a message. ... This article is becoming very long. ... AFTN (Aeronautical Fixed Telecommunication Network) 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. ... This article does not cite its references or sources. ...

Today, the airline industry continues to use teletype messages over ARINC, SITA or AFTN networks as a medium for communicating via messages. Most teletype messages are machine-generated by automatic processes. IATA standardise teletype message formats throughout the airline industry. IATA logo The International Air Transport Association is an international trade organization of airlines headquarted in Montreal, Quebec, Canada. ...

An example of a TTY message (IATA TypeB format)

 QD AAAABBB. - IATA message to AAAABBB (priority=deferred) XXXXYYY 111301 - from (origin code + timestamp) ASM - IATA type (keyword). Identifies type of message UTC - Time mode (Coordinated Universal Time). UTC or LOCAL 27SEP03899E001/TSTF DL Y - Message Reference line NEW - ASM subtype (Action Identifier) BA667/13APRJ 319 C1M25VVA4C26 - Flight and date of flight; fleet & equipment information LHR1340 BCN1610 - Station/time for depart & arrival LHRQQQ 99/1 - Route information. 99 is the passenger departure terminal code QQQBCN 98/A - Route information. 98 is the passenger arrival terminal code QQQQQQ 906/PAYDIV B - Route information. LHRQQQ 999/1 - Route information. 999 is the aircraft arrival terminal code QQQBCN 998/A - Route information. 998 is the aircraft departure terminal code SI - Other supplementary information (free text) 

IATA Teletype messages mostly have a 7 character address whereas an AFTN Teletype message always has an 8-character address. It has been suggested that leap second be merged into this article or section. ... The abbreviation ASM can mean several things: Abstract State Machines, based on the concept of an abstract state machine in computer science Abnormal Situation Management® in Automation (More specifically, industrial or process automation) Academy of Sciences of Moldova Active Shape Model, deformable contour model used by Computer Vision Air-to...