Airline teletype

From Freepedia

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.

Historical development

The airline industry has been making use of teletype technology since the early 1930s. It was during this time period that the first federal teletype stystem was introduced in the United States to allow weather and flight information to be exchanged between air traffic facilities.

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 Corporation, 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.

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 commerical 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 radio teletype.

Today, the airline industry continues to use teletype messages over 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.

An example of a TTY message

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

SITA Teletype messages often have a 7 character address whereas a AFTN Teletype message always has a 8 character address.

QU HDQRMAA .HDQRM1P 061444 HDQ1P 445577/EC3 1SMITH/JOHNMR AA1234Y 18NOV YYZLGA SS1/14001515 OSI AA CTCT BUNBUN TRAVEL 416 555 8896