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In aviation, ACARS (; an acronym for Aircraft Communications Addressing and Reporting System) is a digital datalink system for transmission of short messages between aircraft and ground stations via airband radio or satellite. The protocol was designed by ARINC and deployed in 1978, using the Telex format. More ACARS radio stations were added subsequently by SITA. ==History of ACARS== Prior to the introduction of datalink in aviation, all communication between the aircraft and ground personnel was performed by the flight crew using voice communication, using either VHF or HF voice radios. In many cases, the voice-relayed information involved dedicated radio operators and digital messages sent to an airline teletype system or successor systems. Particularly, the airlines paid the flight and cabin crews according to whether the aircraft was Out of the gate, Off the ground, On the ground, or In the gate. The flight crews reported these times by voice to geographically dispersed radio operators. Anecdotally, the airlines believed the flight crews "fudged" these reported times to the crews benefit, so believed they would save not only the cost of the radio operators, but also would realize a labor savings for the flight and cabin crews through more accurate time reporting. In an effort to reduce crew workload and improve data integrity, the engineering department at ARINC introduced the ACARS system in July 1978, as essentially an automated time clock system. Teledyne Controls produced the avionics and the launch customer was Piedmont Airlines. The original expansion of the abbreviation was "Arinc Communications Addressing and Reporting System".〔http://www.arinc.com/downloads/product_collateral/acars_first_datasheet.pdf〕 Later, it was changed to "Aircraft Communications, Addressing and Reporting System". The original avionics standard was ARINC 597, which defined an ACARS Management Unit (MU) consisting of discrete inputs for the doors, parking brake and weight on wheels sensors to automatically determine the OOOI times and generate and send as telex messages. It also contained a Minimum Shift Keying (MSK) modem used to transmit the OOOI reports over the existing VHF voice radios. Global standards for ACARS were prepared by the Airlines Electronic Engineering Committee (AEEC). The first day of ARINC operations saw about 4,000 transactions, but ACARS did not experience widespread use by the major airlines until the 1980s. Early ACARS systems were extended over the years to support aircraft with digital data bus interfaces, flight management systems, and printers. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Aircraft Communications Addressing and Reporting System」の詳細全文を読む スポンサード リンク
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