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Radioteletype (RTTY) is a telecommunications system consisting originally of two or more electromechanical teleprinters in different locations connected by radio rather than a wired link. These machines were later superseded by personal computers (PCs) running software to emulate teleprinters. Radioteletype evolved from earlier landline teleprinter operations that began in the mid-1800s. The US Navy Department successfully tested printing telegraphy between an airplane and ground radio station in 1922. Later that year, the Radio Corporation of America successfully tested printing telegraphy via their Chatham, Massachusetts, radio station to the R.M.S. Majestic. Commercial RTTY systems were in active service between San Francisco and Honolulu as early as April 1932 and between San Francisco and New York City by 1934. The US military used radioteletype in the 1930s and expanded this usage during World War II. From the 1980s, teleprinters were replaced by computers running teleprinter emulation software. The term radioteletype is used to describe both the original radioteletype system, sometimes described as "Baudot", as well as the entire family of systems connecting two or more teleprinters or PCs using software to emulate teleprinters, over radio, regardless of alphabet, link system or modulation. In some applications, notably military and government, radioteletype is known by the acronym RATT (Radio Automatic Teletype).〔(【引用サイトリンク】title=MOD Acronyms and Abbreviations )〕 ==History== Landline teleprinter operations began in 1849 when a circuit was put in service between Philadelphia and New York City.〔RTTY Journal Vol. 25 No. 9, October 1977: 2.〕 Émile Baudot designed a system using a five unit code in 1874 that is still in use today. Teleprinter system design was gradually improved until, at the beginning of World War II, it represented the principal distribution method used by the news services. Radioteletype evolved from these earlier landline teleprinter operations. The US Department of the Navy successfully tested printing telegraphy between an airplane and ground radio station in August 1922.〔("Typing in Airplane Received by Radio” ), ''The New York Times'', August 10, 1922, accessed August 25, 2011.〕〔(【引用サイトリンク】title=U.S. Patent No. 1,485,212 )〕〔(【引用サイトリンク】title=Teletype radio plane set, used by Navy Dept., to receive typewritten radio messages from Naval airplanes )〕 Later that year, the Radio Corporation of America successfully tested printing telegraphy via their Chatham, MA radio station to the R.M.S. Majestic.〔("Radio Now As Fast As Wire Messages” ), ''The New York Times'', November 14, 1922, accessed November 4, 2010.〕 An early implementation of the Radioteletype was the Watsongraph,〔(SYSTEM OF COMMUNICATION; Patent number: 1847030 )〕 named after Detroit inventor Glenn Watson in March 1931. Commercial RTTY systems were in active service between San Francisco and Honolulu as early as April 1932〔"Teletype Now Used on Radio Circuits to Hawaii by R.C.A. Communications, Inc., for All Its Messages", Telegraph and Telephone Age, Oct 1, 1932〕 and between San Francisco and New York City by 1934.〔Anderson, Phil W0XI, "The ABC's of RTTY", CQ The Radio Amateur's Journal Vol.40 No. 11, November 1984: 34-35〕 The US Military used radioteletype in the 1930s and expanded this usage during World War II. The Navy called radioteletype ''RATT'' (Radio Automatic Teletype) and the Army Signal Corps called radioteletype ''SCRT'', an abbreviation of Single-Channel Radio Teletype. The military used frequency shift keying technology and this technology proved very reliable even over long distances. From the 1980s, teleprinters were replaced by computers running teleprinter emulation software. 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「Radioteletype」の詳細全文を読む スポンサード リンク
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