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The STM-1 (Synchronous Transport Module level-1) is the SDH ITU-T fiber optic network transmission standard. It has a bit rate of 155.52 Mbit/s. Higher levels go up by a factor of 4 at a time: the other currently supported levels are STM-4, STM-16, STM-64 and STM-256. Beyond this we have wavelength-division multiplexing (WDM) commonly used in submarine cabling.〔(Chapter 8 ) Voice & data communications handbook By Regis J. Bates, Donald W. Gregory〕〔(Table 2 Basic SONET Levels ) The Internet encyclopedia, Volume 1 By Hossein Bidgoli 〕 ==Frame structure== The STM-1 frame is the basic transmission format for SDH (Synchronous Digital Hierarchy). A STM-1 frame has a byte-oriented structure with 9 rows and 270 columns of bytes, for a total of 2,430 bytes (9 rows * 270 columns = 2430 bytes). Each byte corresponds to a 64kbit/s channel.〔(3.3 Basic principles of SDH ) Networks: internet, telephony, multimedia : convergences and complementarities By Daniel Hardy, Guy Malléus, Jean-Noël Méreur〕 TOH: Transport Overhead ( + + ) * : Multiplex Section Overhead * : Regeneration Section Overhead * : AU-4 Pointers VC4: Virtual Container-4 payload ( + ) * : Path Overhead 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「STM-1」の詳細全文を読む スポンサード リンク
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