略語大辞典 [C] 17 SDH synchronous digital hierarchy (standard) 新同期網. 同期式ディジタル階層(通信規格). ディジタル多重光通信方式.synchronous digital hierarchy (standard); issued by CCITT/ETSI; designed for the transmission and multiplexing of digital signals at bit rates up to 2.5 Gbit/s; an equally-radicalsystem for transporting switched si 丸善「略語大辞典」JLogosID : 11859017