短語詞組短語synchronous digital transmission technologies 同步數(shù)字傳輸技術Synchronous Digital Transmission Network 同步數(shù)字傳輸網(wǎng)optical synchronous digital transmission network 光同步數(shù)字傳輸網(wǎng)SDN Synchronous Digital Transmission Network 同步數(shù)字傳輸網(wǎng)絡 返回 synchronous digital transmission