Transmission and multiplexing . optical interfaces for equipment and systems relating to the synchronous digital hierarchy uit - t recommandation g . 957 modified 传输和多路通信.同步数字体系设备和系统用光学接口
Optical relay network technoiogy is to buiidup various teiephone networks by the flexible sdh transmission equipment working with stored program control switches . at present , it has been adopted by most of telecom operators in iocal networks of pstn and becomes an eff6ctive solution to imp the operation cost , improve the qos , as well as faciiitat6 the oam 光中继组网就是利用同步数字体系( sdh )传输设备本身组网的灵活性来配合程控交换机组成各种电话网络，在目前的公共电话交换网络( pstn )中的本地网络中，较多地被电信运营商所采用。
Fully considering the system ' s reliabilty , being real - time , speed and extensibility , it finally chooses the sdh as the system network of cors through deep compration and alalysis of four special data lines supplied by china telecom , so that an effective interconnection among the stations and the workstations in the control - center comes true 摘要充分考虑系统可靠性、实时性、通信速率、可扩充性等因素，通过对中国电信提供的4种数据专线服务的综合分析比较，选择了同步数字体系作为系统通信网络，实现了控制中心各工作站和各基准站之间的高速互联。
