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已建设和拟建设的管道专用通信网,因其容量小(均为34Mbit/s)且主要用于电话业务,已不适应计算机网络通信、电视会议、多媒体信息传输等业务开展的需要,扩大新的通信干线容量势在必行。邮电部、中国联合通信总公司均采用了同步数定等级(SDH)制,以取代准同步数字等级(PDH)制,扩大其通信系统容量,面向全国开放。而石油专用网也具备了向同步数字等级(SDH)制过渡的条件,建议再建长途通信干线时,其容量还要扩大,应不低于155Mbit/s。
Owing to their small capacity (both 34 Mbit / s) and mainly used for telephone service, the dedicated pipeline communication network which has been constructed and to be constructed has not been adapted to the needs of such business as computer network communication, video conference and multimedia information transmission, etc., The communication trunk capacity is imperative. The Ministry of Posts and Telecommunications and China United Telecommunications Corporation adopted the SDH system in place of the PDH system to expand the capacity of their communication systems and open up to the whole country. The oil private network also has the transition to the synchronous digital hierarchy (SDH) conditions, the proposed reconstruction of long-distance communications trunk, its capacity should also be expanded, should not be less than 155Mbit / s.