DDF and ODF in communication network, what is SDH?
First, DDF (digital patch panel) is between the digital multiplexing equipment, digital multiplexing equipment and program-controlled exchange equipment or data services and other professional equipment between the wiring connection equipment. Digital distribution frame, also known as high-frequency patch panel, in the digital communication more and more advantages, it can make digital communication equipment, the connection of digital streams into a whole, from the rate of 2Mb / s ~ 155Mb / s signal input , The output can be terminated in the DDF shelf, which for the wiring, transfer line, transfer, expansion have brought great flexibility and convenience. Second, ODF (OpticalDistributionFrame, fiber patch panel), for optical fiber communication system in the central trunk cable into the end and distribution, can easily achieve the fiber line connection, distribution and scheduling. Third, SDH (Synchronous Digital System), according to the ITU-T proposed definition, is the transmission of digital signals of different speeds to provide the corresponding level of information structure, including multiplexing methods and mapping methods, and the associated synchronization method composed of a Technical system.
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