Explain difference between SDH and PDH?

SDH is abreviated as Synchronous Digital Hierarchy while PDH is plesiochronous Digital Hieratchy.

Both Technologies is associated with digital Multiplexers

SDH is very useful equipment that is used for the telecommunication sector in easy transfer of data. Earlier PDH was widely used but due to some of its weaknesses, SDH has replaced the use of PDH. But not everywhere. Point to Point applications are still used mainly by PDH, and also, it’s cheaper.

PDH is Plesiochronous Digital Hierarchy and SDH is Synchronous Digital Hierarchy.Both are used in PCM transmission systems. Both use TDM principles for PCM frames.

The difference is In PDH the clock used is not the same throughout the transmission network. But in SDH asynchronous clock is used in the entire Transmission system. PDH is the old system used for only point to point communication and interconnectivity between the sytem is difficult. Whereas SDH is the lattest system used in any kind of transmission configuration and interconnectivity between different systems is very easy. PDH used in2Mb,8Mb,Mb and Mb systems only. But SDH used in STM-1 (.Mbps,STM-4(.Mbps),STM-(2.5Gbps) and STM- (G BPS) transmission systems.

Both PDH and SDH are terminologies associated with digital multiplexers used in exchanges. The different hierarchies having different bit rates are combined. These hierarchies will comprised of many such bit streams/channels (either 24,30 or multiples) often called as tributaries.

SDH is very useful equipment that is used for the telecommunication sector in easy transfer of data. Earlier PDH was widely used but due to some of its weaknesses, SDH has replaced the use of PDH. But not everywhere. Point to Point applications are still used mainly by PDH, and also, it’s cheaper.

PDH or the plesiochronous digital hierarchy is a popular technology that is widely used in the networks of telecommunication in order to transport the huge amounts of data over the digital equipment for transportation like microwave radio or fiber optic systems

PDH & SDH is very useful equipment that is used for the telecommunication sector in easy transfer of data. Earlier PDH was widely used, but due to some of its weaknesses SDH has replaced the use of PDH. But not everywhere. Point to Point applications are still used mainly by PDH, and also, it’s cheaper.

Summary: SDH is very useful equipment that is used for the telecommunication sector in easy transfer of data. Earlier PDH was widely used but due to some of its weaknesses, SDH has replaced the use of PDH. But not everywhere. Point to Point applications are still used mainly by PDH, and also, it’s cheaper.

PDH or the plesiochronous digital hierarchy is a popular technology that is widely used in the networks of telecommunication in order to transport the huge amounts of data over the digital equipment for transportation like microwave radio or fiber optic systems. The term plesiochronous has been derived from the Greek work ‘plesio’ that means ‘near’ and ‘chronos’ meaning time. This means that the PDH works in a state when the various different parts of a network are clearly synchronized. But with the change in technology, the PDH is now being replaced by the SDH or what is popularly called as synchronous digital hierarchy. The SDH is useful equipment that is used in most of the telecommunications networks.

This PDH helps in proper transmission of the data that generally runs at the similar rate but allows some slight variation in the speed than the nominal rate. The basic transfer rate of the data is 2048 kilobits per second. For instance, in each speech transmission, the normal rate breaks into different thirty channels of 64 kilobits per second along with two different 64 kilobits per second in order to perform the tasks of synchronization and signaling. The typical rate of transmitting the data over the fiber optic systems is 565 Mbit/sec in order to transport the data in the long distance. But as the technology has improved with the passing of time, now the telecommunication companies have replaced the PDH equipment with that of the SDH equipment, which has the capability of transmitting the data at much higher rates as compared to the PDH system.

The SDH is an international standard that is highly popular and used for its high speed data transfer of the telecommunication and digital signals. This synchronous system has been specially designed in order to provide a simple and flexible network infrastructure. This system has brought a considerable amount of change in the telecommunication networks that were based on the optical fibers as far as performance and cost were concerned.

The weaknesses that PDH faced paved way for the introduction and use of the SDH systems. Although the PDH proved to be a breakthrough in the field of digital transmission, the weaknesses that made it less demanded.

PDH is Plesiochronous Digital Hierarchy and SDH is Synchronous Digital Hierarchy.Both are used in PCM transmission systems. Both use TDM principles for PCM frames.The difference is In PDH the clock used is not the same throughout the transmission network. But in SDH a synchronous clock is used in the entire Transmission system.PDH is the old system used for only point to point communication and interconnectivity between the sytem is difficult.Whereas SDH is the lattest system used in any kind of transmission configuration and interconnectivity between different systems is very easy.PDH used in 2Mb,8Mb,34Mb and 140 Mb systems only.But SDH used in STM-1(155.52Mbps,STM-4(622.08Mbps),STM-16(2.5Gbps) and STM-64(10G BPS) transmission systems.There are many merits in SDH Easy for Add Drop multiplexing/Demultiplexing is easy.Very useful for Ring configuration in optical communications.Easy growth to high bit rates in steps with evolution of transmission technology.Capable of transporting ATM(Asynchronous Transfer Mode) channels,DLC(Digital Loop Carrier) is working on SDH.SDH is the Indian sytem which is equivalent to American SONET(Synchronous Optical Network)

Thanks for invite but its not my expertise