The major telecommunication equipment suppliers over the world developed SDH products during recent years by converging vast investment and man-power

as ITU-T finalized the fundanental recommendations for SDH system. SDH products

as a new generation

will be widely deployed in the telecommunication networks. The hardware of SDH products is more complex than that of the PDH equipments and the software lines of code is much more than that of the PDH supervisory system. In this paper

from practical point of view

introduced briefly on the hardware

software

networking and synchronization technologies which were adopted in SDH products development.