Asynchronous mapping of 2.048 Mbit/s tributary into SDH VC-12

SDH has been rapidly acknowledged as a world-wide transmission standard replacing the existing PDH infrastructure mainly because it offers plenty of overhead capacity and cross-connect capabilities required as a basis for efficient networking. The compatibility between SDH and PDH is one major feature of SDH. In public networks, 2.048 Mbit/s is basic transmission interface. Mapping the 2.048 Mbit/s tributary into STM-1 performs an important role in realizing the compatibility between SDH and PDH. There are three ways to mapping 2.048 Mbit/s tributary into VC-12: asynchronous mapping, bit synchronous mapping and byte synchronous mapping. Asynchronous mapping is needed at the interface between the PDH 2.048 Mbit/s and SDH equipment. An overview is given of asynchronous mapping of 2.048 Mbit/s tributary into SDH VC-12 and the theory of positive/zero/negative justification and the relative parameter is discussed. The major function blocks are also shown. The whole process of mapping can be implemented with CMOS technology