Abstract: “As we know that GSM coder is used for mobile communication and G.729 is commonly used in internet communication eg.VOIP. For modern communication network it is important that both networks should use interoperability. In this paper we discuss the transcoding system which convert speech codec format between G.729 and GSM. Transcoding system which we required for connecting two different networks, it should required less computation than the conventional decode thenencode (DTE). Through this transcoding system speech codec format can easily exchange information between these two different networks”

Keywords: G.729, GSM, Transcoding System