In pursuing its vision that digital signals will come to dominate not only voice communications but also various services on an integrated basis in future telecommunications, NTT has successfully completed a major part of telephone network preparations by digitizing all of its networks by the end of 1997. Accompanying digitization, it has also started providing various new services including the initiation of best-effort services through OCN. At the same time, the steady progress in Internet diffusion, the globalization of enterprise networks and inter-company electronic transactions are leading to the full scale usage of IP network communications. Because IP networks are still faced with pressing demand and unresolved issues, NTT believes it is also necessary to structure and provide computer-compatible networks suitable for IP communications by shifting from telephone-focused architecture in order to respond better to these growing needs. This paper overviews the digital network assets including ISDN that NTT has accumulated as a carrier as well as the IP networks such as the Internet that have spread throughout our societies. It also outlines new access services and network offerings based on optical and other technologies and the ATM networks that serve as the infrastructure for highly reliable and economical IP networks, and presents our thinking behind how such networks will be organically combined.