Physical layer standards for DS1 rate access and transport

The authors describe some of the major issues which had to be addressed in physical layer standards for DS1 rate access and transport. They also look at adaptation to the requirements of ISDN (integrated services digital network) primary rate access and provide a preview of a new technology emerging from standards development which offers the promise of significantly reduced access costs for DS1 services. They explain how the introduction of this technology poses its own set of problems, and how this and other issues are being addressed