ISDN Centrex Opportunities in the Corporate Office.

AT&T, together with Local Exchange Carriers (LECs) and key customers, has been testing the economy and practical utility of ISDN in a series of case studies across a range of industries. This document summarizes the results of one of these "TriVista" studies that was done in co-operation with Southwestern Bell and a large multi-industry corporation. It was prepared by a team consisting of members from AT&T Network Systems Product Management, Account Management, Network Market Planning, Network Market Operations, Document Development, and AT&T Bell Laboratories Systems Engineering. After the study team examined the present voice and data environment, as well as the projected future business and communications requirements, two alternative systems were engineered - one using 5E4(2) ISDN CENTREX service provided by Southwestern Bell, and the other using a PBX and a Local Area Network. An economic analysis revealed that the two approaches provided baseline features (serving the present voice/data mix of users) at roughly the same cost. When the two alternatives were redesigned to accommodate the projected growth in PC usage, the ISDN CENTREX solution had a life cycle cost advantage of 12%. Advances in technology, such as multi-point DSLs, are expected to provide additional savings. Finally, the team identified a number of applications that could be developed to effectively utilize currently available ISDN CENTREX technology to meet business needs and increase end-user productivity. environment, as well as the projected future business and engineered - one using 5E4(2) ISDN CENTREX service provided by