A software reliability engineering success story. AT&T's Definity PBX

Over the past five years, a number of quality improvement initiatives have been completed on AT&T's Definity PBX product development process. This paper describes the quality improvement initiatives and the quality improvement results that were achieved. The new initiatives include incremental development and operational-profile, statistical testing. The quality improvement results include an increase in customer satisfaction with product quality and a decrease in development and testing costs and intervals.