Like all digital transmission systems, digital subscriber loop carrier seems destined to play an ever-increasing role in modern communication networks. This trend derives its strength from basic and pervasive factors: (1) the great ease with which digital transmission can support new services, particularly those related to any form of data transmission; (2) the seemingly inexhaustible potential of digital integrated circuit technology to realize ever-decreasing cost, size, and power-per-circuit function; (3) the great promise digital transmission holds for synergy with digital switching. This paper provides an overview to a series of papers that describe in detail AT&T Technologies eminently successful entry in this market, the SLC® 96 Subscriber Loop Carrier System. Emphasis is placed on the background leading to the development and the forces that shaped the system's architecture.