ASBU 501 - A Digital SPC Voice/Data Switching System

The ASBU 501 is a fourth-generation all-digital switch employing distributed control architecture and a functional top-down design. This paper is organized in three major sections describing the structured system design, the basic equipment, and the software design principles for distributed control. The first section diagrams the layered functional structure and describes the subsystems, function blocks, and unit level (hardware and software). The second section on distributed digital equipment gives a description of the components for both telephony and data switching. The basic switching units which house and distribute the hardware devices are explained and a description and function of all of the equipment is provided. The third section discusses the software design principles utilized in the ASBU 501 distributed control system.