Time Division Circuit Switching

Abstract

The previous chapters have addressed general topics related to digital switching, such as general switching networks and their controls, switching definitions, traffic theory, and switching system control and software. Many of these concepts are independent of whether the switch is analog or digital, space or time, or circuit- or packed-oriented. As the topics were discussed, areas of uniqueness were highlighted for the various types of networks. This chapter introduces the concept of time division circuit-switching networks and indicates how a circuit-switching function is performed in a time division system. The time division circuit-switching function is illustrated first for analog time division systems and then for digital time division systems, which forms the basics for digital switching. The digital time division networks then become the basis for the digital-switching systems discussed in Chapter 9. The remainder of this chapter describes the techniques and components associated with the networks characterized as time division circuit switches, as distinct from the packet switches described in Chapter 6. This chapter concludes with a discussion of potential future technologies for time division circuit switches, including sub-and super-rate, and optical switching. Later chapters will discuss the analog and digital terminations for the switch fabric, the impact of ISDN on the network, and some of the switching system architectures developed for public and private switching systems.