Chapter 9 Communications Circuits 9.1 INTRODUCTION 9.2 COMMUNICATIONS CIRCUITS The physical connection between two or more points used for the purpose of communicating is called a line or circuit A link is a segment of a circuit between two points a node is a functional unit that connects two transmission links or lines www.gxmu.edu.cnChapter 9 Communications Circuits 9.1 INTRODUCTION 9.2 COMMUNICATIONS CIRCUITS The physical connection between two or more points used for the purpose of communicating is called a line or circuit. A link is a segment of a circuit between two points. A node is a functional unit that connects two transmission links or lines. www.gxmu.edu.cn