An electronic communication system is a collection of communication networks, tributary stations, relay stations, transmission systems and data terminal equipment. These components are technologically compatible, respond to controls, use common procedures and operate in union. Electric communication systems are of different types, depending on the transmission media, such as optical communication system, power line communication system and radio communication system. Other classifications of communication systems, such as duplex communication system, tactical communications system, emergency communication system, etc. may be based on the technology used or the area of application. This book includes some of the vital pieces of work being conducted across the world, on various topics related to electronic communication systems. It attempts to understand the diverse aspects of electronic communication systems and how these have practical applications. This book is a complete source of knowledge on the present status of this important field.