This reference is the first place to turn for information about all types of data communications systems. Written by noted best-selling author Gil Held, the third edition features new chapters on client/server systems, internetworking, and video conferencing, as well as thorough updates for all other chapters. Communications engineers and technicians designing all types of communications systems will find in-depth coverage of both the conceptual foundation and essential technology, including components, network design and configurations, transmission media, protocols, topologies, architectures, and future technology.