This document discusses computer networking technology. It defines key concepts like communication systems having senders, mediums, and receivers. It describes different modes of data transmission including simplex, half-duplex, and full-duplex. It also discusses different types of communication media such as bounded media like twisted pair cables and unbounded media like wireless transmission. Finally, it outlines common computer network models and categories including client-server networks, peer-to-peer networks, and local area networks.