Book excerpt: This book takes a historical approach that shows students how technologies have built upon each other so they have an appreciation of how and why current technologies exist.Beginning with an overview of the field, this text provides a historical context for information systems, setting the stage chapters that cover signaling, encoding, error-control, connections, and digital communications. Various networking technologies are also introduced to orient the reader to applications such as network security, wireless networks, and how to plan, design, and implement networks.This text is suitable for business professional who want an introduction to the field of information systems or to refresh their knowledge.