Telecommunications represents the transmission of signals over distance for the purpose of communication. In modern times, this process typically involves the sending of electromagnetic waves by electronic transmitters. Over the past few decades communications systems have increased in complexity to the point where system design and performance analysis can no longer be conducted without significant level of computer support. Nowadays there are numerous networks that connect communications devices, including computer networks, public telephone networks, radio networks, and television networks. In order to become familiar with new technology trends the readers must understand how complex computer based communications systems function. The aim of this book is to provide students with the fundamental knowledge of networking and data communications techniques.