Introduction

Abstract

This text is concerned with the way computer-based information is transferred over long distances, and with the organisation of the communication system to meet various needs. A computer system usually consists of a CPU, memory, peripherals (on site) and communication devices. These are normally connected together by one or more short, high speed, data highways (figure 1.1). Computer organisation around the data highway is one of the topics of computer architecture. This book assumes the reader has some knowledge of computer system organisation and is familiar with using a computer. The subject of computer communications involves the problems and solutions of transporting data over distances longer than the internal computer data highway. For practical purposes we will treat a communications device as a piece of equipment that is used to transfer computer data to other equipment outside the computer room.