Computers In Communication

Computers in Communication Gordon Brebner iii The book “Computers in Communication” by Gordon Brebner was originally published by McGraw-Hill International (UK) Limited in 1997. This edition has been made available in electronic PDF form by the author, following the original version going out of print and the copyright reverting to the author. All identified typographical errors in the original edition have been corrected, but otherwise there has been no updating of the content. In particular, all page numbering is the same as in the original version. c 2002 Gordon Brebner. All rights reserved. You may save a local Copyright copy or print a copy of this book, or parts of this book, for your own personal use, provided that identification of the title and author, and this copyright notice, is not removed. Any commercial exploitation is expressly prohibited. All trademarks are acknowledged. To Rosemary CONTENTS Preface xiii 1 Introduction 1.1 1.2 1.5 1.6 Background Uses of computer communications 1.2.1 Computer-oriented communication 1.2.2 Telecommunications 1.2.3 Radio and television broadcasting 1.2.4 Summary of uses of computer communications Physical links 1.3.1 Physical media and their properties 1.3.2 Physical communication services How computers communicate 1.4.1 Information, time and space 1.4.2 Agreement and implementation 1.4.3 Human influences Chapter summary Exercises and further reading 1 4 4 8 10 11 12 14 20 26 26 27 29 31 32 2 Information 35 2.1 2.2 Introduction Agreement on information types 2.2.1 Absolute and relative information types 2.2.2 Examples of communicated information types Implementation of required information types 2.3.1 Transformation of information 35 37 38 38 45 45 1.3 1.4