The subject of computer communications is changing very rapidly. Improvements in terminal access, aligned with the development of timesharing, has brought hands-on experience to a large number of non specialist users. Computer networks have made available vast computing resources and data banks to these users. This book is for anyone familiar with using computers who wishes to understand the techniques used in computer communications. It is also an introduction to the architecture of present day computer communication systems. I would like to thank Roland lbbett, Steve Treadwell, Peter...