Many books have been written about the many different manual and automatic systems used throughout the world. These works usually only describe the way a system works. In this publication, not only the differences in principles by which these systems function are distinguished, but also the background to the invention is given. This is done from the perspective of an unbiased international observer. It takes advantage of the vast storehouse of knowledge held by the International Telecommunication Union (ITU). Automatic switching was a typical product of the industrial revolution. The inventors found many ways to accomplish the functions of a manual switchboard. Inventors were prolific. Everything from moving balls in slots and miniature roller coaster carts to robot operators were proposed. This is a good time to examine the successful inventions of the past. Communication networks are now changing from being served by only circuit switches passing signals for telephone and telex to many forms of store and forward switching serving multi-rate digital signals. It is frequently said that as one looks forward one benefits from a review of history so as not to repeat the errors of the past. It is hoped that modern system designers will take time to examine the past.
