David M. Davidson
Chief Engineer, Telephone Systems, Northern Telecom Europe Ltd
David C. Yates
Broadcast Transmission Training Consultant, BBC Transmission
Senior Lecturer, University of Surrey
The basic objective of telephony is to provide a service to enable two customers at a distance to set up a call via the network so that both may talk to each other. The telephone system must supply the means of connecting two telephones together via signalling, ...