Signalling is the life-blood of telecommunications and common-channel signalling is the key to providing flexible and cost-effective services to customers. This book commences with the basics of signalling and then unveils the complexities of common-channel signalling systems. The book is written to i appeal to a wide range of readership. The novice can build up a comprehensive understanding of signalling by systematically making progress through the book. Experts in telecommunications who wish to understand the specialist subject can select appropriate text@ guided by the chapter summaries. Experts in signalling will find the book useful in extending their knowledge of a very broad subject. The glossary cuts through the maze of jargon. The book describes basic principles@ channel-associated signalling systems and the CCITT Signalling System No. 6. However@ the focus of the book is upon common-channel signalling and CCITT Signalling System No. 7 and the Digital Subscriber Signalling System No. 1 are described in detail. The latest techniques are explained including@ for example@ the form of signalling required for gaining access to remote databases. The interworking of common-channel signalling systems is also described. Author Richard J. Manterfield