As demands for new telephone services for intelligent networks are rising, constructing services with predefined building blocks appears to be a viable recipe to rapidly provide new services. Therefore, attempts to formally describe those building blocks independently of service types are being made.
In this thesis, in order to describe precisely the services, a new formal specification notation, called $Z_t$, has been designed by incorporating history concept into a general purpose specification language Z. We have specified the Service Independent Building Blocks as defined by CCITT using $Z_t$ to demonstrate the adequacy of its expressiveness. We have compared specifications prepared in $Z_t$ with specifications written in SDL which has been widely used in describing SIBs.
