Call processing system and method for providing a variety of messaging

Abstract

A flexible, object-oriented call processor is employed in a wide range of messaging environments (e.g. voice messaging, facsimile mail, notification and electronic mail) to provide any number and type of messaging service. Call processing procedures can be changed or adapted to provide a new or different messaging service without rewriting large amounts of software or redesigning the messaging system. Various call processing primitives are established to perform various call processing services in a messaging application, with each to primitive performing a single operation. Sets of parameters are also defined for different types of call processing services and different subscribers. A service state table corresponding to a sequence of logical states is set up to provide the requested call processing service. Once a requested call processing service is identified in response to a subscriber call, the call processor executes the service logic in the corresponding service state table. Each primitive is associated with a state in the service state table and is a source of events from that state. Execution of each logical state invokes one primitive for transitioning to the next state in the state table. Using such primitives and parameters, call processing services may be configured and readily adapted without knowledge of specific operating system or application software. A unique layered software architecture called the call processing stack executes call processing services based on corresponding records of configured primitives and parameters. Each layer of the architecture performs dedicated tasks without specific knowledge of the functions of the other layers.