Telecommunications switch having a universal applications program interface for stantardized interactive call processing communications

The present invention is a universal host-to-switch application program interface (API) utilizing a generic message format for performing call control processing and capable of being customized to meet telecommunications application and network signalling protocol requirements. The generic message formats have programmable fields for transmitting commands, status, and data between the host application and the switch. The present invention further comprises a programmable telecommunication switch that provides a user with the ability to define a desired signalling protocol, either "standard" or custom in nature, for performing any desired switching functions. The present invention includes a protocol development environment which enables a user to define a separate finite state machine for each port provided by the switch. Each finite state machine may be independently defined by combining a series of elementary processing steps, called atomic functions, into primitives, which are in turn combined with states and events to define the desired state machine. Such state machines may include atomic functions configured to generate predetermined messages under predetermined conditions and containing predetermined information. Such state machines may further include the ability to respond to state events that include the receipt of generic API messages configured to provide the state machine with information from the host application.