1. A universal applications program interface (API) for standardized interactive call processing communications between functional layers of a telecommunications system including a telecommunications switch and a host device coupled to the switch, comprising: a first message having user-programmable functionality for transferring all call control processing commands and data from said host to said functional layers of said telecommunications switch; a second message having user-programmable functionality for transferring all call control processing status and data from said functional layers of said telecommunications switch to said host; and one or more instantiations of one or more programmable protocol (PPL) component state machines each of which represents a call processing protocol, each said one or more PPL component state machines comprising (i) one or more libraries each containing one or more atomic functions having associated therewith user-specified data, (ii) one or more predetermined logical states, which may be user-definable, (iii) at least one predetermined event associated with each said one or more logical states, each said at least one predetermined event uniquely identified relative to each said one or more PPL component state machines, and (iv) user-definable primitives each of which comprises a user-defined sequence of atomic functions, each said primitive being invoked upon the occurrence of said at least one predetermined event in such a manner that said at least one predetermined event includes receipt of said first message and wherein at least one of said one or more atomic functions generates said second message.