Open Service Access (OSA); Web Services Application Programming Interface (API) for OSA; Parlay X services
The present document specifies an initial set of Parlay X Web Services. For each selected Web Service, this document describes the motivation for its inclusion, the commercial and technical rationale, and an illustrative usage scenario(s).  This document also specifies the message(s) exchanged during invocations of each Web Service, by defining the semantics in English and the syntax using W3C WSDL.
The OSA APIs are designed to enable creation of telephony applications as well as to "telecom-enable" IT applications.  IT developers, who develop and deploy applications outside the traditional telecommunications network space and business model, are viewed as crucial for creating a dramatic whole-market growth in next generation applications, services and networks.
The Parlay X Web Services are intended to stimulate the development of next generation network applications by developers in the IT community who are not necessarily experts in telephony or telecommunications. The selection of Web Services should be driven by commercial utility and not necessarily by technical elegance. The goal is to define a set of powerful yet simple, highly abstracted, imaginative, telecommunications capabilities that developers in the IT community can both quickly comprehend and use to generate new, innovative applications.