Standard ECMA-217
Services for Computer Supported Telecommunications Applications (CSTA) - Phase II

(December 1994)

Services and Event Reports supported by Computer Supported Telecommunications Applications (CSTA) Phase II are defined in this Standard.

It is focused on providing an application service interface between a Switching Function and a Computing Function. The CSTA application interface is disassociated from the various user-network interfaces and network-network interfaces CSTA applications may serve, observe or manipulate. Because CSTAoperates with existing telecommunications interfaces indirectly, it operates generically, so that differences among various existing interfaces are hidden from CSTA applications. Support of user-to-network interfaces is outside the scope of CSTA.

The individual Services needed to support the CSTA applications that are described in ECMA TR/52, Computer Supported Telecommunications Applications, are covered in this Standard. To enable these Services CSTAprovides an OSI Application Layer Protocol that supports a peer-to-peer relationship between computing and telecommunications networks. This protocol is defined in Standard ECMA-218. Every instance of each CSTA Service is a client-server relationship.

CSTA Services allow functional integration between a computing network and a telecommunications network. However, the specification of Computing platforms (i.e. Application Programming Interfaces - APIs) that support such functionally-integrated applications are outside the scope of this Standard.

Communication between the computing and switching (i.e. telecommunications) networks may take place via intervening networks ranging from simple point-to-point connections to local- or wide-area telecommunications networks.

A companion Technical Report ECMA TR/68, CSTA Scenarios, illustrates practical applications of CSTA Services to implement common call handling and monitoring procedures. ECMA TR/68is intended to serve as a guide to better understanding of CSTA and provides recommended (but not mandatory) examples of Service Requests with particular parameter values and Event Reports associated with typical CSTA-based procedures.

Phase II of CSTA extendsthe range of features offered by CSTA Phase I.

Both Phase I and Phase II specifications are based upon the original concepts described in Technical Report ECMA TR/52, Computer-Supported Telecommunications Applications.

Further information on the CSTAtopic is also available.

The above files are included in the current version of the ECMA CD-ROM. The CD-ROM and printed copies of this Standard can be ordered, free of charge, from documents@ecma.ch