Standard ECMA-179
Services for Computer Supported Telecommunications Applications (CSTA) - Phase I

(June 1992)

This ECMA Standard has been developed by ECMA/TC32-TG11

This Standard defines Services and Event Reports for the area of Computer-Supported Telecommunications Applications (CSTA).

Thus it is focused on the provision of an application service interface between a Switching Function and a Computing Function. The CSTA application interface is intended to be disassociated from the various user-network interfaces or network-network interfaces CSTA applications may serve, observe or manipulate. Because CSTAoperates with existing telecommunications interfaces indirectly, it can and does operate generically, so that the differences between 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 are described in Technical Report ECMA TR/52, Computer-Supported Telecommunications Applications. To enable these services CSTAprovides an OSI Application Layer Protocol supporting a peer-to-peer relationship between computing and telecommunications networks. This protocol is defined in Standard ECMA-180. Each instance of any Service, and every instance of some types of Services are defined as client-server relationships.

CSTA Services allow functional integration between a computing network and a telecommunications network. However, the computing platforms that support these functionally integrated applications, or their Application Programming Interfaces (APIs), are outside the scope of this Standard.

Communication between the computing and switching networks may take place via intervening networks which range from a simple point-to-point connection to a local or wide area communications network.

It is possible for ISDN based networks, e.g. Private Telecommunications Networks (PTNs), to provide support for CSTA applications, however there are limitations in both this Standard and current ISDN standards that limit the extent of this support. Thus, based upon current standards there can be limitations on the use of PTNs for CSTA users.

Further information on the CSTAtopic is also available.