NEC 4 manual NECs Tapi Implementation

Using TAPI with NCS Ware 4.0

The service providers implement the telephony functions necessary to write a telephony application as specified in the TSPI. The telephone system manufacturer typically implements this layer so that all the TAPI applications can function with the telephone system. Microsoft implemented the TAPI middleware and this layer aggregates all the service providers available and provides a uniform API to the applications. It also adds value by implementing a few other high level functions. The application layer is where all the applications such as Microsoft Outlook function. These applications are written to TAPI specification so that they can work with any telephone system that has its own service provider.

TAPI functions are of two kinds:

•First party call control functions - these are the functions that control the device directly. These functions are specified in TAPI version 1.4.

•Third-party call control functions - these are functions that instruct a telephone system such as the NCS Serv system to control telephony devices such as trunks and extensions. These functions are specified in TAPI version 2.1.

With Windows 2000, Microsoft released a new version of TAPI called TAPI 3.0 that provides an object oriented API for telephony functions. Even though the application layer specification has been completely rewritten, the service provider interface is compatible with TAPI 2.1. Since NCS Ware implements its service provider based on TAPI 2.1, applications written to TAPI 3.0 can make full use of all the telephony functions implemented by NCS Ware.

NEC's TAPI Implementation

In earlier versions, NEC implemented a TAPI Service Provider (TSP) only and relied completely on Microsoft's middleware to support clients running over a network. However, Microsoft's support for remote clients required that the installation have a complete NT server environment including domains and directory. It required the client systems to belong to the same NT domain, the remote user to have an account on the NT domain, etc. Overall, installing, maintaining and supporting a TAPI-based application resulted in a lot of work and hence made it a very expensive solution.

2TAPI 4.0 User Guide