1.1 Introduction

1.2 ADI Service Overview

1.3 Basic Terminology

1.1 Introduction

This manual documents the use of the CT Access ADI service for building computer telephony applications, and provides detailed descriptions of its capabilities and functions. This reference manual should be used in conjunction with the ADI Service Developer's Manual and the CT Access Developer's Reference Manual.

This document is intended for developers of telephony and voice applications who are getting started (or developing) with CT Access. This document defines telephony terms where applicable, but assumes that the reader is familiar with telephony concepts and the C programming language.

1.2 ADI Service Overview

CT Access is a development environment providing standard programming interfaces for telephony functions that are hardware-independent. Refer to the CT Access Developer's Reference Manual and to the ADI Service Developer's Manual for more information about CT Access and setting up the CT Access environment.

The ADI service is a C function library component of CT Access that enables application programs to execute multiple telephony functions on the Natural MicroSystems (NMS) AG and CG hardware. Functions include call control (now superseded by the Natural Call Control service), voice record and playback, digit (DTMF) collection, as well as other generator and detector capabilities. The ADI service supports the NMS QX family of hardware. Refer to the QX 2000 Installation and Developer's Manual for more information on the QX 2000 boards.

The CT Access environment gives you a standard interface to use resources on NMS telephony boards. By using the extensive telephony functions in CT Access along with the Natural Media libraries, you can develop a comprehensive range of telephony applications.

1.3 Basic Terminology

Familiarize yourself with the following terms and concepts as you work with CT Access and the ADI service. Some of the most frequently used terms in this manual are used in a way specific to CT Access and to the ADI service.

A port is the object on which telephony functions are performed, and contains physical and logical resources on the board. A port is represented by a CTA context and a context handle (ctahd), a software handle that enables the application (and its developer) to keep track of software activities. This manual refers to ports and contexts almost interchangeably, but keep in mind that the term port connotes an object, typically connected to a telephony network and used to process calls, and the term context refers to a software handle.

To access most functionality on a port, the application must associate a telephony protocol with the port. On AG hardware, the telephony protocol is embodied by a Trunk Control Program (TCP), and must be loaded during board initialization. NMS provides TCPs for most standard telephone line interfaces. Starting a protocol enables the use of call control functions. Almost all functions require a protocol to be loaded. For applications that do not use call control functions, or choose to manage the line interface manually, a special TCP is provided called NOCC for No Call Control. On QX hardware, the telephony protocol is embodied by a Dynamic Link Library (DLL), and is loaded when calling adiStartProtocol.

For more information about controlling calls under specific TCPs, refer to the
AG CAS for ADI Service Installation and Developer's Manual.

In this manual, operation refers to an active process, such as a recording operation, or a digit collecting operation. Function refers specifically to a function call.