# Setting up the environment

Before building applications using the SIP for NCC API, install NaturalAccess and SIP for NCC with a valid license on your system. SIP for NCC applications use the NaturalAccess development environment for exchanging data with a SIP for NCC server.

The following illustration shows an overview of NaturalAccess components and how they relate to the SIP implementation:

## NaturalAccess features

NaturalAccess provides:

- A standard hardware-independent application programming interface.

- Sets of call control and media functions grouped into logical services.

- An interface for accessing and changing service parameters.

- Error trapping features.

- An architecture that supports as-needed resource allocation.

- Support for both single-threaded and multi-threaded programming models to meet a variety of application program requirements.

- Multiple operating system support.

## Contexts and event queues

NaturalAccess organizes services and accompanying resources around a single processing context. A context usually represents an application instance controlling a single call.

An event queue is the communication path from a NaturalAccess service to an application. A NaturalAccess service generates events that indicate specific conditions or state changes and sends them to applications through the event queue.

## NaturalAccess services

NaturalAccess services provide functions for establishing and maintaining network connections, determining call status, playing and recording voice messages, generating and detecting DTMF and tones, and controlling CT bus switching. Refer to the Dialogic® NaturalAccess™ Software Developer’s Manual for a list of available NaturalAccess services.

## Fusion

Fusion enables applications to perform media stream processing required for IVR tasks such as providing voice prompts, detecting and generating DTMF digits, or using speech recognition to query or deliver information.