(Page 3 of 10 in this chapter)

2.2 An Overview of Application Flow

The typical AG Access application follows a simple sequence of operations in approximately this order: Open an AG driver. The AG driver provides access to the AG hardware for the application. Open a port on the AG board. A port usually equates to a full duplex analog or digital channel and an associated DSP resource. Set parameters (if desired). Start a telephony network protocol. For example, WNK0, wink-start protocol for USA. Establish a call: either wait for an inbound call, or place an outbound call. Monitor call progress and advance to the Connected state. Wait for events. Respond to events by performing operations appropriate for the application's purpose, such as: Playing voice data Recording voice data Detecting DTMF digits Processing unexpected conditions such as extended silence, or sudden hangup Monitor call status and advance to the Disconnected state (hang up), or respond to a hang up by releasing the call.
The application flow is not purely sequential. For example, event monitoring occurs concurrently with voice playback. Use the multitasking capabilities of your operating system and the available processors, including the host PC processor, the AG board's control processor, and the board's DSP processors, to optimize concurrent activities.

2.2.1 Application Management

The AG Access library contains sets of functions that accomplish the following tasks: Application initialization Port initialization Event processing Error handling Parameter management.
These "administrative" functions do not require DSP resources.

(Page 3 of 10 in this chapter)