You are here: CSP Developer’s Guide: Overview > 7 Configuring and Using Resources on the DSP Series 2 Cards > Examples for Using PVD/AMD

Examples for Using PVD/AMD

Overview

Prior to using the PVD/AMD feature, you first must have the PVD/AMD function configured on the DSP Series 2 card. Refer to the following examples on how the PVD/AMD feature can be used.

CSP/DSP Series 2 Card

As the events are routed to the host application, the application must make a determination as to whether a person, fax, answering machine, etc. is on the line.

The PVD/AMD events can be received at anytime, so if the application is using these events as triggers to send an API message to the CSP, you must wait for an Acknowledgement to any outstanding API message before issuing a new command for a given span/channel.

Examples of PVD/AMD Feature

Deliver an entire message regardless if it is a person or answering machine

In this example, the application is looking for some initial PVD noise event. On the subsequent falling edge and silence detection, the application starts the message with a Play File Start (0x011B) message. If another rising edge or tone is detected the application issues a Play File Stop (0x0120) message and waits for another silence before playing the message again. The application continues in this loop until the entire message is delivered without noise interruption. This is done by marking the initial noise, waiting for silence, and then issuing the Play File Start message. The application then enters a loop of waiting for the rising edge noise or a play file completed event to release the call.

Deliver two different messages: one for a person and the other for a answering machine

In this example, the application is required to decide on some pre-defined length of noise (for example, <1.5 second but > .25 second) on the first PVD energy detected, followed by some pre-defined length of silence (for example, 1 second) to indicate a person has been detected and issue a Play File Start of the "person" message.

If more noise is detected, the application will stop the Play File Start message, but then have to make another decision on the party (either answering machine or person based on the duration/type of the noise). Any tone detection is considered an answering machine or fax (if 2100 Hz).

Digital Signal Processor
In PPL, a condition that, when met, drives a state machine (PPL Component) from one state to another, by invoking an associated Primitive. In PPL files, an Event is marked by an arrow and text.
Hertz