# Call progress functions

Call progress analysis primarily allows the application to control and monitor the placement of outbound calls when not using call control (for example, when using the NOCC protocol). Call progress analysis can also be used at any time after a call is connected. For example, when receiving an inbound call, an application can start up a call progress analysis operation to detect modem tones, fax terminal tones, or voice.

The following ADI functions start and stop call progress analysis:

Function | Synchronous/ Asynchronous | Description
--- | --- | ---
adiStartCallProgress | Asynchronous | Starts call progress analysis.
adiStopCallProgress | Asynchronous | Stops call progress analysis.