LINEMONITORTONE structure (tapi.h)

The LINEMONITORTONE structure describes a tone to be monitored. This is used as an entry in an array. The lineMonitorTones and TSPI_lineMonitorTones functions use this structure.

Syntax

typedef struct linemonitortone_tag {
  DWORD dwAppSpecific;
  DWORD dwDuration;
  DWORD dwFrequency1;
  DWORD dwFrequency2;
  DWORD dwFrequency3;
} LINEMONITORTONE, *LPLINEMONITORTONE;

Members

dwAppSpecific

Used by the application for tagging the tone. When this tone is detected, the value of the dwAppSpecific member is passed back to the application.

dwDuration

Duration of time during which the tone should be present before a detection is made, in milliseconds.

dwFrequency1

First frequency of the tone, in hertz.

dwFrequency2

Second frequency of the tone, in hertz.

dwFrequency3

Third frequency of the tone, in hertz. If fewer than three frequencies are needed in the tone, a value of 0 should be used for the unused frequencies. A tone with all three frequencies set to zero is interpreted as silence and can be use for silence detection.

Remarks

This structure may not be extended.

The LINEMONITORTONE structure defines a tone for the purpose of detection. An array of tones is passed to the lineMonitorTones function which monitors these tones and sends a LINE_MONITORTONE message to the application when a detection is made.

A tone with all frequencies set to zero corresponds to silence. An application can thus monitor the call's information stream for silence.

Requirements

Requirement	Value
Header	tapi.h

See also

LINE_MONITORTONE

TSPI_lineMonitorTones

lineMonitorTones