LINEMONITORTONE

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.

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

The duration, in milliseconds, during which the tone should be present before a detection is made.

dwFrequency1

dwFrequency2

dwFrequency3

The frequency, in hertz, of a component of the tone. 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 used 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

  Windows NT/2000: Requires Windows NT 4.0 SP3 or later.
  Windows 95/98: Requires Windows 95 or later.
  Version: Requires TAPI 1.4 or later.
  Header: Declared in Tapi.h.

See Also

LINE_MONITORTONE, lineMonitorTones, TSPI_lineMonitorTones