Starts playing a tone to every member of the conference.

DWORD cnfStartTone ( CNFREOURCEHD reshd
DWORD confid,
CNF_TONE_PARMS *parms )

reshd Resource handle returned by cnfOpenResource.

confid Conference identifier returned by cnfCreateConference.

parms Pointer to a CNF_TONE_PARMS structure:

typedef struct
{
DWORD size ;     /* size of this structure              */ 
DWORD freq1;        /* first frequency (Hz)                */ 
INT32 ampl1;         /* level of first tone (dBm)           */ 
DWORD freq2;         /* second frequency (Hz)               */ 
INT32 ampl2;         /* level of second tone (dBm)          */ 
DWORD ontime;        /* on duration of DTMF tone (ms)       */ 
DWORD offtime;       /* off duration of DTMF tone (ms)      */ 
INT32 iterations; /* times to repeat above;              */
                 /* -1 = forever last offtime is        */
                 /* trimmed if repeat>1                 */ 
} CNF_TONE_PARMS; 

See the Details section for a description of these fields.

• SUCCESS
• CTAERR_BOARD_ERROR
  The tone cannot be generated because the board stopped responding.
• CNFERR_CONFERENCE_EMPTY
  The conference confid currently has no members.
• CTAERR_INVALID_HANDLE
  reshd is not a valid conferencing handle.
• CNFERR_INVALID_IDENTIFIER
  confid is not a valid conference identifier.
• CNFERR_INVALID_PARAMETER
  parms is inconsistent or out of range.

• CNFEVN_TONE_DONE
  Tone generation completed or was stopped. Generated only if event_mask is set to CNF_EVNMSK_TONE_DONE when the function is called, and if the function returns SUCCESS.

This function plays a tone to all members currently attending the conference designated by confid. When this function is invoked, members stops hearing each other and hear only the tone.

The CNF_TONE_PARMS structure contains the following fields:

Field	Description
freq1	The first of two frequencies or the only frequency of the tone to be generated (in Hz).
ampl1	The amplitude (in dBm) of the first frequency.
freq2	The second frequency (in Hz) if the tone to be generated contains two frequencies, or zero otherwise.
ampl2	The amplitude (in dBm) of the second frequency.
ontime	The duration (in ms) of the tone.
offtime	The duration (in ms) of silence to follow the tone; specify 0 for no offtime.
iterations	The number of times to repeat the tone (and silence period); specify -1 to repeat a cadence tone forever.

If the iterations count is one (1), the tone is not complete until the offtime has expired. If the iterations count is more than one, then the final offtime is omitted.

To generate a tone continuously (i.e. forever), set iterations to -1 and specify an offtime of 0 (zero). Use the cnfStopTone command to terminate tone generation prematurely.

For more information, refer to Section 4.9, Playing a Tone.

cnfStopTone

extern CNFRESOURCEHD cnfresourcehd;

int myConferenceTone( DWORD confid )
{
 CTA_EVENT event;
 CNF_TONE_PARMS toneparms;

 // Fill the tone structure
 toneparms.size = sizeof(CNF_TONE_PARMS);
 toneparms.freq1 = 1000;
 toneparms.ampl1 = -20;
 toneparms.freq2 = 500;
 toneparms.ampl2 = -20;
 toneparms.ontime = 200;
 toneparms.offtime = 200;
 toneparms.iterations = 2;

 cnfStartTone ( cnfresourcehd, confid, &toneparms);

    do 
    {
        myGetEvent( &event );        /* see ctaWaitEvent example */
    } while( event.id != CNFEVN_TONE_DONE );

    if( CTA_IS_ERROR( event.value ) )
        return MYFAILURE;            /* API error                */
    else
        return SUCCESS;              /* started successfully     */
}