Playing a DTMF Tone

You have to configure DevSound in order to play a DTMF tone.

The following settings can be configured before or during DTMF tone play:

• To set the duration of tone on, tone off and tone pause to be used during the DTMF tone playback, use the CMMFDevSound::SetDTMFLengths() method.

  IMPORT_C void SetDTMFLengths(TTimeIntervalMicroSeconds32 &aToneOnLength,
  TTimeIntervalMicroSeconds32 &aToneOffLength, TTimeIntervalMicroSeconds32
  &aPauseLength);

  This method has three parameters:

  • &aToneOnLength - the period over which the tone is to be played.

  • &aToneOffLength - the period over which no tone is to be played.

  • &aPauseLength - the period over which tone playing is to be paused.

  The internal configuration set by CMMFDevSound::SetDTMFLengths() lasts until it is recalled or for the lifetime of the current DevSound.

  Note: The CMMFDevSound::SetDTMFLengths() function is only available during tone play.

• To change the volume of the audio device to a specific value, use the CMMFDevSound::SetVolume() function. The volume can be set to any value from 0 to CMMFDevSound::MaxVolume().

  To define a period over which the volume rises from 0 to the normal volume level, use the CMMFDevSound::SetVolumeRamp() function.

  Note: The CMMFDevSound::SetVolumeRamp() function is only available during tone play.

• To set the speaker balance, use the CMMFDevSound::SetPlayBalanceL() function. This function has two parameters:

  • aLeftPercentage - the left speaker volume percentage.

  • aRightPercentage - the right speaker volume percentage.

• To set the priority setting for this instance of DevSound to access the audio device, use the CMMFDevSound::SetPrioritySettings() method. Priority settings are used by the Audio Policy component to resolve multiple requests to access the audio hardware.