RTCDTMFSender

{{APIRef("WebRTC")}} 

The RTCDTMFSender interface provides a mechanism for transmitting {{Glossary("DTMF")}}  codes on a WebRTC {{domxref("RTCPeerConnection")}} . You gain access to the connection’s RTCDTMFSender through the {{domxref("RTCRtpSender.dtmf")}}  property on the audio track you wish to send DTMF with.

The primary purpose for WebRTC’s DTMF support is to allow WebRTC-based communication clients to be connected to a public-switched telephone network (PSTN) or other legacy telephone service, including extant voice over IP (VoIP) services. For that reason, DTMF can’t be used between two WebRTC-based devices, because there is no mechanism provided by WebRTC for receiving DTMF codes.

{{InheritanceDiagram}} 

Instance properties

• {{domxref("RTCDTMFSender.canInsertDTMF")}}  {{ReadOnlyInline}} 

  • : A boolean value which is true if the RTCDTMFSender is capable of sending DTMF tones, or false if it is not.

• {{domxref("RTCDTMFSender.toneBuffer")}}  {{ReadOnlyInline}} 

  • : A string which contains the list of DTMF tones currently in the queue to be transmitted (tones which have already been played are no longer included in the string). See {{domxref("RTCDTMFSender.toneBuffer", "toneBuffer")}}  for details on the format of the tone buffer.

Instance methods

• {{domxref("RTCDTMFSender.insertDTMF()")}} 
  • : Given a string describing a set of DTMF codes and, optionally, the duration of and inter-tone gap between the tones, insertDTMF() starts sending the specified tones. Calling insertDTMF() replaces any already-pending tones from the toneBuffer. You can abort sending queued tones by specifying an empty string ("") as the set of tones to play.

Events

Listen to these events using {{domxref("EventTarget.addEventListener", "addEventListener()")}}  or by assigning an event listener to the oneventname property of this interface.

• {{domxref("RTCDTMFSender.tonechange_event", "tonechange")}} 
  • : The tonechange event is sent to the RTCDTMFSender instance’s event handler to indicate that a tone has either started or stopped playing.

Example

See the article Using DTMF with WebRTC for a full example.

Specifications

{{Specifications}} 

Browser compatibility

{{Compat}} 

See also

• WebRTC API
• Using DTMF with WebRTC
• {{domxref("RTCRtpSender.dtmf")}} 
• {{domxref("RTCPeerConnection")}} 
• {{domxref("RTCRtpSender")}}