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RTCDTMFSender

files/en-us/web/api/rtcdtmfsender/index.md

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{{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