Definition
WebRTC: Real-Time Communication in Browsers defines RTCDTMFSender
[Exposed=Window]
interface RTCDTMFSender : EventTarget {
undefined insertDTMF(DOMString tones, optional unsigned long duration = 100, optional unsigned long interToneGap = 70);
attribute EventHandler ontonechange;
readonly attribute boolean canInsertDTMF;
readonly attribute DOMString toneBuffer;
};