The insertDTMF() method on the RTCDTMFSender interface starts sending DTMF tones to the remote peer over the RTCPeerConnection. Sending of the tones is performed asynchronously, with tonechange events sent to the RTCDTMFSender every time a tone starts or ends.

As long as the connection is active, you can send tones at any time. Calling insertDTMF() will append the specified tones to the end of the current tone buffer, so that those tones play after the previously-enqueued tones.


RTCDTMFSender.insertDTMF(tones[, duration[, interToneGap]]);


A DOMString containing the DTMF codes to be transmitted to the recipient. Specifying an empty string as the tones parameter clears the tone buffer, aborting any currently queued tones. A "," character inserts a two second delay.
duration Optional
The amount of time, in milliseconds, that each DTMF tone should last. This value must be between 40 ms and 6000 ms (6 seconds), inclusive. The default is 100 ms.
interToneGap Optional
The length of time, in milliseconds, to wait between tones. The browser will enforce a minimum value of 30 ms (that is, if you specify a lower value, 30 ms will be used instead); the default is 70 ms.

Return value



The DTMF tones couldn't be sent because the track has been stopped, or is in a read-only or inactive state.
One or more of the characters in tones is not valid DTMF.




Specification Status Comment
WebRTC 1.0: Real-time Communication Between Browsers
The definition of 'RTCDTMFSender.insertDTMF()' in that specification.
Candidate Recommendation

Browser compatibility

ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
insertDTMFChrome Full support 27Edge Full support ≤79Firefox Full support 52IE No support NoOpera Full support YesSafari ? WebView Android Full support 4.4Chrome Android Full support 27Firefox Android Full support 52Opera Android Full support YesSafari iOS ? Samsung Internet Android Full support 1.5


Full support
Full support
No support
No support
Compatibility unknown
Compatibility unknown

See also