RTCDTMFSender: toneBuffer property
The RTCDTMFSender
interface's toneBuffer property returns a string
containing a list of the DTMF tones currently queued for sending to the
remote peer over the RTCPeerConnection
. To place tones into the buffer,
call insertDTMF()
.
Tones are removed from the string as they're played, so only upcoming tones are listed.
Value
A string listing the tones to be played. If the string is empty, there are no tones pending.
Exceptions
InvalidCharacterError
DOMException
-
Thrown if a character is not a DTMF tone character (
0-9
,A-D
,#
, or,
).
Tone buffer format
The tone buffer is a string which can contain any combination of the characters that are permitted by the DTMF standard.
DTMF tone characters
- The digits 0-9
-
These characters represent the digit keys on a telephone keypad.
- The letters A-D
-
These characters represent the "A" through "D" keys which are part of the DTMF standard but not included on most telephones. These are not interpreted as digits. Lower-case "a"-"d" automatically gets converted to upper-case.
- The pound/hash sign ("#") and the asterisk ("*")
-
These correspond to the similarly-labeled keys which are typically on the bottom row of the telephone keypad.
- The comma (",")
-
This character instructs the dialing process to pause for two seconds before sending the next character in the buffer.
Note:
All other characters are unrecognized and will cause
insertDTMF()
to throw an
InvalidCharacterError
DOMException
.
Using tone buffer strings
For example, if you're writing code to control a voicemail system by sending DTMF
codes, you might use a string such as "*,1,5555"
. In this example, we would send "*"
to
request access to the VM system, then, after a pause, send a "1" to start playback of
voicemail messages, then after a pause, dial "5555" as a PIN number to open the
messages.
Setting the tone buffer to an empty string (""
) cancels any pending DTMF
codes.
Example
tbd
Specifications
Specification |
---|
WebRTC: Real-Time Communication in Browsers # dom-RTCDTMFSender-tonebuffer |
Browser compatibility
BCD tables only load in the browser