sendDTMF
Send DTMF. If the call does not exist or has been terminated, a disconnected state will be sent to onCallState
Parameters
context
application context
accountID
account ID
callID
call ID to hang up
dtmfTone
DTMF tone to send (e.g. number from 0 to 9 or # or *). You can send only one DTMF at a time.