call.sendSIPRawInfo() is used to send SIP INFO messages.
call.sendSIPRawInfo(content_type, content)
Nothing.
call.sendSIPRawInfo() does not raise any events, but on the receiving side wrtc.onSIPRawInfo() event will occur upon reception of a SIP INFO message.
To send a long (1 second) DTMF code 1 outband as a SIP INFO message:
call.sendSIPRawInfo("application/dtmf-relay", "Signal=1\\r\\nDuration=1000");