code: public SipCall createSipCall() {
      initErrorInfo();
  
      SipCall call = new SipCall(this, myAddress);
  
      callList.add(call);
  
      return call;
    }
docs: This method is used to create a SipCall object for handling one leg of a call. That is, it
  represents an outgoing call leg or an incoming call leg. In a telephone call, there are two
  call legs. The outgoing call leg is the connection from the phone making the call to the
  telephone network. The incoming call leg is a connection from the telephone network to the
  phone being called. For a SIP call, the outbound leg is the user agent originating the call and
  the inbound leg is the user agent receiving the call. The test program can use this method to
  create a SipCall object for handling an incoming call leg or an outgoing call leg. Currently,
  only one SipCall object is supported per SipPhone. In future, when more than one SipCall per
  SipPhone is supported, this method can be called multiple times to create multiple call legs on
  the same SipPhone object.
  
  @return A SipCall object unless an error is encountered.