public boolean isXmtBusy(){
  if (controller == null) {
    return false;
  }
  return (!controller.okToSend());
}

public boolean isXmtBusy ( ) { if ( controller == null ) { return false ; } return ( ! controller . okToSend ( ) ) ; }
implement abstract method to signal if there ' s a backlog of information waiting to be sent .
