Open the communication link to a copter at the given URI and setup the
        connection (download log/parameter TOC).

def open_link(self, link_uri):
        """
        Open the communication link to a copter at the given URI and setup the
        connection (download log/parameter TOC).
        """
        self.connection_requested.call(link_uri)
        self.state = State.INITIALIZED
        self.link_uri = link_uri
        try:
            self.link = cflib.crtp.get_link_driver(
                link_uri, self._link_quality_cb, self._link_error_cb)

            if not self.link:
                message = 'No driver found or malformed URI: {}' \
                    .format(link_uri)
                logger.warning(message)
                self.connection_failed.call(link_uri, message)
            else:
                # Add a callback so we can check that any data is coming
                # back from the copter
                self.packet_received.add_callback(
                    self._check_for_initial_packet_cb)

                self._start_connection_setup()
        except Exception as ex:  # pylint: disable=W0703
            # We want to catch every possible exception here and show
            # it in the user interface
            import traceback

            logger.error("Couldn't load link driver: %s\n\n%s",
                         ex, traceback.format_exc())
            exception_text = "Couldn't load link driver: %s\n\n%s" % (
                ex, traceback.format_exc())
            if self.link:
                self.link.close()
                self.link = None
            self.connection_failed.call(link_uri, exception_text)