code: public void close()
  	{
  		synchronized (this) {
  			if (closed)
  				return;
  			closed = true;
  		}
  		try {
  			normalMode();
  		}
  		catch (final KNXException e) {
  			logger.error("could not switch BCU back to normal mode", e);
  		}
  		conn.close();
  		notifier.quit();
  	}
docs: /* (non-Javadoc)
  @see tuwien.auto.calimero.link.KNXNetworkLink#close()