code: public String asString(ProcessEvent e, int dptMainNumber, String dptID)
  		throws KNXException
  	{
  		final DPTXlator t = TranslatorTypes.createTranslator(dptMainNumber, dptID);
  		t.setData(e.getASDU());
  		return t.getValue();
  	}
docs: Returns the ASDU of the received process event as datapoint value of the requested
  DPT in String representation.
  <p>
  This method has to be invoked manually by the user (either in
  {@link #groupReadResponse(ProcessEvent)} or
  {@link ProcessListener#groupWrite(ProcessEvent)}), depending on the received
  datapoint type.
  
  @param e the process event with the ASDU to translate
  @param dptMainNumber datapoint type main number, number >= 0; use 0 to infer
  translator type from <code>dptID</code> argument only
  @param dptID datapoint type ID for selecting a particular kind of value translation
  @return the received value of the requested type as String representation
  @throws KNXException on not supported or not available DPT
  @see TranslatorTypes#createTranslator(int, String)