manual: hwgrep is the preferred way of specifying a serial device

fallen · fallen · commit f0dddd9f391d · 2015-06-23T18:14:25.000+02:00
diff --git a/doc/manual/faq.rst b/doc/manual/faq.rst
@@ -89,4 +89,8 @@ feature of pyserial
 `serial_for_url() <http://pyserial.sourceforge.net/pyserial_api.html#serial.serial_for_url>`_
 in order to open a serial device.
 
+The preferred way to specify a serial device is to make use of the ``hwgrep://``
+URL: it allows to select the serial device by its USB vendor ID, product
+ID and/or serial number. Those never change, unlike the device file name.
+
 See the :ref:`TDC001 documentation <tdc001-controller-usage-example>` for an example of ``hwgrep://`` usage.
