Returns all FTDI devices matching our vendor and product IDs.

        :returns: list of devices
        :raises: :py:class:`~alarmdecoder.util.CommError`

def find_all(cls, vid=None, pid=None):
        """
        Returns all FTDI devices matching our vendor and product IDs.

        :returns: list of devices
        :raises: :py:class:`~alarmdecoder.util.CommError`
        """
        if not have_pyftdi:
            raise ImportError('The USBDevice class has been disabled due to missing requirement: pyftdi or pyusb.')

        cls.__devices = []

        query = cls.PRODUCT_IDS
        if vid and pid:
            query = [(vid, pid)]

        try:
            cls.__devices = Ftdi.find_all(query, nocache=True)

        except (usb.core.USBError, FtdiError) as err:
            raise CommError('Error enumerating AD2USB devices: {0}'.format(str(err)), err)

        return cls.__devices