1) Connect serial-usb device to AVM 7270 usb interface. Device and interface
   properties are not unique. Therefore, each device must be aliased to the
	the proper module, if not already working properly.

   usb \  usb_endpoint  \   usb   \  usb_endpoint  \  usb_endpoint  \
   1-1 / usbdev1.4_ep00 / 1-1:1.0 / usbdev1.4_ep81 / usbdev1.4_ep02 /
         -------+------                             -------+------
                !                                          !
					 +----------- announce device discovery     !
                                                           !
                                    load pl2303 -----------+

    usb_endpoint  \ usb_device
   usbdev1.4_ep83 /  usbdev1.4

   usbdev1.4_ep02/device/modalias
	usb:v067Bp2303d0300dc00dsc00dp00icFFisc00ip00

   alias usb:v067Bp2303d0300dc00dsc00dp00icFFisc00ip00 pl2303


2) Load pl2303 driver. The drivers/pl2303 events have different DEVPATHs.

     module  \  drivers  \ module \ drivers \ drivers \ usb-serial \   tty
   usbserial / usbserial / pl2303 /  pl2303 /  pl2303 /   ttyUSB0  / ttyUSB0