One device
+If you connect one USB device (FHZ1000PC, FHZ1300PC, EM1010PC, WS300, ...)
+to your GNU/Linux server you can use the regular ftdi_sio kernel module.
+However, it may not recognize our device. Therefore you need to get the
+vendor and product codes:
+
+# lsusb
+...
+Bus 002 Device 002: ID 0403:e0e8 Future Technology Devices International, Ltd
+...
+
+Now you need to edit your /etc/modprobe.conf or
+/etc/modprobe.conf.local file (depending on your distribution).
+Add the following line to it:
+
+
+options ftdi_sio vendor=0x0403 product=0xe0e8
+
+Replace the vendor and product code with the output of the lsusb command.
+The you load the module using:
+
+# modprobe ftdi_sio
+
+
+
Multiple devices
+If you're using multiple USB devices (FHZ1000PC, FHZ1300PC, EM1010PC, WS300, ...)
+you cannot use the methode above. You need to modify the ftdi_sio kernel module
+to make it work. The following example was done with openSuSE 10.1:
+You need to have the kernel-source-version RPM of your
+current kernel (see output of uname -r) installed.
+
+# cd /usr/src/linux
+# make cloneconfig
+# make modules_prepare
+# cp /boot/symvers-2.6.*-default.gz /usr/src/linux
+# mv symvers-2.6.*-default.gz Module.symvers.gz
+# gunzip /usr/src/linux/Module.symvers.gz
+# make modules_prepare
+# cd drivers/usb/serial
+
+# vi ftdi_sio.h
+...
+#define FTDI_ELV_WS500_PID 0xE0E9 /* PC-Wetterstation (WS 500) */
+#define FTDI_ELV_EM1010PC_PID 0xE0EF /* EM 1010 PC */
+
+Now we need to uncomment some lines to enable all of our devices.
+
+# vi ftdi_sio.c
+...
+ { USB_DEVICE(FTDI_VID, FTDI_ELV_WS300PC_PID) },
+ { USB_DEVICE(FTDI_VID, FTDI_ELV_FHZ1300PC_PID) },
+ { USB_DEVICE(FTDI_VID, FTDI_ELV_WS500_PID) },
+ { USB_DEVICE(FTDI_VID, FTDI_ELV_EM1010PC_PID) },
+...
+
+Remove the /* and */ of your devices and save the file.
+
+# cd /usr/src/linux
+# make modules
+...
+
+# cd /lib/modules/yourKernelVerion/kernel/drivers/usb/serial
+# cp ftdi_sio.ko ftdi_sio.ko_backup
+# cp /usr/src/linux/drivers/usb/serial/ftdi_sio.ko .
+
+To make it become active you may need to stop applications (like fhem) who
+are using the /dev/ttyUSB device and unload the module and load it again.
+
+# rmmod ftdi_so
+# modprobe ftdi_so
+
+You should now see multiple ttyUSB devices:
+
+# ls -l /dev/ttyUSB*
+crw-rw---- 1 root uucp 188, 0 2007-02-11 23:00 /dev/ttyUSB0
+crw-rw---- 1 root uucp 188, 1 2007-02-11 23:00 /dev/ttyUSB1
+
+
+
Device links
+If you're using multiple USB devices (FHZ, EM, WS...) it might occur that the
+enumeration of the /dev/ttyUSBn numbers get mixed up if one of the
+device is missing or after a reboot.
+Starting with kernel 2.6 the UDEV implements means for using virtual names
+instead of the bare numbers.
+Edit the file /etc/udev/rules.d/50-udev-default.rules
+and append the following lines in the block labled as serial devices:
+
+
+KERNEL=="ttyUSB*", SYSFS{product}=="ELV FHZ 1300 PC", SYMLINK+="elv_fhz1300pc"
+KERNEL=="ttyUSB*", SYSFS{product}=="ELV EM 1010 PC", SYMLINK+="elv_em1010pc"
+
+Now you need to reboot your box (unfortunalty) and once the system has come up
+again you can use the device paths /dev/elv_fhz1300pc or
+/dev/elv_em1010pc in your FHEM configuration file.
+
+