CUL

flash CUL_V3.hex (from [http://www.atmel.com/ Atmel] page)
attach CUL to Fritz!Box (with a USB Hub to have USB-Memory stick and CUL running at the same time)

Note: to check if CUL works enable in FritzBox settings USB-Fernanschluss. 
Now it gets recognized as CUL868.
Remember to disable it again. 
The CUL should be recognized as "Es handelt sich um ein nicht unterstütztes USB-Gerät." 
This is OK!

Fritz!Box 7240

Update Fritz!Box to Firmware-Version >= 73.05.05
download [http://www.fhem.de http://www.fhem.de]
unzip and store at root of your USB-Memory stick in the folder "fhem" (this will be "/var/InternerSpeicher/<yourUsbStickName>/fhem/" on you Fritz!Box later on.
adapt in this folder the file "startfhem" if you use more then 1 storage device (e.g. USB memory stick and "1&1 Online Speicher") with hardcoded destination folder for your fhem path:
home=/var/InternerSpeicher/SanDisk-Cruzer-01/fhem
Alternatively disable "1&1 Online Speicher" and use USB memory stick only. This way you don't have to adapt startfhem.
to use telnet enable with phone dialing #96*7*. To login use same password as for Fritz!Box webfrontend. Now you can edit all of your files using vi in telnet.
Now define your "fhem.cfg" to match your configuration, e.g. starting with your housecode:
define myCUL CUL /dev/ttyACM0 1234

...
finally start fhem in telnet:
/var/InternerSpeicher/SanDisk-Cruzer-01/fhem/startfhem
or use autostart => see [#Autostart_fhem #Autostart fhem]

Open issues

Daily resets with big log files

After 1 week running perfectly I was seeing regular/daily resets. The problem in my setting is that I am using several <a href="/w/index.php?title=FS20-STR&action=edit&redlink=1" class="new" title="FS20-STR (Seite nicht vorhanden)">FS20-STR</a>. These devices send every 2-3 minutes off-for-timer or on-for-timers signals. These events get logged in the monthly log file. After this log was bigger then 1MB I have seen these resets. After I emptied/deleted the file the box is running stable again.--Benutzer:Madu99

After looking more into this, it seems that the 7240 gets a memory problem when log files gets bigger then ~800KB. I changed the logging from monthly files to weekly files (using ./log/fhem-%Y-%m-%V.log). This way files should never get this big. Since then 7240 runs stable without any problems.--Benutzer:Madu99 01:44, 29. Dez. 2011 (CET)