I found a working solution to connect my Bequem Burner to my PC without direct-cable!
It works this way:
Bequem -> Lantronix comserver -> dlan (powerline) -> my PC
With this solution i can change "Önskad panntemp" and a lot of other parameters, which are usually set on the burners display, from the far!
I can also switch on and off the burner with my PC.
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Burner is connected to Interface via 4 Pins on the electronic print

Interface and comserver are connected via serial cable

Comserver and dlan-adapter are connected via lan cable

Ethernet connection through powerlines in the house (possible up to 200m)

Dlan adapter connected to PC or router via lan cable
On PC installed Software: Lantronix Port redirector creates virtual serial port. This new port is set in supervision software

A video can be found at http://willsmith.badongo.com
(directory: Videos / choose "Download Video"at the bottom )
Some more Info about Supervision can be found here