Actually, the WLAN stick should be operated on the receiver (ET4000). After I had finally found the correct driver for the box, I realized that the connection quality to be desired extremely leaves much! The router is only 5 m far away and in between is only one door - also tested in the living room allows the connection to be desired. Tested with a AVM Stick and everything runs fine. Maybe the key is functioning properly if the router is not quite so far away? For me, the stick unfortunately unusable - shame, especially since the small size might be better than beneficial.
