Only PCs (Win 7, Win Vista and Lubuntu) did not find the net!
After repeated switching off and on the network was found by the PC and automatically connected.
On nächhsten day when booting the PC's the same game. No network? Only Android devices were connected.
Even repeated switching on and off / reboot - all without success.
Vodafone hotline knew no advice. Was on 2nd level support referred (0900 number, 1.24 / min).
Did the old router reactivated (Vodafone 602) and incorporated the new scrap in the basement.
Design of the old router (small, not stupid LED Design) was better anyway.
Steer clear of the the Vodafone DSL904!
NOTE: On 30.04.2015 a new firmware released! Now that wireless connectivity has been upgraded with Windows PCs appear. Since I could no longer watch the effect.