... However, the device is not entirely trivial. My idea was to operate an old W48 Wählscheibentelefon at a Fritz box. However, I had to go the detour over Powerlan adapter, since all network sockets are in the wrong place in the room. I have tried everything possible to find the right Fritzbox settings on the network. The manual is for a tech savvy, however VOIP newbie, not easy to understand. Remedy: Take a well-known search engine and are a "HT701 Fritz box". Since you will find a private site with a very good step by step guide. Voila!