Question about FRITZ! Box 6590 Cable DE version

As already written, there is no router freedom in Switzerland and the Swiss providers often behave restrictively. Unfortunately, I can only say something specific about Rii Seez Net. The adaptation to the network is not supposed to be easy and that's why Rii Seez Net doesn't do it. Unfortunately, they are not very credible as they sell the Fritz Box themselves if you want to operate a VOIP / ISDN telephone system. Besides, the Swiss network operators don't buy anything else that the rest of the world doesn't buy either. They just don't want it, I just don't understand why ? In Germany, by the way, it was exactly the same until the network agency passed a law obliging all providers to allow all routers. Yes, apparently it did work, it just needed a bit of political pressure.