Hello,
With a second attempt I have now received the SIP data from Sunrise (username and password). I hope that this is the complete SIP data. I then received the product recommendation Gigaset C575A and was told that Dualmultiline is not possible. Whatever that is. I doubt that this is the right product for me. Here's what I want: one phone to be connected to the router on the ground floor and the other landline phone to be connected to the router in the basement (for voip calling). My idea would be to simply enter the SIP data twice. I don't need to be able to make two calls at the same time. Is that possible? Can you recommend a product (Duo) that does not need to be wirelessly coupled to the base? Do I need a SIP service provider? Many thanks for the help, tips, suggestions, etc... Thank you.