Question about Gigaset C530 Ip

Have a look at this question. Your solution may already be there:

https://www.digitec.ch/de...

I use it with the Fritzbox router as a base station and it works perfectly. It should also work with the Swisscom router, which also has a Dect function.
But just connecting it is not enough, you also need the right settings on the router.

Maybe Swisscom support can help you better here.