Question about Gigaset E560A ( DE version)

Yes, the Swiss plug is on. UPC Connect Box, like most routers today, simply outputs an analogue interface, so it is also compatible with normal analogue devices.
If you subscribe to a telephone connection with UPC, you should simply be able to plug the telephone directly into the router on the Tel port. however, I would recommend a Gigaset with a separate base, so that the telephone itself can be placed independently of the router. in this case, the charging cradle is also the base and must be placed at the router (or via UKV cabling).