The telephone is a landline telephone with an analogue connection, which means that it cannot be connected directly to an IP router such as the Swisscom Internet Box. It requires a DECT base or an analogue connection. If you have another model like the CL660HX that is based on DECT, it could work on a DECT-enabled router like the Swisscom Internet Box. However, this is not the case for the CL660 Duo.