Sadly, no - this UK style phone 'network' design is not used in Germany (traditionally with a central line splitter, splitting DSL and analogue/ ISDN services once, early; nowadays VoIP/ SIP only).
Exactly this, the Fritz!Box hardware contains:
- SIP pbx
- SIP ATA
- cat-iq 2.1 based DECT base station
- some models still support for an analogue phone line coming in, get managed by the internal pbx software and go out (on the FXS port, up to 6 connected DECT handsets - or up to 10 internally registered SIP lines via ethernet/ WLAN)
- some models also still have ISDN hardware (in- and out, including pbx support and all the features above).