OpenWRT Router for new user with reliable and long support

[dnd]

@Disk1313

Are you sure that the analogue connector does not work

Did some digging, and now I'm not so sure anymore

Check this post and the following:

Rj11 voip configuration

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 register…

So if using OpenWrt directly on the Fritzbox, you have to replace that SIP/VoIP server part.
This would be Asterisk.
https://openwrt.org/docs/guide-user/services/voip/asterisk