Background: Our studio is the Fritzbox 7390 and in the living room we wanted our DECT telephone connect (no LAN or telephone line available). The walls of the house were unfortunately so thick that the radio signals could not be carry on. Therefore (LAN on power) is connected to the transmission to the living room of the TP-Link, then came to this little sweet CISCO box. DECT phone connected (was already available), connected to the Fritz box as VoIP and already you could call. Previously I have however still the firmware updated. If you do well - according to Internet. Quality of the language is good.
Settings in Cisco Phone Adapter:
* Proxy: fritz.box (the address at which the HTML page for the Fritz box settings is called)
* User ID: The extension number that is assigned the VoIP phone in the Fritz box when setting up (in my example "621")
* Password: The password that was assigned in the Fritzbox for this VoIP phone - free choice.
I can highly recommend it. Changes to parameters were not necessary for me.