Hello,
Connecting an Alcatel F890 Voice to the Livebox 5 is possible
You just need to follow the manual pairing procedure for a handset and finally press the WPS button on the Livebox (instead of pressing the "paging" button on the Alcatel base)
For the procedure to follow, on the handset, see the manual on pages 18 and 19
§ Easy registration of an additional handset
Note: Once the handset is paired with the Livebox, its new "base" is the Livebox, all functionalities associated with the Alcatel base are no longer active...
Among other things, the integrated answering machine on the base will no longer work.
The F890 base is only used as a charger.
The manual for the F890 Voice:
https://www.alcatel-home.com/sites/default/files/product/1360/files/alcatel-phones-f890-voice-guide-utilisateur-doc-frrev5.pdf Very difficult to catch a black cat in a dark room.
Especially when it's not there...