I use it on a Freebox Revolution and I saw two concerns: - In DECT and bypassing the base of the phone, disconnect it is very often the Freebox. It quickly becomes painful - RJ11 connected directly to the box, it becomes very occasional but it happens
Ca or just a problem of compatibility (which I doubt) or it is side freebox. In all cases, a reboot of the box (for DECT mode) premet on the phone to be recognized again. RJ11 and it eventually returns to be the same.