Only evil fallen flat on its face, but then with "conciliatory" end

I use two of these FritzFone to my FritzBox 7390th

To mention, however, that the calls with the phones to not even been possible. I had constant disconnections, feedback, and a rattle and whimpering.
After consultation with the AVM support, my pretty new Fritz box 7390 has been exchanged directly (by hand exchange by the postman), because the assumption was that the DECT receiver of the modem is defective. Unfortunately, there was a problem with brand new Fritzbox exactly.

I was already on the verge of Amazon to send everything back. Fortunately, I had again sat down with the support of AVM bank, giving came out that I had an old analog connector at Telecom. Say the DSL signal must be disconnected from the telephone signal via splitter. And on notice of AVM came out then that especially the Fritz box 7390, which theoretically capable of is a digital DECT telephone while convert signal into an analog signal, but somehow it does not work properly.

In short, I have changed my contract with the Telecom and now have a VoIP connection, which was anyway at the time because I wanted change of 6,000 points on 16.000er DSL.
Herewith the FritzFone work very well.
Only it should be noted that in the telephony via speakerphone, the microphone of FritzFons my own voice takes in an echo and then I hear myself twice. Here there should be a possibility that you can reduce the sensitivity of the microphone slightly.

So a strong buy recommendation for the FritzFon, but only for people who have already a digital VoIP connection.