According to some very bad reviews I have halfway unsettled ordered me the phone, since the Siemens Gigaset models are probably limited to compatible Fitzbox. I have not looked back. My Fritz box, as well as the phone, the newest laboratory firmware, which optimizes the phone. Everything works fine and the sound quality is excellent, depending on the interlocutor hear significantly better than conventional. I call on VoIP with cable Germany (32 Mbit / s). The often-mentioned disorders can come here with VoIP also by the provider used. Even the look of the phone to me like good, it looks high. In conclusion I must say that some of the reviews submitted but are quite unqualified and does not really help the reader seeking advice. I would not hesitate to recommend the phone in my constellation for sale.