We use in addition to the MD-F now two M2 phones at a Fritz box. With M2 we have not found any problems. Neither in speakerphone, yet charging the battery they occur, in part, as described here on. Only the lighting is not uniform, as already mentioned. This was not buying decisive for us. It is striking that in our opinion the better M2 / comfortable in the hand as the MD-F, is probably connected with the design. We do not regret buying, especially the three phones are hervoragend to handle together. Radio problems do not occur, although it is on two floors on the phone / connected. So therefore from us 5 stars.