On occasion, while speaking with a relative in Georgia who also has an iPhone, we will both hear what sounds like somebody dialing a phone number on a telephone keypad. The tones are loud enough that they have caused us to end calls. The keyboard sounds are heard on both ends of the call and on occasion, it sounds like a key is being held down, creating a long duration tone. This does not happen on every call, but the frequency has been increasing recently. It does not happen for me (or my relative as far as I know) on any calls other than calls to my family member.