I was disappointed to find that both phones can't be used at the same time as with a real extension. So both you and the wife can't be on the phone at the same time talking to Dad - one has to hang up for the other to get on. Also, they seem to lose their ability to recognize the system, and have to be re- set - a simple process but annoying to have to do more than once. And they are cheaply constructed. But they work - so I guess I can't really complain too much considering the price.