A:Answer Not sure about your question. Install was to plug the phone line or lines into the main base unit. The satellite units are simply plugged into an ac outlet. The instructions are not clear on this, but you need to register each handset by putting it into the main base unit and doing the registration process which is fairly simple. It does not work if you put each handset in its own base unit. Also, charge everything overnight before you set it up. I have had the system for about a month and my only "complaint" is that I wish it had more ring tones to choose from.