If your home or small business uses the Panasonic 8 x 24 Phone System or Small Business 8 x 48 Panasonic Phone System, you can add security and reduce time spent running to answer the door with the Panasonic Premium Doorphone. When its call button is pressed, this door intercom system will ring the doorbell as well as all the phones in the house with a distinctive ring. Answer any phone to have a two-way intercom conversation with your visitor. The Panasonic Premium Doorphone is an accessory to a Panasonic phone system, which is required and sold separately.Use 22- to 26-gauge wire between the intercom station and the phone system. Ideal for homes or businesses spread over larger areas, the Panasonic Premium Doorphone offers twice the wiring distance of the standard intercom doorphone. The Panasonic Premium Doorphone intercom comes with a black mounting plate. You can upgrade this faceplate with the Brushed Stainless Faceplate or the Polished Brass Faceplate.