When a visitor presses the button on the door intercom, the DoorBell Fon rings the phones in your home with a distinctive ring. Pick up the phone to converse with the door. If you are on the phone when a visitor arrives a call waiting tone will sound to alert you. In fact, the DoorBell Fon system will even work without phone service. The system provides the necessary voltage to operate on its own. Up to 2 intercom stations can be attached. Add an optional Electric Lock Controller, electric door strike, a corresponding power supply and you can unlock the door from the phone by pressing "*". Easy 2 wire connection to door intercoms. Works with answering machines, most home PBX phone systems, and phone-company provided services like voice mail. Includes one door intercom station, which measures 3 7/8" X 5 1/8" X 1", and a power supply. This system is also available in Brass, Aluminum, and Ivory. Expand your intercom system with these optional accessories: Electric Lock Controller (#5070EL) Add this optional lock controller and an electric door strike and power supply and you can unlock the door from the phone by pressing "*". We recommend the following doorstrikes: Electric Doorstrike 8-16VAC (#5190) 16VAC Electric Doorstrike for Schlage Locks (#5190S) 12VDC Electric Doorstrike for Schlage Locks (#5190S12) A seperate power supply is required when using a doorstrike. See the doorstrike page for a recommended power supply. Doorchime Interface Module (#5070CI) Provides 800ms of dry contact contact closure, and is simply bridged to the door box leads. Activated by the push button on the door box, it's perfect for integrating a door chime, activating a camera, or turning on a light with your DoorBell Fon system. Requires two AA batteries, included. Ring Extender (#5070R) Increases the number of rings the DoorBell Fon will provide from three to eight. Normally, after someone presses the button on the outdoor intercom station, the phone will ring and there be approximately 20 seconds available for you to pick up the telephone and be automatically connected to the doorbox. By installing this chip, you'll have a total of 8 rings or about one minute. Extra Ivory Intercom (#5070DS) For applications where you have multiple entryways, purchase an additional intercom. Also available in White, Brass, and Aluminum. Doorbell Fon Intercom Module (#5070IM) The Doorbell Fon Intercom Module allows you to pick up any phone in the house and trigger all of the other phones to ring. The distinctive ring will indicate to others in the house that this is an intercom call, not a telephone or door box call. Intercom Awning Single Gang (#5070A) If your intercom is not located under an awning, we recommend that you purchase this awning specifically designed to protect the intercom against direct rain and snow.