These systems can make all the lights in your house flash or dim whenever the doorbell rings. They are particularly useful if you need to know your doorbell is ringing wherever you are in the house. These systems depend on how your home is wired, for example, if you have two lighting circuits, one for upstairs and one for downstairs, you connect the system to one circuit and therefore light up only one floor. During the day you must leave the light switched on in any room where you need the signal. The lights in those rooms will then come on when the doorbell switch is pressed.
Some systems have an additional connection for a second doorbell switch.
It is also possible to connect an audible bell to the system if you want. One advantage of this type of system is that wires do not have to run to all your rooms - the system only needs a small amount of mains wiring at the fuse box. A qualified electrician must install this system. Doorphones or entryphones These devices alert you to a door entry system or intercom buzzer by automatically flashing or dimming the house lights. If you cannot install a wired visual system or doorbell for technical reasons, for example, if you live in a block of flats that has a doorphone or entryphone, these systems may be the answer.