You will need
  • permission of residents
The choice of intercom is determined by whether it is installed in private or apartment house, as all the intercoms are divided into malabarensis and multi apartment. Namely multi apartment intercoms are suitable for installation in apartment buildings. All intercoms are also divided into two large classes: audiointercoms and videointercoms. Videodoor phones come in with color and black-and-white displays. When choosing the video intercom you need to consider that his purchase will cost you much more than buying a door phone.
When you select Videophone remember that camcorder with wide angle of view allows you to see the amount of space that a camera with a lower angle will show larger face of the visitor. For some equipment it is possible to connect two cameras to expand the viewing area or to install cameras in different places. Camera most intercoms are equipped with a backlight. Color cameras have an led light, and black-and-white camera equipped with infrared illumination. This allows even in complete darkness to see the face of the visitor. However, in some cases, the intercom will not efficiently perform its functions, for example, in bright sunlight, aimed at the camera.
Passing the entrances are now quite rare, but we cannot ignore their existence. If tenants want this entrance to admit guests via both inputs, it is better to choose the intercom that allows you to connect two call block and two cameras. On the market now presented intercoms with the ability to connect up to six devices (call blocks, video cameras, and additional handsets). However, security experts recommend one of the doors of walk-through entrances equipped not with the intercom and a lock with keys.
Currently, the market is coordinate and digital intercoms. The cost of the first lower due to the cheaper tubes, but less reliable. Digital intercoms safer and easier to install, but have a higher price.
The choice of intercom system that has an embedded power supply will save you from extra hassle. This power supply can connect electric lock of the front door. Or get ready for what you have to keep the apartment another wire and put the power supply, which required additional socket. By the way, Electromechanical locks (like deadbolts) safer than electromagnetic.
The intercoms are divided in duplex and simplex. Duplex intercoms communicate in two directions simultaneously, and simplex intercoms allow you to speak only in turn. Typically, full-duplex intercoms in apartments equipped with a tube resembling a phone and the simplex represent a device with a speakerphone. When you select the intercom consider whether you are comfortable to talk on speakerphone, or you are more comfortable negotiating through a tube.
Special attention to call the panel. They are recessed and overhead. The call blocks intercoms can be made of plastic and metal. And since in our country, the respect to private and public property is still not up to par, you need to ensure that the call block, located on the street, was protected from vandals. It is better to choose a door with a milled or cast call block and with metal buttons-balanced type.
If you are going to connect the multi apartment intercom is an internal communication between the residents of the entrance, communication with the Manager or Concierge. Modern intercoms can also serve as an alarm button. If you want to know who came in your absence, will help the selection of video intercom system with photo opportunity to visitors, saving the images in a special memory block, and their subsequent viewing. In some models you can connect a second handset (intercom) that is not equipped with a display, but allows you to communicate with the visitor and open the door for him. Of course, any additional features will influence the cost of the intercom.