How an intercom works: the principle of operation depending on the type - Setafi

Understanding how the intercom works is quite simple. When the key is applied from the outside, the electromagnetic field blocking the door stops for a short time. A similar situation is observed when pressing the button inside the apartment. The principle of operation is the same, but the types of devices are different. Each type is described in detail in the presented article.

Principle of operation

Regardless of the specific type, the principle of intercom operation is general. The device consists of several elements:

1. Call panel - installed on the entrance door or behind the gate. It consists of a reader, the actual panel with buttons, equipped with a microphone and a speaker. If video transmission is provided, a small camera is also installed on the panel.
2. Tube - installed in the apartment. Usually it has 2 buttons - on / off and to open the door. If the intercom device involves video communication, it is equipped with a monitor.
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3. An electronic key-identifier is a device with a personal access code. It is read using a key fob (key) and a magnetic card; modern models also provide for the use of biometric data.
4. Electric or electromechanical lock. The first is more durable, but there is a risk that the door will not open if the electricity goes out. Therefore, it is better to choose the second option.
5. Cable for connecting all elements (some types of intercoms require communication via a local Internet or Wi-Fi network).
6. The door closer for the intercom door is a typical device with hydraulics that performs soft closing. Works in any weather, without freezing, thanks to the filling of special oil.
7. Also, intercoms are equipped with auxiliary components - brackets for installation, visors that protect against atmospheric precipitation, a power supply unit and a switch.

Types of intercoms

When choosing a suitable device, you need to figure out how the intercom works, as well as what types it comes in. The main classification criteria are related to the type of signal, the number of subscribers and other parameters.

Signal type

For the consumer, this is the most important feature. An intercom device in an apartment building usually involves only audio communication with someone who is trying to enter the entrance. But there are also models equipped with a video camera. Thus, according to the type of signal, the models are divided into 2 types:

1. Audio intercoms are the most common option due to the affordable cost of installation and maintenance.
2. Video intercoms - equipped with a camera at the entrance and a monitor in the house. Thanks to this, the guest can not only be heard, but also seen. Such models are more expensive, so they are less common.

Signal transmission technology

What the intercom consists of and how it functions depends on the type of signal transmission:

1. Analog - it is transmitted, as in a regular phone, via cable. To do this, they install a small analog switch, which serves as an analogue of a PBX, as well as a multi-core cable leading to each specific apartment.
2. Digital – Only 2 cables can be used, with each user being unmistakably identified using a coding system.

There are also wireless systems in which the signal is transmitted over an Internet cable (it installed separately) or Wi-Fi. These are modern devices that are usually mounted in small houses.

According to the presence of the tube

There are 2 types of models:

• with a tube - the traditional option;
• without a tube ("hands free").

The principle of operation of the intercom at the entrance is the same, but it differs in terms of the presence or absence of a tube. Most often, it is - when a call is received, the handset is removed and through it they communicate with the visitor, as if by telephone.

This is a simple budget option that is most common. But there is also an intercom system without a tube. It provides silence and has a stylish design. It is a panel with a speaker through which you can talk to the guest.

By number of subscribers

According to this criterion, the models are divided into 2 types:

1. Individual.
2. Multi-subscriber.

The first ones are installed in private houses, as well as in cottages or in 2-3-story houses. They can serve within 10-20 users. In urban skyscrapers, a multi-subscriber caller is used, designed for several tens or even hundreds of users.

Type of castle

Finally, there is a classification depending on the type of lock:

1. Electric (electromagnetic, magnetic).
2. Electromechanical.

In the first case, the door is blocked by a mechanical unit, which is controlled by an electric drive. In the second case, the door is completely operated by an electromagnetic field, which stops when the key is applied. It is quite obvious why an intercom is needed - it performs the function of not only transmitting a signal, but also opening / closing the door.

It is clear how the video intercom call panel works. It allows you to get into the apartment both with the help of an electromagnetic key from the outside, and by pressing a button inside the apartment itself. In terms of price, it is easier to install a typical audio intercom. But in terms of practicality, it is better to purchase a model with a video camera. At the same time, you need to pay attention to the quality of the shooting and the reliability of the case so that the outdoor part of the mechanism can work in any weather.