Audio and video intercoms

Recommendation points

• Audio intercoms
• Video intercoms
• Features of the installation and operation of intercoms

The issues of property security, restricting the access of unauthorized persons to certain objects (premises, buildings, territory) have always been relevant. Security, combination locks, concierges at the entrance to the entrances of houses – these are the very measures that are aimed at restricting the access of unauthorized persons. Some kind of modern access control systems (intercoms) appeared in the United States in the first half of the 50s of the last century. Progress does not stand still and instead of people, smart devices have long been used. So in the early 60s, these devices began to appear in the USSR. This product bore the name “MOSLIFT system” and was extremely bulky, short-lived and inconvenient in everyday use. Naturally, the first copies were installed in the capital..

Initially, these devices were not in great demand. But in the “troubled” times of perestroika, people began to massively install combination locks and intercoms at the entrances of their houses. The first intercoms were pretty primitive. Their production was established in Asia (China, Korea). Soviet products were also installed, but they were largely inferior in design to imported ones. In the first intercoms, it was not possible to conduct a conversation simultaneously with the guest and the owner of the room (simplex communication), there was no video image, etc. There were many problems with the workmanship and durability of the outer part of the intercoms.

In the modern world, access restriction systems (in this case, intercoms) are increasingly in demand. We often encounter such devices in the modern high-tech world and at the same time do not even think that such a simple system as an audio intercom (video intercom) can be an integral part of the automation of the entire facility.

Audio intercoms

Let’s look at one of the simplest access restriction systems – an audio intercom. This system is a simple intercom (duplex communication – two people can speak at the same time), which is additionally equipped with a remote control device for the door locking mechanism (magnetic lock, electromechanical lock). This system is most widely used in apartment buildings. There are single-channel and multi-channel systems (designed for one subscriber or for several).

There are several options for opening the lock in this system. You can dial a special numeric code, use a regular key, use a special chip key (Touch Memory or iButton – a special magnetic key was developed by the specialists of the American corporation Dallas Semiconductors in the early 90s), open remotely from an apartment. It all depends on the cost of the installed access system. Most systems open doors with a chip key. This key looks like a battery; a special 48-bit chip is located inside the metal case. This key is resistant to mechanical stress, it is almost impossible to counterfeit. The outer part of the intercom is a panel in the so-called “vandal-proof” design (resistant to all kinds of mechanical stress). The panel contains a keyboard, an intercom and contacts for a chip key. From the very name of the system (single-channel or multi-channel) it follows that the intercom is intended either for individual or collective use (for example, in apartment buildings). The interior of the intercom is made in the form of a handset with a lock control key and a signal volume control button. Installation of such systems is quite simple, they are convenient to use and durable..

Video intercoms

The new generation of video intercoms allows you not only to negotiate with the visitor, but also gives you the opportunity to see him, watch what is happening in the front door area, record what is happening on the computer. These are more expensive devices in comparison with audio intercoms. Naturally, not all video doorphones have similar functions. In everyday life, you can most often find video intercoms, which are similar to multifunctional office phones, only without a keyboard, but with a large screen. Modern models of video intercoms are equipped with color screens.

An external intercom is not much different from an audio intercom intercom. Some people mount a surveillance camera separately from the intercom in order to increase the viewing angle of the territory. Many video intercoms have the ability to display the image on the TV screen. Video intercoms are also single-channel and multi-channel, the installation of these devices (audio and video intercoms) is exactly the same.

Features of the installation and operation of intercoms

We will not talk for a long time about the features of the installation of multichannel audio and video intercoms, since specialized enterprises are most often engaged in the installation, adjustment and maintenance of such devices. But there are also some peculiarities here that are worth knowing about. Some firms use unfair competition methods. They offer the same access systems at lower prices, but they are silent about the configuration of such a system. For example. Not everyone knows that magnetic locks are designed for different loads. Some do an excellent job with a load of 500 kg. others can be opened by applying a force of about 250 kg. They also save on installing an emergency power supply. At the time of a power outage, such an access system is simply turned off and does not perform its functions.

Installation of single-channel intercoms is extremely simple and many users are able to make it on their own with some skills. Most often, the kit includes everything you need to install an intercom in an apartment, from the device itself to the fasteners. If you are installing an intercom in a private house and the distance between the blocks is large enough, then you will have to additionally purchase wires for installing the intercom. If everything is quite simple with the audio intercom, then when installing the video intercom, you need to take into account the location of the outdoor video camera, you need to first check whether all objects fall into the field of view. In addition, the distance between the blocks is rather limited, since this directly affects the quality of the video signal. It is enough just to mount wireless intercoms. You don’t need to lay wires, drill walls.

But do not forget that various factors can affect the quality of the radio signal, ranging from weather conditions to the reinforced concrete walls of your house, metal doors, and various electrical interference that household appliances create. Not all models of video intercoms allow connecting additional cameras. This significantly limits the scope of application of such devices. It is also worth remembering that the video intercom registers the image in the form of separate frames (like a photograph), and not the dynamic image itself. The capacity (memory) of the video intercom is also different. This should be taken into account when choosing a particular model, since not all models allow increasing the amount of memory and new images will be recorded instead of old images. Not all models of video intercoms with recorders have built-in emergency power supply. This can lead to the fact that at the moment of a power outage, all the accumulated video information will be simply erased from the memory of your intercom.

The most common door closer plays a huge role in ensuring the operability of the intercom. The door closer must not only be correctly selected (each door closer is designed for a certain door weight), but also correctly installed and adjusted. Otherwise, your door will simply remain open or it will rattle strongly at the moment of closing.

Pay attention to the lock with which you are going to equip your door. If an electromechanical lock is simple enough to select and install, then not every consumer can install a magnetic lock on his own. There are some features that only those people who professionally install such products know. For example. Not everyone knows that there are certain requirements for a door handle located on a door with a magnetic lock. The force that the door handle can withstand should not exceed the force that the magnetic lock can withstand. In other words, if your magnetic lock is capable of withstanding a force of 500 kg, then you should not ask to “tightly” weld the handle to a metal door. The door should be easy to open with one hand and the handle should be designed for only one hand. We have already mentioned the emergency power supply that will provide the intercom with electricity during outages. It is worth recalling that the operating time of such emergency sources also has its limits. Not all systems are equipped with an automatic battery charger, which can cause additional inconvenience during operation due to the need to control the voltage in the batteries..

It is simply impossible to know all the subtleties of choosing, installing and maintaining intercoms without being a specialist in this field. For this reason, you should not refuse the services of enterprises that sell and service such access systems. We hope that this information will be useful to you and you have learned more about intercoms.