Door Phones: specifications, types

General type of calling panel.

Classic calling panels nowadays are divided into audio and video devices. In addition, you can find such a specific variety on sale as Wi-Fi video calls. Here is a detailed description of each of these options:

- Audio. Call panels that support voice communication, but do not have cameras and do not provide video transmission. Accordingly, the functionality of such models is noticeably limited compared to video panels. On the other hand, video transmission is not always an important issue: for example, in some situations a guest can be seen without a built-in camera (through a glass door, using separate surveillance cameras, etc.). And the security issue is not always so serious that visual confirmation is required for everyone who comes. At the same time, audio panels are noticeably cheaper than models with video and have less stringent requirements for other system components - in particular, the intercom with which such a panel is used may not have a screen at all.

- Video. Calling panels with built-in cameras capable of transmitting to the intercom not only the voice of the person who has arrived, but also his image. This is the most functional and practical option from a security point of view, however, it is quite expensive - both because of the price of the panels thems...elves and because of the requirements for other equipment (for example, the intercom must have a screen - otherwise video support loses all meaning).

- Video call. A simplified and “lightweight” analogue of a calling panel: a doorbell with a built-in camera and a Wi-Fi module. Such devices differ from video panels in two key ways. First of all, they do not provide the ability to control a magnetic lock - in other words, you cannot open the door remotely via a video call. On the other hand, a video call does not require an intercom or other special equipment - video and audio from such a device is transmitted via Wi-Fi to a smartphone, tablet or computer with a special application installed. Thus, video calls are as simple as possible to install and configure. Note that the specific capabilities of such devices may vary: for example, some of them only send a signal to the connected gadget, others are equipped with an internal unit with a speaker and can be used in the same way as regular doorbells. And some models can even work via the Internet, which allows you to communicate with the visitor without being on site.

— Street (universal). Call panels that can be used outdoors. Even in a fairly mild climate, "street" devices are constantly exposed to various adverse effects: precipitation, temperature changes, ultraviolet radiation; in addition, they can be a very attractive target for hooligans and vandals. All this requires the use of durable and sustainable materials. At the same time, nothing prevents the installation of such panels in the premises (hence the name "universal").

— Premises. Call panels designed for installation inside buildings. Such placement assumes quite favorable conditions (lack of moisture, almost constant temperature, etc.), as well as a minimal risk of vandalism. Therefore, "internal" devices do not have such a margin of safety and reliability as external ones; this has a positive effect on the cost, but does not allow the use of outdoor panels of this type outdoors.

Call panel installation method.

— Mounted. Installation by hanging from fixtures placed on a wall, door frame, or other suitable location. This method is quite simple, besides, it allows you to relatively easily change the location of the device. On the other hand, it is less reliable than embedding, and it is easier for hooligans or thieves to rip such a panel from its attachment point.

— Embedded. Installation in a niche in a wall or other surface — in such a way that only the front side of the device is outside. and any movement of the device is also fraught with serious difficulties. Nevertheless, it also has advantages: it is almost impossible to remove the call panel from a niche without a special tool, and even with tools, this task takes time and effort.

— Mounted / built-in. This category includes outdoor panels that allow both of the installation options described above. Thus, the user can independently choose a method, depending on what is more important in this case: ease of installation or its reliability.

The number of subscribers that can be simultaneously connected to the calling panel. Please note that in our catalog this parameter is indicated only for the so-called. low-subscription models ( for 1 subscriber, for 2 subscribers, for 3 subscribers, for 4 subscribers, etc.), in which each subscriber is allocated its own call button (as a rule, such buttons can be signed), and their total number is usually does not exceed 10 (optimal for townhouses). If the calling panel has a numeric keypad and is intended for apartment buildings, it is considered multi-subscriber, and in this case the maximum number of subscribers depends on the internal device (in any case, it is at least several dozen).

Type of multi-user outdoor panel — that is, a model designed for use in systems with numerous subscribers (on the order of several tens or even hundreds), for example, in residential apartment buildings. Such devices necessarily have numeric keypads — they are easier and cheaper than a separate call button for each apartment. The type of control used in such keyboards determines in this case the general type of the panel:

— Button. Devices with traditional mechanical buttons. They are cheaper than touch ones, besides, the buttons are more convenient when dialing by touch — they protrude more above the surface and are not so prone to accidental operation. Another advantage of the buttons is that they can be pressed while wearing gloves (whereas the sensor may not work); on the other hand, pressing itself requires a certain effort.

— Touch. Sensors give the panel an elegant and advanced appearance, while they are quite vandal resistant — it is almost impossible to break the sensor, unlike the button. In addition, such keyboards are more reliable and durable, because. have no moving parts that are prone to wear. Their main disadvantages are high cost and (in most cases) inability to respond to a gloved hand, which can be uncomfortable in cold weather.

A method for connecting the calling panel to an intercom or other similar device.

All modern connection types can be divided into three main categories: wired analog(2, 3 or 4 wires), wired digital(network - LAN) and wireless(Wi-Fi). Moreover, the last two formats can be combined in one device. Here is a more detailed description of each of these options:

— 2-wire. The simplest type of wired analog connection; used in select low-cost audio panels (see "Type").

— 3-wire. A very rare option: in simple analog devices, manufacturers often provide 2 wires, and in advanced ones - 4.

— 4-wire. The most functional and, as a result, the most popular type of analog wired connection. Suitable even for high-end video panels, although in fact it is found in all categories of devices - from budget to high-end.

— RJ-45. Connection via an RJ-45 connector via an Ethernet network cable (“twisted pair”). This option is convenient because the calling panel can be connected to a local computer network, which provides several advantages. Firstly, the ability to access the panel can be configured on any computer or gadget within the network. Secondly, many similar models can work without intercoms and other special equipment - through an application on a computer/gadget. Thirdly, laying a network cable from the panel to the router/switch i...s often simpler than organizing an analog connection (for example, 4 wires - see above). Fourthly, the number of panels and other special equipment within the local area can be almost any - it is quite possible to combine, for example, all the calling panels of an apartment building or a large office center into one network. And if you wish, you can even set up access to the calling panel via the Internet, which will make it possible to communicate with visitors and control access to the premises, even when you are not on site.

- Wi-Fi. Connection via Wi-Fi wireless standard. This option provides almost all the same capabilities as the RJ-45 described above, but has certain differences. The most noticeable of them is the absence of a wire, which greatly simplifies installation and connection. At the same time, even relatively limited Wi-Fi devices have the power to operate reliably at a distance of a couple of tens of meters or through 1 - 2 medium-thick walls. The second nuance is the possibility of direct communication with a smartphone, tablet, etc., without using computer networks; This possibility should be clarified separately, but it is in this format, for example, that video calls work (see “Type”).

— RJ-45 / Wi-Fi. Supports the two connection methods described above at once. Such panels turn out to be as universal as possible, however, in practice, the ability to freely choose between LAN and Wi-Fi is extremely rarely required, and it significantly affects the cost. Therefore, this option was not particularly widespread.

— Motion detection. A sensor that allows the calling panel with a camera to respond to movement in the camera’s field of view. The specific reaction method may be different, depending on the model and settings of the entire system: turning on recording or broadcasting to an external device, sending a notification to the customer, sending a signal to the alarm output (see below), etc.

- Mobile app. This feature means that you can work with the calling panel via a smartphone or tablet with a special application installed on it. Such applications are usually released immediately for both of the most popular mobile operating systems today - Android and iOS; however, it would not hurt to clarify this point separately. In any case, control from a mobile device can have very extensive functionality (including even the ability to work via the Internet, in some models); and interacting with the panel through a gadget that you can always keep with you is definitely more convenient than every time going to the intercom or other stationary equipment.

— Face recognition. The facial recognition function is one of the types of biometric access systems. It is based on a digital camera, often complemented by a built-in backlight for identifying faces in the dark. Initially, such devices were not very accurate: they could be confused by changes in facial hair or makeup,...the appearance or disappearance of glasses, and some models could be deceived using photography. With rare exceptions, facial recognition today uses advanced algorithms and high-end cameras with 3D scanners that read a three-dimensional model of the face. The device stores the customer library in its memory. The function is found in flagship calling panels.

— SIP protocol. The device supports the SIP protocol. This is a standard originally created for Internet telephony - the transmission of information (audio, video, special data) over telephone networks in digital format using the IP protocol (the same one on which the Internet is built). Internet telephony is quite popular nowadays, especially in business: it allows you to establish effective interaction between individual departments of a company, even tech located in different countries. Accordingly, if the building already uses equipment for Internet telephony, then SIP support can significantly facilitate the integration of the calling panel into the overall security system.

— Reading contactless keys. The presence in the design of the intercom calling panel of a module for reading data from contactless keys. They can be in the form of smart cards, key fobs or other devices that contain a microchip with a unique identifier. When the customer brings the key to the reader, the system identifies it, checks it against the database and allows access if there is a match. Note that the intercom calling panel can record not only the response time, but also the identifiers themselves - this provides advanced capabilities for access control and visitor registration.

— Alarm input/output. As a rule, calling panels with this function are equipped with both inputs and outputs; the number of both may be more than one. In general, these connectors are used to transmit control signals between different ones within a security system; they allow you to build a very advanced system and provide additional capabilities for managing its functions. At the same time, we note that the alarm input or output is not necessarily responsible for triggering the alarm - it all depends on the specific settings. For example, a signal from such an input can serve as a command to turn on the “night” IR illumination or start recording video from surveillance cameras.

— Display. Its own screen, installed directly on the calling panel, allows you to display various additional information useful for the visitor. The specific functionality of such a screen can be different - from a simple indicator that can show only numbers (for example, the number of a called apartment or office) to a full-color display suitable for two-way video communication. However, in any case, this feature increases the convenience and clarity of using the calling panel.

— Night shooting (IR illumination). The presence of an infrared illumination function in the camera video panel (see “Type”), which allows you to obtain a visible image in the dark and even in complete darkness. IR illumination is not visible to the human eye, but is well perceived by the sensors of modern digital cameras. True, the image in this mode can only be black and white, but in most cases this is not any significant drawback.

— LED backlight. The camera video panel (see “Type”) has LED backlighting. Like the infrared illumination described above, this backlight is designed to work in the dark; however, it provides light that is visible to the human eye. The latter, on the one hand, allows the camera to produce a relatively natural color image, on the other hand, it can create inconvenience for the guest due to the bright light in the eyes.

— Illuminated buttons. The design of the calling panel includes backlit buttons. The function allows you to see the keyboard normally even in low light conditions - in the evening, at night, in cloudy weather, when placing the panel in a dark place, etc. Note that the backlight usually covers other significant elements of the panel - for example, the location of the sensor for a smart card or key.

A card reader is a device for working with removable memory cards. Such media are used to record data, which allows you to save events occurring in front of the calling panel at the right time.

The type of camera installed in the video panel (see "Type").

— Coloured. Cameras capable of displaying images in colour (not just grayscale like black and white). Such an image is more in line with the real situation, and some find it even more pleasant. At the same time, do not forget that to view it you will need a colour screen on the intercom itself — otherwise all the advantages of such cameras will be irrelevant.

— Monochrome. A camera that provides a black and white image. This image is not as reliable as colour, but for most cases it is enough. In addition, such cameras are cheaper — not only due to their own low cost, but also due to the fact that they allow the use of intercoms with inexpensive black and white displays.

Type of matrix installed in the camera of the video panel (see "Type").

— CMOS. She is CMOP. Relatively inexpensive matrices, which, nevertheless, provide good image processing speed with low power consumption, and also take up little space (which is very important for miniature cameras). Their main disadvantage is the increased tendency to the appearance of noise in the image, which is why the quality of this image is somewhat inferior to CMOS CCD.

— CCD. The Russian equivalent of the name is "PZS". Such sensors are somewhat more expensive than CMOS, due to the complexity of the design, and their size is somewhat larger. At the same time, they have more uniform characteristics and are not as prone to heat during operation, which reduces noise and has a positive effect on image quality — especially with a small amount of light.

Diagonal size of the surveillance camera matrix. This parameter is traditionally indicated in inches and fractions of an inch.

With the same type (see above) and the number of megapixels (see below), larger sensors are considered more advanced. This is due to the fact that a large sensor size means a larger area of each individual pixel — and this, in turn, increases the amount of light falling on each pixel, has a positive effect on light sensitivity and reduces noise. Large sensors are especially important for working in low light conditions, including with IR illumination (see "Design and capabilities"). However, for calling panels, matrices are mainly limited to 1/4" and 1/3" sizes. Other options are much less common.

The number of megapixels in the camera sensor, in other words, its resolution. A megapixel is one million light-sensitive dots (pixels) that make up an image; the resolution of modern matrices is very high, so it is more convenient to use just this method of designation. However, for call panels, the values are 1 MP, 1.3 MP and 2 MP. More advanced options are extremely rare.

The higher the resolution of the matrix, the higher the video resolution can be (see below), the more detailed the image can be provided by the door panel camera. At the same time, note that as the number of megapixels increases (without changing the size of the matrix), the size of each individual pixel decreases, which increases the likelihood of noise and deterioration in the overall image quality. Therefore, high resolution in itself is not necessarily a sign of high quality — a lot depends on other things, for example, on the size of the matrix (see above).

The maximum video resolution that the call panel camera can provide.

The higher the resolution of the video, the more details you can see on it, the less details will be blurry. On the other hand, high resolution means large volumes of video materials, which, accordingly, requires fast communication channels, and this indicator significantly affects the cost of the device.

Resolution of the image produced by the camera of the video panel (see "Type"). In such cameras, an analogue signal transmission format is used, and for it the resolution is usually indicated not in pixels horizontally and vertically, but in TVL — TV lines. This is due to the fact that the image in the analogue PAL and NTSC colour systems always has the same vertical size — 625 lines. Therefore, to indicate the differences between "pictures" of different resolutions, it is enough to know the horizontal size — i.e. number of lines.

In fact, this parameter describes the quality of the image that is displayed directly on the screen connected to the camera. The higher the resolution in TVL, the more detailed the image will be produced by the camera; this is especially important for models with wide viewing angles (see below). On the other hand, in order to use all the features of a camera with numerous TV lines, a screen corresponding to these features is also required; For more details on compatibility with the screen, see specialized sources.

Video compression format (codec) used by the door panel camera.

In practice, this information is important mainly for assessing compatibility with other special equipment, as well as when viewing captured video on household media players. This point is not important for interaction with a computer: most modern operating systems have extensive sets of built-in codecs, and if necessary, additional codecs can be installed separately. However, different video compression formats also have some specific features, here they are:

- H.263. The oldest of the codecs widely used in digital cameras of calling panels. It was created back in the mid-1990s for efficient video transmission over low-bandwidth channels; nowadays it is considered obsolete and is found extremely rarely in calling panels, and exclusively as an addition to the more advanced H.264 (see below).

- H.264. A codec widely used in modern video equipment, including for transmitting high-definition video. It provides a good compression ratio while maintaining quality, and is not particularly demanding on computing power, which is why it is extremely popular in our time.

- H.265. The newest and most advanced of the formats found in calling panels. It provides even higher efficiency than H.264, supports resolutions up to 8K, but has quite serious hardware requirements. As a result, support for this standard is...rarely found in calling panels.

Horizontal size of the video panel covered by the camera (see "Type"); this size is most conveniently indicated by the angle between the lines connecting the camera lens with the left and right edges of the scene being viewed.

Theoretically, the wider the viewing angle, the more space the camera is able to cover and the less likely it is that some details will remain out of the frame. At the same time, taking into account the specifics of the use of outdoor panels, it is usually not necessary to equip them with wide-angle cameras; moreover, such optics would be inconvenient due to distortion and reduction effect. Therefore, most models have horizontal viewing angles in the range of 60 – 80 ° — this is quite enough for the intended use.

The vertical size of the video panel covered by the camera (see "Type"), in other words, the angle between two lines connecting the lens with the top and bottom edges of the scene being viewed. The value of the viewing angles is described in detail above in paragraph "Viewing angles horizontally"; we only note that they are usually smaller vertically than horizontally, and in many models this parameter is not indicated at all because of its secondary importance.

This value characterizes the angle of coverage of the image diagonally, this figure is usually slightly larger than the horizontal angle, this is due to the fact that the frame that we see is already in a rectangular form, usually with an aspect ratio of 3 to 4 or 16 to 9, and part of the frame can be circumcised. This indicator, along with the horizontal and vertical viewing angles, allows you to estimate from what distance the visibility of the interlocutor will be acceptable.

The lowest level of illumination of the observed area, at which the camera of the video panel (see "Type") is able to "consider" the surrounding objects without additional illumination. This parameter is expressed in lux, and thanks to special tables it is possible to estimate what actual level of illumination corresponds to a particular value (for example, 0.01 lux — a clear night with a quarter of the moon, etc.).

The lower this value, the generally better the camera is for low light conditions and the darker the environment in which it can be used without backlight.

The focal length is such a distance from the lens to the matrix, at which a clear image is obtained on the matrix (when the lens is focused to infinity). The viewing angles of the lens primarily depend on this indicator (see above): the smaller it is, the wider the viewing angles and the smaller the objects in the frame (and vice versa). At the same time, it should be noted that the actual viewing angle is determined not only by the focal length, but also by the size of the matrix (see above). In fact, this means that with different sizes of matrices, lenses with the same focal length will have different working angles.

— WDR. WDR technology (Wide Dynamic Range, extended dynamic range) combines several frames with different exposures into one picture, as a result, dark areas are brightened, and overexposures are darkened, and the output is a picture with extremely uniform lighting. The true wide dynamic range technology is called True-WDR and it is implemented in the optical circuit at the hardware level, a special microprocessor is responsible for creating and mixing exposures. A more affordable alternative to wide dynamic range is Digital-WDR technology, which equalizes lighting through software algorithms.

— DWDR. DWDR (Digital Wide Dynamic Range) technology brightens too dark areas of the frame, which can be completely blurred against the background of light areas. Digital brightening allows you to noticeably improve the quality of shooting in contrasting lighting conditions. Digital WDR cameras are noticeably cheaper than true True-WDR optics. Of course, the quality of digital brightening is inferior to True-WDR.

— BLC (Back Light Compensation) — backlight compensation technology. This system is based on the work of digital signal processors DSP. So, the device, relatively speaking, "breaks" the frame into many segments, making its own adjustments to each of them. Backlight compensation brightens dark areas of the frame well. The main disadvantage of the technology is the increase in the brightness of the already bright ar...eas of the frame, due to which overexposure may appear in the picture.

— WDR+BLC. Call panels with a camera that supports several lighting technologies at once, each of which is described in more detail above. Immediately, we note that the combination of WDR + BLC allows you to achieve an extremely clear and clear picture in almost any lighting conditions, from extreme contrast to insufficient and excessively bright.

Possibility to rotate the lens of the camera installed in the video panel (see "Type"). This function is useful when installing the device in non-standard conditions, where the direct location of the camera would be inconvenient: by turning the "peephole", you can optimally adjust the frame. Note that the rotation is carried out when the panel is installed, after which the camera, usually, remains motionless.

Call panel support POE (Power Over Ethernet). This feature is only found on models with LAN connection. As the name suggests, it allows power to be supplied through the same network cable that connects the device to an intercom or other device. This is much more convenient than laying a separate wire for power or fiddling with autonomous power sources.

The amount of energy consumed by the call panel.

Devices that do not need to be connected to a power source. In the case of the call itself, it is possible to install batteries, which will supply the gadget with the charge necessary for operation. This solution simplifies installation as it does not need to run a power cable.

This protection describes how well the case protects sensitive internal components from dust and moisture. By default, it is denoted by the letters IP followed by two numbers — IP44, IP54, IP55, IP65, IP66, etc. The first digit means protection against the ingress of solid objects and dust, and the following levels of protection correspond to its individual values:

4 — protection against objects with a diameter of more than 1 mm
5 — dustproof (full protection against contact; dust can penetrate inside, but does not affect the operation of the device)
6 — dust tight (enclosure with full protection against dust and contact). br> Smaller values do not occur and there is no point in specifying them.

The second digit characterizes the protection against moisture, here the values \u200b\u200bcan be as follows:

1 — protection against vertically falling drops of water;
2 — from water drops with a deviation of up to 15 ° from the vertical axis of the device;
3 — from water drops with a deviation of up to 60 ° from the vertical axis of the device (the minimum level that allows the device to be operated in the rain);
4 — from splashes from any direction;
5 — from jets from any direction;
6 — from sea waves or strong water jets;
7 — the p...ossibility of short-term immersion to a depth of 1 m (without the possibility of continuous operation in immersed mode);
8 — the possibility of long-term immersion to a depth of more than 1 m (with the possibility of continuous operation in immersed mode).

Of course, outdoor panels are not designed for immersion under water — the last two options only characterize a high degree of moisture resistance.

In some models, one of the numbers may be replaced by the letter X — for example, IPX7. This does not mean that there is no protection, but that the corresponding parameter was not certified according to the IP standard. At the same time, the degree of non-certified protection can be quite high — for example, the example above corresponds to the possibility of complete immersion under water, which requires a high degree of closeness (minimum dust resistance level 5).

— Plastic. Plastic is characterized by low cost with good performance; besides, it can take on almost any colour. On the other hand, its strength is relatively low: it is enough for most everyday situations, but plastic resists hooliganism and vandalism poorly. Therefore, this material has not received wide popularity in calling panels.

— Metal (anti-vandal). The main advantage of the metal is its high strength, and, accordingly, resistance to damage, which made it possible to call this material "anti-vandal"; in addition, it is resistant to temperature extremes and ultraviolet, and it looks solid. The only drawback of metal in the case of outdoor panels is a higher cost than plastic; however, the difference in price is small and most often completely offset by the advantages of metal cases.

The operating temperature range of the call panel is the air temperature at which the device is guaranteed to remain operational.

If the panel will be used in a residential apartment, house, office or other premises with similar conditions, you can ignore this indicator: all modern models have a temperature range that is more than sufficient for such conditions. But if the device is planned to be installed on the street, it is necessary to make sure that its operating temperatures correspond to climatic features. It is worth noting here that nowadays panels are produced both for very cold weather (-30 °C and below), and for extreme heat(+50 °C and more). A high temperature threshold is also important if the device will be exposed to direct sunlight — under sunlight, the case can heat up to very high temperatures, noticeably higher than that of the surrounding air. And some models combine frost and heat resistance.