Comparison Dahua DH-VTH1550CHW-2 vs Dahua DH-VTH1660CH

Regular installation method provided in the intercom. This parameter is relevant for models that are not portable (see "Execution"), the options may be as follows.

- Mounted. Installation by hanging on studs, hooks or other similar fasteners. This method is the simplest, besides, if necessary, the intercom can be moved to another place without much difficulty; and there are no obvious shortcomings in the hinged installation. Therefore, this option is used by most stationary (not portable) intercoms.

- Embedded. Mounting, in which the body of the device is hidden in the wall recess, and only the control panel is located outside. The latter is almost flush with the wall surface, due to which the intercom takes up a minimum of space, and also looks stylish and neat. In addition, such a device cannot be thrown to the floor with a careless movement, while mounted models have such a possibility. On the other hand, the installation of built-in intercoms is much more difficult due to the need to prepare a niche, and these advantages are not often key. Because of this, this option is rare, mainly in premium models designed for rich interiors.

The number of alarm inputs provided in the design of the intercom.

Such inputs allow the intercom to receive service signals from other elements of the security system — various sensors (motion, opening, temperature), cameras and video surveillance recorders, etc. This provides additional features for setting up the security system for certain events: for example, you can provide automatic activation of the video intercom camera when an opening sensor on an external wicket or gate is triggered. The specific functionality of alarm inputs for each model should be specified separately; however, anyway, such connectors allow you to increase automation and reduce dependence on the human factor. And the number of such inputs corresponds to the number of control components of the security system, which can be simultaneously connected to the intercom directly, without the use of additional equipment. Most often, it ranges from 3 to 8, and in some models it reaches one and a half dozen.

The number of alarm outputs provided for in the design of the intercom.

Alarm connectors are used to exchange service signals between individual components of the security system, most often to automatically turn on a particular function. The presence of alarm outputs in the intercom allows you to transmit control signals from it to other security devices — locks, spotlights, surveillance cameras, a siren, etc. For example, you can configure the system so that when you press the call button, not only the video intercom camera, but also external surveillance cameras.

The specific functionality of alarm outputs for each model should be specified separately; however, anyway, such connectors allow you to increase automation and reduce dependence on the human factor. And the number of such outputs corresponds to the number of controlled components of the security system, which can be simultaneously connected to the intercom directly, without the use of additional equipment. However, for a number of reasons, this number rarely exceeds 1.

— Android OS. The advantages of the Android OS include flexibility, which allows you to install third-party applications, thereby increasing the functionality of the device. Such applications may include SIP phones, programs that allow video surveillance, and others. But it is worth noting that such devices are not very suitable for the role of using a full-fledged tablet; firstly, most have a stationary location, and secondly, as a rule, the power of intercoms is not so high. Also, various restrictions may be set separately by the manufacturer; this must be clarified separately.

— Wi-Fi module. The Wi-Fi wireless communication module is found only in IP intercoms(see “Device type”). This function allows the device to connect to the network wirelessly - this is much more convenient than pulling cables, and the quality of communication is usually indistinguishable from a wired one. Another option for using Wi-Fi is a direct communication to a smartphone or tablet and using such a gadget as a remote control with an external screen; however, such an opportunity is provided relatively rarely.

- Mobile app. This feature means that the device can be operated 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; ho...wever, 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 a device through a gadget that you can always keep with you is definitely more convenient than going to an intercom or other stationary equipment every time.

— SIP protocol. The intercom's support for the SIP protocol allows the intercom to redirect the signal from the calling panel through the telephone network to a mobile device, a stationary PBX or a computer with the appropriate software. Such a function may be useful, for example, in an office where there are a lot of visitors, and going up to the intercom every time to answer is inconvenient. Additional SIP capabilities in different models may vary significantly; they should be clarified separately.

- DVR support. The ability to operate the intercom in video recording mode from calling panels or from separate surveillance cameras. In most of these models, recording is not carried out constantly, but only when the call button is pressed or another event occurs - for example, a motion detector is triggered (see below). Video is most often saved to a memory card (see “Card Reader” below). In any case, this function allows you to find out who called the intercom at “inopportune hours”; it can also be useful in other situations - even to restore the picture of an emergency that came into view of the cameras.

— Internal communication (Intercom). This function allows you to make calls between intercoms on the same network. Depending on the implementation and settings, there is an addressable intercom, when you enter the number (identifier) of the device on the network to which you want to make a call, as well as options for setting up a general call, when the call goes to all devices on the network. In any case, this function will be useful if there are several intercoms in the network, so you can call, for example, a neighbor.

- Speakerphone. A hands-free function similar to that found in telephones. In this mode, a loud speaker and a sensitive microphone are used for conversation, located in the intercom body and allowing you to communicate comfortably at some distance from the device (up to a meter, or even more). This function is especially important for models with a handset (see “Execution”) - it allows you to talk without holding the handset. But devices without a handset, by definition, operate in a hands-free format.

- A voice message. An analogue of the answering machine function in phones, when the subscriber can leave a message if the owner of the intercom does not respond to the call. The function can be implemented in different ways, but in any case it is similar to the one with the usual expression: “Leave your message after the sound signal...”.

— Picture in picture. The ability to display a second image on the intercom screen, in addition to the main image. In this way, you can, for example, check the situation in the visibility range of a surveillance camera without interrupting communication with the visitor via the main video panel. The additional picture is small in size and is usually displayed in one of the corners of the screen.

- Motion Detector. A function that allows the intercom to detect movement in the visibility range of connected cameras and respond to it. The specific method of such a reaction may be different in different models: turning on recording, sending a notification to a user-specified device, sending a signal to an alarm output, etc.; These details should be clarified separately. In any case, the motion detector reduces the likelihood of missing significant events in the field of view of the cameras.

— Built-in memory. Built-in memory is found in video and IP intercoms (see “Device type”) and is usually intended for storing data from surveillance cameras. However, the volume of such memory is usually small, and it is usually used only for photographs (for example, to capture the faces of visitors); Video recording, if provided, is carried out on a memory card (see below). In any case, it would not hurt to clarify the operating features of the built-in memory separately.

- Frame. The ability to operate the intercom in digital photo frame mode - when photographs stored in the device’s memory (or stored on a memory card) are displayed on the screen (usually in slideshow mode). A mandatory feature of models with this function is a fairly large color screen - only on it photos will be normally visible; The intercoms themselves are usually video or IP models. The main purpose of the photo frame mode is aesthetic: showing beautiful pictures, the intercom plays the role of additional decor for the number.

Diagonal size of the intercom's own display.

In modern intercoms, there are displays ranging in size from 2 "to 10" — smaller screens are non-functional, larger ones are unreasonably bulky and expensive. At the same time, you can normally view the image on almost any display from this range — if you lean close enough to it.

With all this in mind, it makes sense to specifically look for a large screen (10 ") if you need to see it normally from a long distance (a metre or more), or if you do not want to strain your eyes once again, peering into a small image. Golden the middle is the 7" display.

The presence of touch buttons in the design of the intercom.

Unlike mechanical ones, such buttons do not need to be pressed in — they do not work by pressing, but by touch, which is somewhat more convenient. However, the main advantage of touch panels is still in a neat appearance and resistance to dirt. Such panels look modern and technologically advanced, they do not have protruding buttons that make it difficult to clean, and there are no gaps between the buttons and the panel itself, where dirt can accumulate. However they are somewhat more expensive and more difficult to manufacture than push-buttons; this is imperceptible to the average user, but is a disadvantage for manufacturers. That is why sensors, for all their advantages, have not supplanted traditional buttons.

A device for working with removable memory cards. Like built-in memory (see above), such media are used to record data from video panels and cameras; At the same time, for intercoms with card readers, the presence of a DVR is almost mandatory (see above), and it is the video that is saved to the memory card. This is more justified than using built-in memory for this purpose: removable media is cheaper per megabyte of volume and is better suited for large files, such as video recordings. In addition, we note that the card can be removed and installed in another device - for example, to copy footage to a computer or view it on a smartphone. The card may come included, but more often it must be purchased separately. It is worth considering the type and format of media supported by the card reader, as well as the maximum amount of memory with which it is compatible.