Digital video intercom: principles, requirements and future trends

Principle of Digital Video Intercom Technology

The structure of a digital video intercom system generally includes several modules: indoor unit, stair entrance unit, switch, management unit, etc.

When a visitor comes, he dials the designated indoor unit through the elevator entrance machine. The elevator entrance machine digitizes the visitor's audio and video information, encodes and compresses it, and transmits it to the designated indoor unit. The indoor unit receives the audio and video signal transmitted from the network, decompresses and displays it, and after confirming the visitor's identity, presses the unlock button to unlock the door at the elevator entrance. At the same time, VoIP is also implemented between the elevator entrance machine and the indoor unit, and the two terminals can realize two-way voice intercom, providing the owner with further communication and confirmation needs for identifying the identity of the visitor.

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The system provides two-way video and voice transmission between two indoor units or between an indoor unit and a management unit. In terms of function realization, both the entrance unit and the management unit can be attributed to the indoor unit. The indoor unit has the most comprehensive functions, realizing audio and video compression transmission, receiving decompression display and echo cancellation functions, and can also be used as a terminal for realizing various network value-added services.

Traditional building video intercom products are gradually developing in the direction of digitalization, networking and intelligence. In addition to video intercom, remote unlocking, alarm and other functions, video intercom products also realize remote video monitoring, abnormal alarm, access control, three-meter copy, information release, smart home control, Internet access and video on demand and even mobile phone linkage and other value-added services. Most of these products have built-in powerful SoC processors and touch TFT display screens, especially the standard network function, which brings more imagination space to the products. More and more digital media functions such as PVR, DPF digital photo frame, video phone, media player, etc. will be integrated. Digital video intercom quietly plays the role of another center of the digital home.

Digital video intercom product requirements

(1) Security

Video intercom products are security products, and their basic function is still to meet the security needs of families and communities. Therefore, users hope that the video intercom system can provide further security functions while providing video calls and remote unlocking. For example, the activities of the elderly and children at home can be monitored remotely when the owner is away, and the management office or the resident himself can be notified immediately (for example, by text message) when there is a fire alarm, gas leak or a thief enters the resident's home.

(2) Stability

Video intercom products are security systems that need to run 24 hours a day, so users require the products to have excellent stability. Only stability can guarantee safety.

(3) Practicality

Only practical products have strong vitality. The practicality of existing products on the market is not high. Some families may only use the video doorbells they install once every one or two weeks because the functions are too simple and impractical. If residents are allowed to choose whether to buy or not, I believe many consumers will choose "no". In order for video intercom products to be popular among families, practicality is the key. If you can browse your own photo collection, check your frequently used phone numbers, and collect monthly expense information through the video doorbell, the utilization rate and attention of the equipment will be greatly improved. Only by improving the utilization rate of the equipment can the product market truly prosper.

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(4) Standardization and openness

Currently, there is basically no standard for video intercom products. Products from different manufacturers are not compatible with each other, and video intercom subsystems are basically unable to connect with other weak electronic systems. The reason is that there is no standard. Without standards, there is a lack of openness, the system cannot be interconnected, the product warranty and service cannot be guaranteed in the long term, and the industry cannot develop healthily. Therefore, the market is very much looking forward to the emergence of standardized and open products.

The release of the draft of the national standard "Digital Application of Property Management in Buildings and Residential Communities" is a great thing that deserves the encouragement of the industry. It points out the direction for the healthy development of the industry. For example, the draft of the standard points out:

Comprehensive security management integrates the perimeter alarm subsystem, patrol management subsystem, closed-circuit television monitoring subsystem, home security alarm subsystem, vehicle management subsystem, and public broadcasting subsystem in buildings and communities on a unified networked integrated security management platform (SMS). Through the centralized and distributed security and anti-theft alarm monitoring and management centers (including remote alarm monitoring and management centers) in buildings and communities, the monitoring, alarm confirmation, operation control, alarm information recording and query are implemented.

The "Standard" emphasizes that comprehensive security management (including video intercom systems) must integrate various subsystems. Standardization and openness are the key. In the general direction, the IP protocol will be the key standard for integrating various subsystems and the easiest way to achieve integration.

(5) Fashionable

In terms of appearance and application, the existing intercom products on the market are hardly fashionable compared with consumer electronic products such as mobile phones, color TVs, and game consoles. As a consumer electronic product for home use, video intercom products must take the path of fashion, achieve novel and unique appearance, and rich and colorful applications, so that the industry can be healthy and prosperous.

Development Trend of Digital Video Intercom

From the perspective of the demand market, the bus structure technology level products have entered a period of flat demand, but the overall market demand is still continuing to heat up. The demand for building intercom products has always been closely related to the development of the real estate industry. In recent years, more than 90% of new commercial real estate projects in large cities have designed this system. From the development trend, the building intercom system is a must-have system for new residential communities. In addition, some old buildings, unit residences, etc. also need to be renovated and equipped with this system. Most new real estate projects at the first level of county towns have not yet involved this system. It can be seen that there are still many blank spots in the market that need to be developed.

The trend of networking is the development of full-service IP data service network for some products: on the basis of the existing video intercom system, using the existing broadband network data transmission platform or building a separate community Ethernet, using voice and video fully digital transmission as a means, with the goal of realizing information storage, forwarding and sharing, through the visual terminal, assigning a video call number based on the IP address to each user, providing users with network videophone, VOIP, video monitoring, community/building intercom, community public information release, video on demand, visual distance education, IPTV and other personalized multimedia services, and can achieve interconnection with the "3G" network. The trend of intelligence is to integrate a whole set of home intelligent functions in the system (including video intercom, closed-circuit monitoring system, parking lot management system, three-meter copy system, background music system, electronic patrol system, access control card system, property management system, broadband network and access system, etc. In simple terms, the trend of smart home is to use ARM embedded technology to access the Internet and telephone signals, convert them into control signals, and achieve interconnection with the supporting home appliance control system through the internal data bus of the home; wireless communication, power line carrier and other methods.

In terms of market products, the development speed of products with these two different technical routes is very rapid. Smart home products can be regarded as a great integration of the previous smart home exclusive field and the existing video intercom field, and the technology is gradually maturing. This field has both some well-known foreign brands and some well-known domestic brands, which are the new forces in the video intercom industry; the technical bottleneck of IP networking is relatively high. In terms of technical maturity, IP network video intercom products have realized the digital collection, transmission, and compression of audio and video signals, and wiring can also be completed directly with an RJ45 network cable and a power cord.

To sum up, the development of video intercom products will move towards safety, stability, practicality, standards, openness, fashion and so on. Only products that meet the needs can lead the development trend of video intercom products.