Digital Visual Intercom How to Peg Community Security Engineering

The digital video intercom system based on Ethernet has become a trend of intelligent community development, and the digital intercom system can share the same physical network with the broadband network that has become an integral part of many residential infrastructures. Talk about the integrated wiring cost of the system and the residential broadband network.

This paper takes the digital video intercom system as an example. According to the broadband data actually tested by the system, the digital video intercom is theoretically analyzed for the application of the apartment video intercom system and the villa type video intercom system. The feasibility of the system sharing the physical network with the community broadband.

introduction

The community video intercom system was first introduced from foreign developed countries, but it has achieved rapid development in China. Foreign video intercoms are mainly used in single-family apartments or villas, so the requirements for system networking are generally not high. Domestic video intercom systems are generally used in large communities, many of which are thousands or even tens of thousands of households. However, the video intercom system of the traditional cell is based on a system of analog audio and video signals plus a low rate data communication signal (generally RS485 communication). This kind of traditional system not only has to lay a large number of networked video lines and audio lines and data lines for it, the workload of engineering debugging is large, it is difficult to maintain, and since the analog audio and video system can only transmit one channel of audio and video at the same time, For large cells with large user capacity, the problem of system bus busy is becoming more and more prominent.

Digital video intercom system

With the development of digital multimedia processing technology, the digital processing of audio and video has been widely applied in the fields of 3G networks such as the Internet and mobile phones. The digitally processed audio and video signals not only simplify the physical network transmission, but also allow multiple channels simultaneously. Transmission can completely solve the bus busy problem. It is for this reason that digitizing audio and video signals and digitally upgrading the current traditional analog video intercom system has become a trend in the development of community video intercom systems. The result reflected in the market is that More and more video intercom manufacturers have developed a pure digital video intercom system and gradually applied it to practice.

Ethernet is the most common communication protocol standard technology used in today's local area; since it was successfully developed by Xerox in 1975, it has become the preferred network communication technology in IT industry applications. Therefore, for video intercom The digitization of the system, video intercom manufacturers have almost invariably chose Ethernet technology. Therefore, for the inside of the system terminal, each digital visual intercom factory uses different audio and video processing chip solutions. But from a system perspective, the current domestic digital intercom system is essentially a local area network (LAN).

Digital video intercom system and community broadband

Because the digital video intercom system is essentially a local area network, their physical structure is the same, and the wiring is also in accordance with the requirements of the local area network: the main line uses optical fiber, local (usually inside each apartment, or nearby) There are five types of lines between several villas. If the digital analog intercom system is used in the wired mode of the original analog intercom system, the physical network of the local area network should be separately installed in the cell according to the above requirements. However, in practical applications, we will find such a problem: the digital video intercom system is exactly the same as the physical structure of the broadband system in the community, and with the development of Internet technology, the broadband network has become the basic infrastructure of many communities. Components, such as digital video intercom systems, can use the same physical network as broadband networks, which is clearly a more economical digital solution.

However, there are two prerequisites for sharing the same network with the community broadband. One is whether the telecom operator allows the video intercom system to use its network. The second is how much bandwidth the digital video intercom system occupies, and whether the broadband sharing network will It will affect the simultaneous normal use of users in the cell.

The first problem depends on the telecom operators. At present, China Netcom has proposed the concept of “Broadband One Netcom”, which uses the optical fiber network provided by Netcom to interconnect all the intelligent devices in the residential community to realize the combination of multiple functions. And remote control, so in the community using Netcom's broadband Internet access, Netcom can cooperate with video intercom manufacturers to share its physical network with digital video intercom system. In recent years, China Telecom has also introduced a new Ethernet access technology, EPON (Ethernet Passive Optical Network), which is a typical point-to-multipoint passive optical network technology. Point-of-light network technology has the advantage of saving backbone fiber, saving optical transceivers, and distributing signals from a single fiber to separate users. This advantage greatly simplifies the operation, maintenance and cost of the network system. In addition to meeting the needs of broadband Internet access, EPON can also be used as a bearer for other service networks to reduce costs. Therefore, digital intercom systems can also share their physical networks when telecom companies use EPON technology to access the Internet.

Another problem should be said to depend mainly on the audio and video processing technology used in the digital video intercom system, that is, the bandwidth occupied by the audio and video data after digitization. Because the audio and video data of the video intercom system occupies less bandwidth, it is possible that it does not affect the Internet application of broadband users, and it is possible for the telecom operator to agree to share the physical network with it.

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