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Classified by networking
The type of system determines the method of networking. From the perspective of networking, it mainly includes bus networking, semi-digital networking, pure digital networking using the TCP/IP protocol, and wireless intercom systems that have emerged in the past two years. Zhang Zhanlin, product engineering manager of Fujian Guanlin Electronics Co., Ltd. carried out a one-on-one analysis of it.
Bus networking
Bus networking is the use of fieldbus technology (such as RS-485, CAN bus), this type of products are analog type, which uses bus technology to organize the distributed unit subsystems within the community, unified management, and thus constitute a relatively large Community networking system. According to Guan Yuxi, deputy general manager of the intelligent business division of Nanjing Putianji Building Intelligence Co., Ltd., “The bus network requires the use of a 'hands in hand' bus networking approach. It will divide a district into districts according to the distribution of buildings and divide a community into Multiple small partitions; inter-building units in each partition (usually the intercom system with a network interface) or intercom equipment (codec equipment, etc.) in the unit are connected by “hands-in-hand†bus; You can use traditional twisted-pair cables or connect through optical cables between the zone and the management center.
The benefits of this sub-regional transmission are: First, after the cell is divided into multiple partitions, the failure of each partition will not affect other partitions; Second, the partition can be divided according to the actual situation to facilitate the construction of the project. However, one of the disadvantages of analog signal networking transmission is the problem of signal interference. Especially in the case of long-distance transmission, transmission quality assurance of audio and video and control signals is a difficult problem to solve. According to reports, in order to cope with this situation, more manufacturers or engineering companies have had professional technical support personnel involved in the early stage of project construction, considering how to divide the region, how to design for networking, etc. In order to solve the problem of reliability of long-distance transmission, Some manufacturers have used differential video transmission, optical transmission and other technologies to ensure that networked audio and video have a better effect.
· Pure digital networking
· Pure digital networking means that both internal and external equipment and signal transmission in cell units adopt network digital devices and standard TCP/IP transmission protocols. These products are all-digital, including indoor and outdoor networking equipment in buildings. Similarly, Guan Yuxi of Nanjing Putian emphasized: “These products and networking methods have strong anti-jamming capabilities, networking is also more convenient, and it is easy to expand the system. Through the digital and network transmission technologies, the entire community can be built with video intercom (also With other security and value-added features Ethernet LAN signal transmission, this TCP/IP pure digital intercom system has the advantages of convenient application and flexible networking, but the overall system investment is relatively high.
Semi-digital networking
• Semi-digital networking, where system equipment and networking are between analog and digital, cell networking uses digital and TCP/IP, and intra-cell equipment is analog, and transmission is bus-based. The semi-digital system is a combination of traditional and mature bus technologies and advanced TCP/IP technologies. It can be used for avoiding weaknesses and for avoiding shortcomings. It is suitable for general residential projects with long-distance networking and large communities. It can ensure long-distance transmission problems. Can save costs;
The wireless intercom system has the characteristics of simple debugging and functions because it does not require wiring, and is usually used for single-family and villa-type households that are not networked.
Size
Intercom system can be divided into single-family, unit-type and building-type according to the size. According to Tang Guangyao, the chief engineer of Xiamen Lilin Technology Co., Ltd., "Mainly in China, the main unit types and building types are the main ones. This is mainly due to the emphasis on community networking in community applications and the better united management of unit or building types. Foreign construction is mainly based on single-family villas, which is mainly due to the wide application of the single-family intercom system and the simplest system construction requirements.At present, the two-wire villa intercom system has become the mainstream, ie, the host-to-extension system adopts two-wire connection. When there is a visitor, the guest enters the number of the room door to be called, and the indoor extension sends a ringing tone. (When the night glows, the host's luminous key lights up.) When the owner picks up the machine and talks to the guest, it can be remotely controlled by the unlocking key of the indoor extension. An electronically controlled lock that opens the door, when the guest enters the door, the door closer automatically closes the door."
other
In addition to system size and networking, intercom systems can be divided into several types based on other criteria. There are mainly other classifications as follows.
Functional distinction. Mainly classified as visible/non-visible, He Yunfei, deputy general manager of Shenzhen Three-Dimensional Intelligence Co., Ltd. stated: “In recent years, with the economic development and the vigorous development of the real estate industry, the traditional non-visual gradually withdrew from the market. Currently, the market is mainly based on video intercom.†In addition, the function division can be divided into black and white/color, with access control/without access control, single-function, and multi-function integrated applications such as alarm, information release, and household communication. Type, etc.
Application angle and function division. Zhang Zhanlin, product engineering manager of Guanlin Electronics Co., Ltd. of Fujian Province stated: “From an application perspective, the intercom system can be divided into single-family, villa-type, low-level systems, high-level systems, and large-scale community-based networking systems.
The building intercom system serves as the last barrier to ensure the safety of the residence and is regarded as the “guardian god†of the home life. Before understanding the technical development of the intercom system, the author first discussed with the reader the classification of the intercom system. The access control intercom system is classified from different perspectives and has different characteristics.