Cable products carry important data, images and other information transmission tasks in security systems. Due to the insufficient attention of the user or the engineering firm to the purchase of cable products, problems such as the improper selection of the cable products and the quality problems that affect the entire system engineering are not uncommon, causing certain losses and negative effects.

       As an important connection and transmission medium, wire and cable products are constantly updated and developed in the variety of security products, and their usage is continuously increasing. Since the 1990s, the manufacturing of wire and cable industry in China has developed rapidly. At present, the production scale has ranked second in the world, second only to the United States. According to incomplete statistics, the total output value of China's wire and cable industry reached 160 billion yuan by 2004, and the demand for wire and cable products in the security industry was 2 billion yuan. With the full application of the security system in social life, the wire and cable industry is once again facing enormous development opportunities and broad market prospects.

The development trend of cable in the security industry

First, the wide application of new technology products, product technology has entered a standardized era

       In order to better promote the security industry and ensure the harmonious development of social life and work, security cable products must be developed in a safer and faster direction. China is one of the most important cable product R&D and production bases in the world. Currently, it has fire-retardant and fire-resistant, high-temperature and low-temperature resistant, low-inductance and low-noise, green environmental protection, low-smoke and halogen-free, anti-termite and rodent-proof, water and moisture proof, etc. A series of cable products with unique performance and special structure have already formed certain productivity. With the continuous improvement of social security and system security requirements, through the extensive publicity, promotion and collaboration of governments, industries, and companies, we believe that the above-mentioned high-performance, high-efficiency and safe new technology cable products will surely be similar to the developed countries in the West. That way, it is widely used in security systems.

       Industry standards are the basis for the development of industries and enterprises. Product technical standards are an effective guarantee for product quality. With the development and maturity of China's security industry, the national authorities are pushing for the standardization of the security industry. At present, the development of technical standards for security cable products has been incorporated into the next phase of the work plan. We believe that with the joint efforts of the government, industry, and the company, the production and quality assurance of security cable products will have regulations, laws and regulations, security cable technology and applications will be more reliable. The field of specialization advances rapidly.

Second, industrial concentration continues to increase, and leading companies dominate the mainstream market

       China's security industry has started from scratch and has grown in competition. After decades of development, it has formed a certain scale. With the promotion of global economic integration, there will inevitably be leading companies in the industry with different products, and the degree of industrial concentration will continue to increase. Only industry concentration has emerged in the industry, leading companies emerged and the industry can be established to form a common development philosophy. Only from the perspective of the most basic survival considerations can companies enter the most important areas of scientific management, core technologies, and core products to promote the healthy development of the industry, so as to avoid unfair competition of low quality and low end. The chaotic competition between the large and small, miscellaneous wire and cable manufacturers, the lack of technical strength in the industry, and the size of funds will gradually end for the local interests and vicious competition.

       At present, leading companies in the domestic security industry have begun to show signs, and the domestic security cable market has formed a number of mainstream companies. These enterprises have expanded through continuous product extension and channels, through continuous improvement of enterprise management and team building, whether in the brand The degree of influence or the overall improvement of product quality, service specifications have been increasingly accepted by the industry and users. It is believed that with the continuous improvement of industrial concentration, with the continuous expansion of the production scale of such enterprises, the productivity generated by the scale will be fully reflected in the market, and cost-effective products plus standardized services will occupy the security cable. The vast majority of market share.

Third, users continue to increase the degree of emphasis, "full line of compatibility, full service" ready to appear

       Cable products carry important data, images and other information transmission tasks in security systems. Due to the insufficient attention of the user or the engineering firm to the purchase of cable products, problems such as the improper selection of the cable products and the quality problems that affect the entire system engineering are not uncommon, causing certain losses and negative effects. The profound lessons of the past have led more and more users and engineers to pay close attention to the quality and correct use of cable products, and gradually changed the use of the product. The price of security cable products is dominant. We are delighted to see that through the joint efforts and publicity of the government, industry, engineering companies, and production companies, the phenomenon of the coexistence of high-end equipment and low-quality cables in security engineering systems is becoming less and less, and security cables are used in the system. Its important role is being recognized more and more by everyone.

       Security engineering requires a perfect combination of different functional devices and the reliability of the transmission part of the product is critical to the entire security system. Although the security cable is the main component of the transmission part, the compatibility and consistency of the transmission performance of the cable product between different model specifications and the compatibility, matching, and stability between the cable and the connected related equipment are also frequent. Ignored by industry users. The future security cable manufacturers will not only be limited to the provision of simple products in the current stage, but will also continue to extend the product chain while strengthening the service concept, providing users with a full range of compatible products, and providing the full range of products for the correct and reasonable use. The technical support and service will surely become the market development trend of the security industry.

Fourth, international cooperation and development are not to be

       "To be a global security company and to build an international brand of China's security industry" has become the development goal and corporate mission of outstanding enterprises in the industry. Guided by such beliefs, China's security products have extensively penetrated into many areas of the world's security industry. International cooperation between domestic enterprises and advanced developed countries has been launched in all directions. At present, several of China's most powerful security cable companies are also following the international trend of market development. Several years ago, they have started to fully formulate and launch a global development strategy. They have extensive cooperation and exchanges in technology, capital, and management. The introduction of advanced technology and management concepts of foreign companies has enabled the company's strength to be rapidly upgraded and developed. And actively go abroad to seek international markets, increase product exports, there are a large number of security cable products exported to the rest of the world.

       After more than 20 years of vigorous development, the security industry in China has continuously expanded its scope of application, and its industrial concentration has continued to increase. New technologies and new products have entered the security industry one after another, and the market size of the security industry will grow rapidly. Domestic security cable companies continue to regulate the industry order, the market environment is gradually healthy, while through continuous improvement of their own strength and the continuous extension of products and services, security cable industry as China's security industry is like a spring breeze, it will certainly be booming Let us join hands and work together to deepen the security of this promising industry.

Application of Security Cables in Security Engineering

First, the cable television monitoring system (CCTV system) transmission system

       The CCTV system can image and truly reflect the monitored and controlled objects in real time, enabling all levels of departments and relevant personnel to obtain a large amount of rich information in a timely manner, which greatly improves the management efficiency and the automation level of measurement and control. A set of closed-circuit television monitoring systems with advanced technology, reliable quality, and stable operation has received more and more attention from people, and has become an important basis for measuring whether the management is scaled and modernized. Good video transmission design is a very important part of the CCTV system.

1, coaxial cable

       The main selection of solid-core polyethylene insulated 75Ω RF coaxial cable transmission video signal (the video signal rate is usually 10MHz or less than 10MHz), the main consideration when selecting video signal attenuation and anti-jamming problems. The length of the transmission distance for each specific model wire is related to the front and rear equipment, site conditions and construction quality. According to GB50198-1984 "Civil Closed-circuit Surveillance TV System Engineering Technical Specifications" requirements of the image quality indicators: color television baseband signal frequency point at 5.5MHz when the unevenness shall not be greater than 3dB, or need to add cable equalizer. In other words, the video signal allows up to 3 dB of attenuation during the entire transmission. However, due to the limitations of the inspection conditions in the actual project, most of the acceptances are subjected to subjective assessment according to the image 5-level damage criteria. Therefore, the reference values for the transmission distance of the 75Ω RF coaxial cable commonly used in the monitoring system are as follows:

Under conditions where possible, a signal compensator may be added to the line to extend the transmission distance, but in general the compensator is not used in series (it can enhance the brightness, chroma, and synchronization signals of the video signal, but at the same time the interference signal in the line It will also be amplified, so too many compensators cannot be cascaded in the loop.)

2. 100Ω digital communication cable (twisted pair)

       Due to the coarse coaxial cable, the wiring is not convenient for dense monitoring at multiple points, and there are also defects such as anti-jamming capability in a strong interference environment and difficult adjustment of coaxial amplifiers. Digital communication cable systems can be considered when transmitting over a distance of 1 km. .

In addition to better suppressing common mode interference, a Category 5 cable can simultaneously transmit video, audio, control, and power signals, saving a large number of connection cables. The defect is the use of twisted pair transceivers, which adds on-site equipment and brings with it a series of problems such as installation, lightning protection, and theft prevention. Digital communication cable for CCTV system should pay attention to two parameters: a, because the capacitor has high-passivity, so the capacitance is too large to suppress the low-frequency signal is strong, so the digital communication cable distribution capacitance must be less than 60pF/m; b, double The loop resistance of the strand must be less than 18Ω/100m. These two parameters directly affect the transmission distance and image distortion.

       Therefore, digital communication cables with more than five classes (such as Super Category 5 and Category 6 cables, etc.) must be used in CCTV systems to ensure the system is qualified.

3, optical fiber

       The best choice for long-distance transmission, the signal transmission process from electromagnetic interference. For the built-up living communities and other locations that are not easy to re-trench, the joint transmission of overhead optical fiber and power supply cables is the smallest option and sometimes the only choice. When there are lightning protection requirements, metal-free optical fibers should be used.

       The general backbone network video signal has two kinds of non-compression or compression transmission methods. The biggest advantage of non-compression mode is that the image quality is clear, it can reach the broadcasting level effect, and the transmission has no delay at the same time; the compression mode has a smaller transmission bandwidth, the system is convenient for networking, and the control mode is simple, but the disadvantage is that the signal must be A/D converted first. It can only be uploaded after digital compression and encoding. This series of processes will result in hardware delays. Multiple A/D and D/A conversions will also result in degraded image quality.

For the above transmission methods for selecting different transmission systems, the transmission components and the transmission lines used are quite different. The signal control cable is generally used in an imaging device equipped with an electric pan/tilt head and an electric lens, and a remote control decoder must be installed in the field when it is used. The communication transmission cable between the on-site decoder and the video matrix switching host in the control center generally adopts two-wire twisted shielded wire (RVVSP) or unshielded digital communication cable (UTP). The basic principle of selecting the signal control cable is the distance. Long, the larger the cross-sectional area of the conductor that should be used. For example, the basic communication distance specified by RS-485 communication is 1200 meters, but in actual projects, RVVSP2 x 1.5 shielded wires can be used to extend the communication distance to more than 2 kilometers. When the communication distance is too long, an RS-485 communication repeater is required.

Second, the building intercom cable system

       The connection cables used in building intercom systems currently on the market are mostly signal control lines (such as PVC sheathed cord RVV and shielded electric wire RVVP), coaxial SYV-75 series cables, and the requirements of the system for cables. It is the transmission of voice, data, video and other signals. At the same time, the requirements for cables are also reflected in the quality of voice transmission, the speed of data transmission, the quality and rate of video signal transmission, etc. In building video intercom systems, for connection The quality of the cable is quite high. Cables for transmitting voice signals and alarm signals mainly use 4-core or more PVC sheathed cords (RVV). The SYV-75-5 coaxial cable is used for video transmission. Nowadays, some networks are also used. Twisted-pair transmission includes new techniques for signal transmission, including video, and does not use coaxial lines. If the system is to prevent external interference or not grounded, the cable used in the system must be a shielded cable (RVVP) type shielded cable.

As community intelligence continues to improve, the performance requirements for connecting cables are also increasing. Other cables used include network twisted pair, PVC sheathed line RVV or shielded wire RVVP, video coaxial cable Wait.

The following briefly introduces the video intercom system connection cable.

       The standard of the line-to-line videophone system is that the video, two-way audio and remote unlocking of each indoor unit are connected in parallel with the door machine by bus, but the call lines are connected directly to the door machine. Therefore, there are many cables used in this type of multi-residential video intercom system: video coaxial cable SYV-75-3 or SYV-75-5, microphone/speaker/unlocking line with a 4-core non-shielded PVC RVV or RVVP, power cords generally use 2-core PVC sheathed cords (RVV), and call lines use 2-core shielded wires (RVVP).

       Digital coded push-button video intercom systems are generally used in multi-residential applications in high-rise residential buildings. According to different vendors' equipment systems, the standards for connecting cables are also different, but generally speaking, the basic wiring of the system is: the main lines include video coaxial lines (SYV-75-3, SYV-75-5, etc.), and power lines ( 2-core PVC sheathed cord RVV), audio/data control cable (4-core shielded wire RVVP), household signal wire (6-core shielded wire RVVP), etc.

       Most of the residential buildings where the building's video intercom system is installed have a management center machine, and a community wall machine is installed at the entrance of the community wall to enable residents, management centers and visitors to implement the so-called “three-way call” of technical defense. The wiring of such a networked system adds the interconnection lines between the cell door machine, the cell door machine and the management center machine, generally including the video coaxial line (SYV-75-3, SYV-75-5, SYV-75 -7, etc.) Transmission of video image signals, 4-core shielded wires (RVVP) for transmission of audio and control signals, etc.

       The above mentioned is to select different cables for different wiring according to the transmission of different signals. With the enhancement of cable manufacturers' R&D capabilities, there are also some comprehensive functions available in the market for the use of the access control video intercom system. The cable adopts a specific process structure, so that the cable core assembly includes a coaxial line for transmitting video signals, a signal line for transmitting audio signals, a signal line for transmitting control signals, a power line for transmitting power signals, and the like, so that the primary wiring can be achieved. The required effect can save a large amount of work, but it depends on various