Security system refers to the public security system which is composed of security products, related science and technology and management methods for the purpose of maintaining public security. It includes TV monitoring system, intrusion alarm system, access control management system, visitor intercom system, building intercom system and parking lot automatic access management system. < / P > < p > TV monitoring system is the application of TV technology in the field of security protection, which is an advanced and comprehensive system with strong security protection ability. Its main function is to monitor the scene through the camera and its auxiliary equipment, and transmit the monitored images and sounds to the monitoring center. Generally, the TV monitoring system is composed of four parts: camera, transmission distribution, control, image display and recording. When the system works, the optical and acoustic signals of the monitored target are transformed into electrical signals by the camera part, and then sent to the transmission and distribution part. The transmission and distribution part feeds the video signal output by the camera to the central computer room or other monitoring points. Through the control part, the system can remotely control the equipment of the camera and transmission distribution part of the system through the relevant equipment in the central machine room. The image signal transmitted by the system can be switched, recorded, replayed, processed and copied by relevant equipment. < / P > < p > A. camera. Camera is the most basic front-end equipment in the TV monitoring system. Its function is to transform the optical image of the object into electrical signal and provide signal source for the system. According to the type of camera device, the camera can be divided into two categories: electric vacuum camera and solid-state camera. The solid-state camera is a new type of camera device developed in recent years, which has the advantages of long life, light weight, no magnetic interference, good seismic resistance, no residual image and no fear of target burning. With the continuous improvement of its technology and the gradual reduction of its price, it has gradually replaced the electric vacuum camera tube. < / P > < p > B. lens. Camera lens is an indispensable part in TV monitoring system. Its quality directly affects the whole camera index. According to its function and operation method, camera lens can be divided into three categories: fixed focus lens, zoom lens and special lens. < p > < p > C. pan tilt. PTZ is a kind of worktable used to install cameras, which can be divided into manual and electric. The manual pan tilt is fixed on the support by bolts, and the camera direction can be adjusted within a certain range. Generally, it can be adjusted from 150 ° to 300 ° in horizontal direction and ± 45 ° in vertical direction; electric pan tilt can be driven by micro motor to rotate horizontally and vertically, and different products have different rotation angles. < / P > < p > D. In order to make the camera part work normally in various environments, it is necessary to use protective cover to protect it. There are many kinds of protective covers, mainly including indoor, outdoor and special types. The main difference of indoor protective cover lies in its size, shape and surface treatment, which mainly aims at decoration, concealment and dust prevention; while the outdoor type, because it belongs to all-weather application, needs to adapt to different use environment. < / P > < p > ② transmission part. The transmission part is used to complete the data transmission of the whole system, including TV signal and control signal. The TV signal flows from the camera in front of the system to the control center of the TV monitoring system, and the control signal flows from the control center to the camera and other controlled objects. < / P > < p > in the TV monitoring system, the transmission mode is mainly determined by the distance of transmission and the number of cameras. When the transmission distance is short, the video transmission mode is adopted; when the transmission distance is far, the radio frequency cable transmission mode or optical cable transmission mode is adopted. Control part. The control part is the center of TV monitoring system. It includes main controller, sub controller, video matrix switcher, audio matrix switcher, alarm controller and decoder. Among them, the main controller and video matrix switcher are necessary equipment in the system, which are usually integrated into one. The structure diagram is shown in Fig. 10-6. < / P > < p > as shown in Fig. 10-7, it can be seen that the monitoring center of the building is set on the first floor, which is supplied by the monitoring room on the first floor. The camera, monitoring machine and required power supply are installed, and the operation of the monitoring room is set up. < p > < p > syv-75-5, BV-2 × 1.5 and rvvp-2 × 1.0 are used for video cable, BV-2 × 1.5 for power cable and rvvp-2 × 1.0 for camera communication line. The video cable, power line and communication line in the system are laid in a total of 25 pc tubes. < / P > < p > four infrared and microwave dual detection detectors are installed on the second floor of the building and installed on the ceiling; nine infrared and microwave dual detection detectors, three emergency call buttons and an alarm bell are installed on the first floor. < / P > < p > it can be seen from Fig. 10-8 that there is a ceiling pipe near each camera to the security alarm junction box through the weak wire trough; the emergency alarm button, alarm bell and infrared and microwave dual detector are directly led to the junction box. The intrusion alarm system can be divided into several subsystems and extended to hundreds of defense areas. It can be combined with multiple hosts and even different hosts in multiple buildings, which can be deployed and displayed in one place. Some hosts can also be integrated with the access control and monitoring system. The access control module and small matrix system can make the alarm host have the comprehensive performance of alarm, visual, access control and other systems. The intrusion alarm system is mainly composed of front-end detector, alarm host, alarm center and linkage equipment. The front-end detectors mainly include passive infrared detector, microwave detector, glass broken detector and vibration detector. There are also several kinds of technology composite detector, such as infrared + microwave detector, infrared + dynamic monitoring detector and so on. < p > < p > the intrusion alarm system uses infrared, microwave and other detection technologies. In unattended parts, the intrusion signal is transmitted to the alarm host through wireless or wired mode, and the alarm information can be automatically dialled to the alarm center or individual for quick response. < / P > < p > in the anti-theft alarm system, the detector is installed on the scene to detect and forecast various dangerous situations. When there is an intrusion, the alarm signal is sent to the alarm host through the transmission system. The electrical signals sent to the alarm host by the signal transmission system are further processed by the controller to judge whether there is “or” no “dangerous signal. If there is a dangerous situation, the controller will control the alarm device to send out sound and light alarm signals, so as to arouse the vigilance of the personnel on duty. < / P > < p > figure 10-9 shows the intrusion alarm system of a building. In Figure 10-9, the IR / M detector has 20 points in total. Among them, there are 4 entrances and exits on the first floor, one on the left and one on the left and one on the two ends of the corridor on the second to eighth floors, a total of 14. < / P > < p > from this figure, we can also see that the system extender “4208” is a bus system 8-area expander, one for each layer. Among them, “4208” on the first floor is the expander of zone 4, and the “4208” of floor 3-8 is the expander of zone 6. The host 4140xmpt2 of this system is a large multi-functional host. The host has nine basic connection zones, which are bus structure. It is very convenient to expand the defense area. It also has the functions of multiple passwords, setting defense time, automatic dialing and “black box” recording. < / P > < p > access control system is also called access control system. Usually, cards or pre-determined passwords of various levels are made in advance. Magnetic card recognizer or password keyboard is installed at the entrance and exit of relevant gates. Users can only pass and enter with valid cards or input passwords. Access control system is generally linked with anti-theft alarm system, closed-circuit television monitoring system and fire-fighting system, so as to achieve effective security. < p > < p > 1. Card readers can be divided into contact card reader and induction card reader. There are differences between them with or without password keyboard. < / P > < p > the card reader is set at the entrance and exit, through which the parameters of the door access card can be read in, and the parameters read can be judged and analyzed by the controller. Access to open the electric lock, personnel can pass by themselves. If it is forbidden to enter, the electric lock will not act, and can immediately alarm and make corresponding records. < / P > < p > ② electric lock. There are three types of electric locks used in the entrance and exit control system, which can be flexibly selected according to the specific situation of the door. Electric Yin lock and electromagnetic lock are generally used for wooden and iron doors; electric plug locks are mostly used for glass doors. The electric cathode lock is usually powered on to open the door, while the electromagnetic lock and electric plug lock are powered on. < / P > < p > ③ controller. The controller is the core of the access control system. It is composed of a microprocessor and the corresponding peripheral circuits. The controller is the brain of the access control management system. It determines which card is a valid card registered in the system and whether the card meets the limited authorization, thus controlling whether the electric lock is opened. < / P > < p > access control management system is used to control the access to buildings or some special areas. The entrance and exit control system uses a personal identification card to send a personal identification card to each person who has the right to enter. The system judges whether the card holder can enter or leave according to the card number and current time of the card. The entrance and exit control system is installed in the main management area, entrance and exit, elevator hall, main equipment control center machine room, valuables warehouse and other important parts of the building, which can effectively control the flow of personnel, and can timely query the access of staff. At the same time, the system can also be used as attendance statistics. In case of illegal entry, the alarm can also be realized. Huawei has finally made a choice! Xiaomi and ov have also followed up. Have you ever thought about today?