With the increasing number of modern residential quarters, building intercom systems are gradually approaching the lives of ordinary people, and building visual intercoms have become an indispensable category of modern building intercom systems.
1. Host
A strobe and intercom control device installed at the entrance of a building security door. The mainframe is usually installed on the security door at the entrance of each unit or on the wall near the security door.
1) The composition of the host: the door host includes a panel, a bottom box, an operation section, an audio section, a video section, and a control section
A. Panel: The operating surface of the host is exposed on the mounting surface and provides the user with the operation. The panel of the building intercom system host is generally required to have a metal texture, and it is mainly required to achieve a certain degree of protection to ensure that the host is robust and durable. There are also panels of plastic texture, which are generally used for early products and single-use machines;
B. Bottom box: The installation of the host computer is a buried burial (surface mounted) box, which is mainly fixed by a bottom box (usually with a buried wall installation, a door installation, etc.), and the panel of the host is then fixed on the bottom box. The materials used for the bottom box of the host machine are based on different manufacturers' metal bottom boxes and plastic bottom boxes, but the main principle is solid, avoiding the extrusion deformation caused by concealed installation.
C. Operation part: Operation is the most basic requirement of the host computer. The operation part is all on the panel of the host computer. Usually it consists of the operation key part and the operation display part. The operation keys (direct press type keys and digital numeric keypad) generally have two kinds of metal keys and plastic keys according to the texture, and the metal keys are sturdy and durable (the host key is the most frequently used part, and the sturdiness and durability should be the first consideration. The use of the bank teller machine button on the market today is a case where the life of a single button is more than a million times. However, the disadvantage of the metal button is mainly night display (some manufacturers' products have basically solved the problem of displaying metal buttons at night). The transmissive ability of the plastic buttons is relatively strong, but the disadvantage is that the durability is not strong, and the keys are prone to aging and damage.
D. Audio Part: The audio part of the host is composed of a speaker and a microphone head, and it mainly performs audio playback and audio reception. The audio part is inside the host.
E. Video part: The video part of the host consists of a camera. It completes the host's image acquisition and sends it to the extension's display through the video channel. At present, the video part of the building's video intercom system host is limited by the space. The camera basically uses a single-board machine, and there is a big difference in the performance of the camera with the professional surveillance system: the pixel is low (the building visual intercom system extension The display screen can only reach 380 lines, the host's camera is usually used in products below 480 lines, and the backlight performance is poor. (Because the volume of the single-board machine is limited, the camera used in the building intercom system generally does not have the function of backlight compensation. It is only simple. The electronic shutter) and illumination limit (the black and white camera illumination in the building intercom system is all around 0.1 LUX, and all use the infrared light compensation function, but the distance is limited). Due to the above reasons, the optimal monitoring range of the host video part of the building intercom system is generally within 0.5 meters from the host (further distances can be seen but the resolution will be reduced).
F. Control section: The control section of the building's visual intercom system is located inside the mainframe and consists of one or more circuit boards, depending on the function.
2. The classification of the host
A, according to the host's operating mode is different: the host (according to different manufacturers, there are door machine, front door and other different titles) is divided into direct-type host, digital host;
a. Direct-press type host: The panel of the host has many buttons corresponding to the resident. Each button corresponds to a resident. Press the button to call the designated resident. The biggest advantage of the direct press type host is that it is easy to operate. Each button represents a resident, and the button has the room number of the resident. The operation is simple. The biggest drawback is the lack of functionality;
b. Digital host: There is a numeric keypad on the panel of the host. According to the number of the room of the resident, different numbers of key combinations can be used to call the resident. This type of host is basically applied to the digital building intercom system. The biggest advantage of the digital host is its strong functionality. Customers can perform functions such as password unlocking on the host. The biggest drawback is that the operation is relatively complicated, visitors must clearly understand the room number of the resident and can accurately operate on the host computer. In actual use, there will be problems in the contact person who do not know how to use, so the general digital host There are basic operating instructions on the panel to improve the operability of the digital host. Digital hosts have a display to remind users of what they press. The general digital host uses four LED digital tubes to display the room number. The updated system uses the LCD display to display the Chinese characters (and can be programmed with Chinese menus). All the instructions are in Chinese during the operation. Easy to use.
B. Make the number of users different according to the actual situation: the host is divided into single-family host, multi-family host, building host;
a.Single-family host computer: The host computer is used in a system with only one occupant. Generally, it is mostly a villa, warehouse, factory building, etc. The user corresponding to this host computer is the only one. Most of the single-host computers are direct-press host computers. ;
b. Multi-family host: In a system in which the host uses 30 households or less, in a multi-story (10-storey or lower) home, the number of users corresponding to this host is 2 to 30, in different manufacturers. Among them, the direct press type and digital type host can all be used as a multi-family host;
c. Building-type host: The host computer is used in the system of households with more than 30 households. Generally, it is a high-rise (10 floors or more) residential building. The maximum capacity of this host is generally more than 100 (based on the manufacturer and internal storage capacity Most of the machines can be equipped with 9999 units. The building host is basically a digital host.
C, machine function is different: The host is divided into the intercom host (according to different manufacturers have the title of non-visual host), visual host.
a. Intercom host: The main function of the host is to call the occupants, talk to the occupants, and unlock the occupants remotely. The main channel of this type of host is the control channel (call home function and unlock function) and audio channel (the following will explain specifically);
b. Visual host: The main function of the host consists of calling the occupants, talking to the occupants, unlocking the occupants by remote control, and the host can see the video signal of the host. The channels of this type of host are mainly control channels (calling residential functions and unlocking), audio channels, and video channels (which will be specifically explained below).
3. Network access control system
With the wide application of building video intercom system in various residential areas, many manufacturers integrate the access control system into the door console in the building video intercom system. The following briefly explains the function and application of the access control system: The access control system has There are two major categories of non-networking and networking systems. Due to its use in building video intercom systems, we mainly introduce networked access control systems.
Networked access control systems generally consist of two major components: control equipment (including control software, network controllers, and access controllers) and front-end equipment (including card readers, electronically controlled locks, door magnets and exit buttons). In the building video intercom system, the network controller, access controller, and card reader are integrated in the doorway host, and the networked lines of the building video intercom system and the computers in the management center form a network. The transmission of signals uses buildings. Visual intercom system signal channel (using RS485 communication protocol). Access control systems used in building video intercom systems generally use inductive ID cards and inductive IC cards. Community cards generally use inductive IC cards to complete (because IC cards have more powerful storage functions, many information can be stored in the card). IC cards currently use LEGIC technology and MIFARE technology. Since the LEGIC technology card is used in the military industry in the initial stage of development, compared to the MIFARE technology card, the sensing distance, reliability, data computing capability, and anti-jamming capability are all stronger than those of the MIFARE technology card. However, due to the price, the MIFARE technology is stuck. There are a lot of applications in practice.
In the integrated door-to-door system of the building intercom system, since the card reading part must be on the door opening host, the door opening host must have a part dedicated to reading the card. Inductive cards generally use radio frequency technology. Metal objects shield the proximity card and affect the card's sensing. The induction card part of the entrance host must use non-metallic texture to reduce the shielding of the access control card.
