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A basic knowledge of the basic wiring system of the computer room
The so-called integrated wiring system refers to the preparation and arrangement of communication lines of various systems in various buildings (or buildings) in a standard, unified and simple structured manner, including network systems, monitoring systems, power systems and lighting systems. Wait. Therefore, the integrated wiring system is a standard and general information transmission system.
First, the development process of integrated wiring
Looking back at history, the development of integrated wiring is closely related to building automation systems. Traditional wiring such as computer LANs are independent. Each system is designed and installed by different manufacturers. The traditional wiring uses different cables and different terminal sockets. Moreover, plugs, sockets, and patch panels that connect these different wirings are not compatible with each other. Office layout and environmental changes are common. If you need to adjust office equipment or need to replace equipment as new technologies develop, you must replace the wiring. In this way, the old cables that were left unused due to the addition of new cables have been used for a long time, resulting in a pile of messy cables in the building, causing great hidden dangers. Inconvenient maintenance and transformation are also very difficult.
With the deep development of global social informatization and economic internationalization, people's demand for information sharing is becoming more and more urgent, and a wiring scheme suitable for the information age is needed.
AT&T's Bell Labs experts have been the first to introduce SYSTIMATMPDS (Building and Building Complex Cabling System) in the late 1980s, based on years of research and success in office buildings and factories. ), the structured cabling system SCS has been introduced. Named as the integrated wiring GCS (Genericcablingsystem) by the national standard GB/T50311-2000 of the People's Republic of China. Integrated wiring is a type of pre-wiring that can accommodate longer periods of time.
Second, the characteristics of integrated wiring
Compared with traditional wiring, integrated wiring has many advantages, which cannot be compared with traditional wiring. Its characteristics are mainly reflected in its compatibility, openness, flexibility, reliability, advancement and economy. And it also brings a lot of convenience to people in design, construction and maintenance.
(1) Compatibility: The primary feature of integrated wiring is its compatibility. The so-called compatibility means that it is completely independent and has nothing to do with the application system, and can be applied to a variety of application systems.
In the past, when wiring a voice or data line in a building or a building group, cables, wiring sockets, and connectors produced by different manufacturers were often used. For example, user switches usually use twisted pairs, and computer systems usually use thick coaxial cables or thin coaxial cables. These different devices use different wiring materials, and the plugs, sockets, and terminal strips that connect these different wires are also different and incompatible with each other. Once you need to change the location of your terminal, you must lay new cables and install new ones and connectors.
The integrated wiring integrates the signal lines of voice, data and monitoring equipment into a unified layout and design, and uses the same transmission media, information sockets, cross-connect equipment, adapters, etc. to integrate these different signals into a standard set of wiring. It can be seen that this kind of wiring is much more simplified than the traditional wiring, which can save a lot of materials, time and space.
When in use, the user does not need to define the specific application of the information socket of a certain work area, only a certain terminal device (such as a personal computer, a video device, etc.) is inserted into the information outlet, and then the handover device between the management room and the device. The corresponding wiring operation is performed, and the terminal device is connected to the respective system.
(2) Openness: For the traditional wiring method, as long as the user selects a certain device, the wiring mode and transmission medium suitable for it are selected. If you replace another device, the original wiring will be replaced. For a building that has already been completed, this change is very difficult and requires a lot of investment.
Due to its open architecture and compliance with many international standards, integrated cabling is open to almost all well-known manufacturers, such as computer equipment and switch equipment. It also supports all communication protocols, such as ISO/IEC8802-3, ISO/IEC8802-5, etc.
(3) Flexibility: The traditional wiring method is closed, and its architecture is fixed. It is quite difficult, even impossible, to migrate equipment or add equipment.
The integrated wiring adopts standard transmission cables and related connection hardware, and is modular in design. Therefore all channels are universal. Each channel supports terminals, Ethernet workstations, and Token Ring workstations. All equipment is turned on and changed without changing the wiring. Simply add or remove the corresponding application equipment and perform the necessary jumper management on the distribution frame. In addition, the networking can also be flexible and diverse, even in the same room can have multiple user terminals, Ethernet workstations, Token Ring network workstations coexist, providing the necessary conditions for users to organize information flow.
(4) Reliability: The traditional wiring method is often incompatible with each other, so there are often multiple wiring schemes in a building. Therefore, the reliability of the building system is guaranteed by the reliability of the wiring used. When the application systems are not properly wired, cross interference will also occur.
The integrated wiring uses a high-quality material and a combination of crimping to form a high-standard information transmission channel. All trunking and related connectors are ISO certified, and each channel uses a dedicated instrument to test the link impedance and attenuation rate to ensure electrical performance. The application system wiring adopts point-to-point termination. Any link failure does not affect the operation of other links. This provides convenience for the operation and maintenance of the link and troubleshooting, thus ensuring reliable operation of the application system. Each application system often uses the same transmission medium, so it can be used alternately, which improves standby redundancy.
(5) Advanced: Integrated wiring, using fiber-optic and twisted-pair hybrid wiring, which constitutes a complete set of wiring.
All cabling uses the world's new communication standards, and the links are all configured with eight-core twisted pair. Category 5 twisted pair bandwidths up to 100MHz, Category 6 twisted pair bandwidths up to 200MHz. For the needs of special users, the fiber can be brought to the desktop (FiberToTheDesk). The voice trunk part is made of steel cable, and the data part is made of fiber optic cable, which provides sufficient bandwidth capacity for transmitting multiple real-time multimedia information at the same time.
(6) Economical: Integrated wiring has economic advantages over traditional wiring. The main integrated wiring can adapt to a long time requirement. The traditional wiring modification is time consuming, and the loss caused by delaying work cannot be calculated by money.
According to the above discussion, the integrated wiring solves many problems in the traditional wiring method. With the rapid development of science and technology, people are increasingly demanding the sharing of information resources, and the communication network is gradually moving to the integrated service digital network ( ISDN) transitions more and more attention to integrated communication networks that provide simultaneous voice, data and video transmission. Therefore, the replacement of single, expensive and complicated traditional wiring by integrated wiring is a requirement of the "information era" and an inevitable trend of historical development.
Third, the integrated wiring system
The integrated wiring system should be an open structure, should be able to support a variety of computer data systems, and should also support the needs of systems such as conference television and surveillance television.
The integrated wiring system can be divided into six subsystems: work area subsystem, wiring (horizontal) subsystem, trunk (vertical) subsystem, equipment room subsystem, management subsystem, building group subsystem.
The engineering design of intelligent buildings and intelligent building parks should be based on actual needs, and the following three types of integrated wiring systems can be selected:
(1) Basic type: It is suitable for the occasion where the configuration standard is low in the integrated wiring system, and the copper core twisted pair cable is used for networking. The basic cabling system configuration is as follows:
â— There is an information outlet in each work area;
â— The distribution cable for each work area is a 4-pair twisted pair cable;
â—Using clip-on handover hardware;
â— There is at least one pair of twisted pair cables for each work area.
(2) Enhanced type: It is suitable for the occasion of the medium configuration standard in the integrated wiring system, and the copper core twisted pair cable is used for networking. The enhanced cabling system configuration is as follows:
â— There are 2 or more information outlets in each work area;
â—The distribution cable for each work area is two 4-pair twisted pair cables;
â— use clip-on or plug-in handover hardware;
â— There are at least 2 pairs of mains cables in each work area.
(3) Comprehensive type, suitable for occasions where the configuration standard is high in the integrated wiring system, and the hybrid network is constructed by optical cable and copper core twisted pair cable. The integrated cabling system configuration should be based on a basic and enhanced cabling system with additional fiber optic cable systems.
The integrated wiring system should meet the transmission rate requirements of the supported data systems, and the appropriate level of cable and transmission equipment should be selected. The integrated wiring system should meet the transmission standard requirements of the supported data and television systems.
All cabling system engineering design, selected cables, optical cables, various connecting cables, jumpers, and wiring equipment, etc., should comply with the requirements of ISO/IEC11801:1995(E) international standards to ensure system indicators. Implemented.
The integrated wiring system should be equipped with Hanxian computer information management system. Manually log in to the working status information of the hardware facilities related to the cabling system. These status information includes: the purpose and usage department of the device and cable, the topology of the LAN, the transmission information rate, the terminal device configuration status, the occupied hardware number and color. The function of the target, the link, the main characteristic parameters, the integrity of the link, and the fault record. You should also log in to the device location and cable to the content as well as the building name, location, area code, floor number, and room number.
When designing the system, the cables, connection hardware, jumpers, connecting lines, etc. selected by the whole system must be consistent with the selected category. If shielding is used, the entire system must be designed as a shield.
Fourth, the standard of integrated wiring
1. Standards Committee
The role of the International Organization for Standardization (ISO) is to ensure that all universal standards are unanimously endorsed by all Member States. ISO is responsible for standards ranging from manufacturing and quality control procedures to electrical and telecommunications distribution cabling systems. In North America, there are four standardization organizations that develop or implement city line standards for the North American market.
The American National Standards Institute (ANSI) was established in the United States in 1918. The organization's main task is the coordination, formalization and adoption of national standards within the United States. ANSI also represents the United States at the ISO Technical Conference.
The Telecommunications Industry Association (TIA) is a separate organization authorized by ANSI. It is also affiliated with the Electronic Industries Association (EIA). TIA's best-known activity is to develop cabling standards for the design and installation of today's structured cabling systems, and to support a wide range of applications in the future and to meet high-speed requirements.
In Canada, all domestic electrical and electronic goods must be approved by the CSA. The product is approved for compliance with all requirements of the Canadian Electrical Code (CEC). CEC refers to CSA related standards. In the process of developing the Putrajaya standard within the TIA/EIA, it was decided that the CSA should participate in further co-development of the structured cabling standard to ensure that Canada's unique requirements are included in the standard.
2. History of integrated wiring standards
The wiring system before 1985 was not standardized. There are several reasons for this. First, local telephone companies are always concerned about their basic wiring requirements. Second, companies using host systems rely on their suppliers to install cabling systems that meet system requirements. As computer technology matures, more and more organizations have installed computer systems, each of which requires its own unique wiring and connectors. Customers began to complain loudly every time they changed the computer platform and had to change the way they routed. To win and maintain market trust, the Computer Communications Industry Association (CCIA) and EIA jointly developed building wiring standards.
Discussions began in 1985 and agreed that both commercial and residential voice and data communications should have corresponding standards. EIA handed over the task of developing cabling standards to the TR-41 committee.
Recognizing the arduous nature of the task, the TR-41 committee established subordinate committees and several working groups to work on a wide range of aspects of developer and residential building wiring standards. The focus of these committees when developing these standards is to ensure that the standards for development are independent of the technology and the manufacturer.
Fifth, the wiring system must use the star topology method
Some fixtures, such as walkie-talkies, security system keyboards, probes and smoke detectors, can be mounted directly using the base wiring. Even though the standard recommends using the star topology method, the fixed device can be connected using a loop or daisy chain.
A sufficient number of communication outlets is required, mainly to prepare for the addition of points in the future. The socket must be installed in all rooms, and the socket is located at some fixed wall.
All new building cables from the socket to the distribution frame must be buried in the pipeline and the cable should not be exposed. For piping or hose design and standards, please refer to ANSI/TIA/EIA-569-A.
The socket must be installed in a fixed position. If an unshielded twisted pair cable is used, the 8-core T568A wiring method must be used. For example, some networks and services need to be connected to special electronic components, such as crossovers, amplifiers, matchers, etc. All electronic components must be installed outside the socket.
Patch panels can be patched, device lines and crossover jumpers to provide an interconnection method or crossover jumper. The channel is standard. Jumpers, equipment lines and crossover jumpers must not exceed 10 meters (33 feet).
Six basic problems of integrated wiring system
1, bandwidth and transmission rate
When it comes to choosing a cabling system, there are two concepts to distinguish between bandwidth (measured in MHZ) and data transmission rate (measured in Mbit/s). It is difficult to make the right choice without distinguishing between these two concepts. For the definition and specific meaning of the two, refer to the relevant technical articles. What is to be pointed out here is the relationship between the two, which is related to techniques such as coding, but not necessarily one-to-one. For example, ATM155, where 155 refers to the rate of data transmission, that is, 155 Mbit/s, and the actual bandwidth is only 80 MHz; as well as 1000 Mbit/S Gigabit Ethernet, it is transmitted due to the 4-pair full-duplex operation. The bandwidth requirement is only 100 MHz. In computer network operations, data transmission rates are widely used, while bandwidth is used in the cable industry, so don't confuse the two.
2, the new cable system
1 Category 5 cable system (Enhanced Cat 5): It is a new cable system that is improved after the performance of some existing 5 types of UPT twisted pair is improved. There are many performance parameters such as near-end crosstalk (NEXT) and attenuation. The crosstalk ratio (ACR) and the like are improved, but the transmission bandwidth is still 100 MHz.
2 Category 6 cable system (Cat 6): A new level of cable system, in addition to a large increase in performance parameters, its bandwidth will be extended to 200MHZ or higher.
Category 37 cable system: The Category 7 cable system is a cable standard proposed by Europe. The planned bandwidth is 600 MHz, but the structure of the connection module is completely incompatible with the current RJ-45. It is a shielding system.
3, quality assurance
When it comes to the quality assurance of cabling systems, each vendor has its own unique performance, some provide several years of product warranty, some provide several years of system warranty, and some provide lifetime warranty. Manufacturers have different interpretations of the content and methods of warranty. The manufacturer's commitment to quality assurance is a good thing for domestic users, and it means that the manufacturer is responsible for the user. But the user must first figure out what the "warranty" guarantees?
First of all, don't take the product or system warranty provided by the manufacturer as a guarantee that the product will not fall behind for many years. With the rapid changes in human science and technology and the rapid development of communication technology, no one can foresee what will happen in a few years, ten years or even decades. That is to say, the manufacturer’s warranty for several years does not guarantee that the system will not Outdated for a period of time. But users can rest assured that a major feature of the cabling system itself is the ease of expansion and upgrade.
The wiring system itself is a passive physical connection system. Once the installation is completed and passed the test, it usually does not need maintenance. It only needs to be properly managed. Therefore, the so-called several-year warranty of the manufacturer is mainly for In terms of the quality of the full range of line products offered in the project. The manufacturer is completely responsible for the quality of the product caused by non-human factors; and the true after-sales service should be completed by the system integrator responsible for implementing the project. Therefore, users should choose products of good quality, get the goods through the formal channels provided by the manufacturers, and select system integrators with good reputation and high technical level to construct them, so that they can get these integrators after getting reasonable profits. Value-added services provided and long-term service and warranty after sale.
4, integrated wiring is not a panacea
When the wiring system first entered China, it gave the Chinese people a mysterious feeling. It seems that once there is a wiring system in the building, it immediately becomes an intelligent building, and each weak current system can use this wiring system. In fact, in theory, the integrated wiring system unifies the transmission medium of each weak current system in the building into a high-performance transmission medium, which makes it easy to manage, maintain and expand. But in fact, at present, we cannot and do not need to do so at home.
1 For example, the security monitoring system, the currently used 75fi coaxial cable is cheap, the transmission distance is far (more than 100m), and its bandwidth is also high; and the 8-core twisted pair cable used in the integrated wiring has no advantage in this respect. In addition, the weak current system such as building automation has its own wiring system. Generally, the topology of the wiring is bus type, that is, many control units can be connected in series on the 2-core line, and the integrated wiring system adopts a star topology, requiring each The root 8-core cable can only be connected to one device. It can be seen that if the weak current system such as building self-control also adopts a star topology, it will require a large number of cables, which will greatly increase the cost of the entire system.
2 Some systems designed separately, separately, and separately managed, such as fire safety systems, are not suitable for integrated wiring.
3 The integrated wiring system provides great flexibility for users who frequently change the type and location of terminal equipment; while weak terminal equipment such as building automation and security monitoring is fixed in a certain position in a room or corridor for a long time, and does not need to be changed frequently. .
It can be seen that the integrated wiring system is not a panacea, it mainly provides the basis for high-performance communication automation systems in intelligent buildings.
5, reasonable choice of integrated wiring system
With the introduction of the Gigabit Ethernet standard, the cabling vendors have also introduced "super 5", "6" or even "7" cabling systems that support Gigabit Ethernet. It is a good thing to introduce advanced products, but users should not be overwhelmed by the hype of the manufacturers. When choosing a wiring product, you should calmly consider whether you need such a high-end system.
Class 1 and Category 5 systems can already meet the transmission requirements of Gigabit Ethernet, and whether it is 155Mbit/S or 622Mbit/S ATM or dry megabit Ethernet, it can only be used as a network backbone at present; Really to the terminal level system, I am afraid that few people in China can use the truly exclusive 10Mbit/S rate. Most LANs still use the 10Mbit/S rate sharing mode. So when the user really wants to transfer data at a rate of 1000 Mbit/s in a horizontal-to-terminal system, I am afraid that the Category 6 system is outdated. Even if some users need 1000Mbit/S transfer rate right away, it is just used to transmit some multimedia information (ie voice, data and images), which is really "overkill". At present, multimedia information transmission applications (such as VOD, video conferencing, etc.) can be realized on ATMs of 25 Mbit/s and 10 Mbit/s on a large network. It is difficult to imagine that users will still use 1000 Mbit/s. What is the rate of the pass.
The standards of Category 6 and Class 7 have not yet been officially introduced. The installation specifications and methods of Category 6 systems have not yet been formed. More importantly, the test specifications and methods for Category 6 or Category 7 systems are not yet available. The commonly used test equipment is still based on the 100MHZ Category 5 system standard, so even if the user uses 6 types of products in the project, it is impossible to know whether the wiring system used meets the requirements of the Category 6 system. What kind of products are considered to be Category 6 products, I am afraid that no one can say clearly.
3 With the rapid development of communication technology, steel cables will eventually be eliminated. The main reasons for elimination are bandwidth, transmission distance, and electromagnetic wave diffusion and interference problems. Instead, it will be a transmission medium for optical fiber or even future. There is information that the all-fiber network has emerged in the United States, and 10Gbit/S Ethernet has also been born in the laboratory. All-fiber LANs will be more attractive to both vendors and users.
6. Finally, how to ensure the quality of the installation.
In addition to the quality of the cabling system itself (usually guaranteed by the manufacturer and usually not the main cause of the problem), whether it is a Category 3, Category 5, Category 5 or Category 6 cable system, it must be completed by construction and installation. The construction process has a great impact on the performance of the cable system. Even if a high-performance cable system is selected, such as Category 5 or Category 6, if the construction quality is rough, its performance may not reach the 5 categories. Therefore, no matter what level of cable system is selected, the final result must meet the corresponding performance, which means that the installed cable system needs to be certified to the relevant standards to ensure. The current situation is that the Category 5 twisted pair system has been certified, and the Category 5 system has been introduced at the end of 1998. As for the Category 6 system, the standard still needs to wait.