- To confirm the tension of the cable. When the cable has excess at the two ends, it should be cut to the required length, not rolled and bundled. The distance between the unwound segments at the joint of the cable should not exceed 2 cm. Too long will cause greater near-end crosstalk. During the certification test, NEXT NEXT will fail. At the splice, the outer protective layer of the cable needs to be pressed into the splice and not outside the splice. Because when the cable is pulled by the outside world, the entire cable is stressed, otherwise the metal part of the cable and the connector is stressed, which will make the connection between the connector and the module unstable. In the construction of cable wiring, the pulling force of the cable is limited, generally about 9 kg. Please confirm the tension with the cable supplier. Excessive tension will destroy the symmetry of the cable twist.
- The wiring skills should be standardized. When some construction workers are making lines, they do not follow the 568A or 568B wiring skills, but use the 1 and 2 lines to play white and orange, and the 3 and 4 lines to match. White and green, 5 and 6 lines against white and blue, 7 and 8 lines against white and brown, such lines can ensure smooth lines during the construction process, but their line indicators are very Poor, especially the near-end crosstalk index is particularly poor, will lead to serious signal leakage, resulting in difficulty in Internet access and indirect interruption. Therefore, the project manager must remind the production workers not to make such mistakes.
- There is a plan for anti-interference. In the integrated wiring system, the pipeline of the horizontal cable should be made of steel pipes as much as possible, and the main cables should be laid with bridges as much as possible. The grounding spanning work between the space, the bridge and the bridge. In such a pipeline, we lay unshielded cables and large logarithmic cables in it, which can play an effective shielding role, reduce the impact of external interference on the signal transmission of the integrated wiring system, and make up for the deficiencies of the unshielded wiring system.
- It is better to install the trunking in the ceiling . When installing the trunking, you should consider many aspects. Try to install the trunking in the ceiling of the corridor, and the branch pipes to each room should be properly concentrated near the inspection hole for easy maintenance. The centralized wiring construction should be done before the corridor ceiling, which not only reduces the wiring man-hours, but also facilitates the protection of the already worn cables without affecting the interior decoration. Generally, the corridor is in the middle position, the average distance of wiring is the shortest, which saves cable costs and improves the performance of integrated wiring (the shorter the line, the higher the quality of transmission), try to avoid the wire slots entering the room, otherwise, not only the wire is wasted, but also the room decoration is affected , not conducive to future maintenance
- Distinguish the line sequence of large logarithmic cables In actual construction, there are often problems with the connection of 25 pairs or 100 pairs of large logarithmic cables, and it is not easy to distinguish them. Here, we will provide simple parameters for everyone. Take 25 pairs of cables as an example. The cable has five basic colors, the order is white, red, black, yellow, and purple, and each basic color includes five color sequences, namely blue, orange, green, brown, and gray. That is, the order of all line pairs 1 to 25 is white-blue, white-orange, white-green, white-brown, white-gray…purple-blue, purple-orange, purple-green, purple-brown, purple-gray. For 100 pairs of cables, use 25 pairs of cables as an example. The 100-pair cable is divided into four 25-pair groups with blue, orange, green, and brown ribbons, and each group is wound with each other in the above manner, and we can distinguish 100 wire pairs. In this way, we can hit the terminals of the 110 patch panel one by one. As long as the same general wiring sequence is used in the management room and the equipment room, and then the cable identification work is done, it can be easily used for transmission. phone.
- System structure design The general building wiring system adopts the optical fiber-UTP copper cable hybrid scheme. Considering the structure of the building group and the farthest distance supported by multi-mode optical cables and twisted pairs, a computer center room is set up, and a building wiring room is set up in each of the other buildings. The data backbone system between the building group wiring room and the building wiring room is connected by a six-core outdoor multi-mode optical cable, which can support traditional Ethernet, Token Ring, 100Mb/s Fast Ethernet, FDDI, 622Mb/s ATM, thousands of For various applications such as megabit high-speed Ethernet, the horizontal subsystem wiring adopts Category 5 unshielded twisted pair cables, which can support up to 622Mbps ATM and 550MHz bandwidth image applications, which can more effectively reduce crosstalk interference and enable voice, data and image. The transmission is clearer and more efficient.
- Work area subsystem The work area subsystem provides users with a standard information outlet that meets high-speed data transmission, and realizes the matching and connection between the information port and the equipment terminal. This part mainly includes non-active devices such as jumper wires and soft wires. The data part adopts (RJ45-RJ45) super five crimping jumper wires. Each information socket should support the following terminal equipment: data communication, voice communication, image transfer, etc.
- Horizontal (wiring) subsystem The horizontal (wiring) subsystem consists of information sockets, cables or optical cables from information sockets to floor wiring equipment, floor wiring equipment and jumpers. Information sockets are RJ-45 standard. The length of each data horizontal twisted pair should not exceed 90 meters. The horizontal twisted-pair wiring is led out from the information point in the room and distributed to the corresponding building wiring cabinet. The entire wiring is connected in a star topology. Its laying adopts PVC trunking installation.
- The management subsystem manages the wiring equipment, cables, information sockets and other facilities in the equipment room, junction room and work area, and identifies and records according to a certain mode, and meets the following requirements: 1) Large-scale wiring system Computers should be used for management, simple wiring systems should be managed according to drawings and data, and records should be accurate, updated in time, and easy to consult. 2) Each cable, optical cable, wiring equipment, termination point, installation channel and installation space should be given a unique mark. 3) Wiring equipment, cables, information sockets and other hardware shall be provided with signs that are not easy to fall off and wear, and shall have detailed written records and drawings. 4) Both ends of the cable and optical cable should be marked with the same number.
- Equipment room subsystem The main equipment room (computer center room) of the entire building is mainly used for main wiring cabinets, network servers, switches and other network equipment. Considering the height and width of the building, distribution line rooms are set up between floors. In order to ensure the safety and reliability of the system, all wiring equipment and network equipment must be placed in the cabinet. Environmental requirements for the equipment room (computer room): 1) Temperature and humidity requirements According to the temperature and humidity requirements of the relevant equipment and components of the integrated wiring system, the equipment room should be implemented at level B. That is, the temperature is 12 to 30 degrees Celsius, the relative humidity is 35% to 70%, and the temperature change rate is less than 10 degrees per hour. 2) Factors such as heat insulation, dust prevention, fire prevention and anti-static requirements will have a serious impact on the performance and safety of computer systems. aspects should be considered. It is recommended to use anti-static raised floor for the floor, fire-resistant paint or metal-plastic aluminum plate for the wall, and metal ceiling for the ceiling. 3) The lighting requirements should be 0.8m away from the ground, and the illuminance should not be lower than 200Lx. 4) Power supply and distribution requirements The power supply between the equipment should meet the following requirements: frequency: 50Hz; voltage: 380V/220V; it is recommended to provide an independent power supply.
- (Vertical) trunk line subsystem The trunk line system refers to the cables from the main distribution room to the floor distribution room. Since there is no additional floor distribution room in this integrated wiring system, the design of the vertical trunk line subsystem is not considered.
- Building group subsystem The building group subsystem extends the cables in one building to the communication equipment and devices in other buildings in the building group. It is part of the entire wiring system (including transmission media) and supports the hardware needed to provide communication facilities between buildings, including copper wires, optical cables, etc.
- Requirements for the building of the computer room 1) Clear height of the house: 3.0 meters. 2) The ground of the building adopts movable anti-static floor (600x600mm), and its height from the ground is 300mm. 3) The top surface of the building adopts T-shaped bright aluminum alloy dragon frame and microporous aluminum ceiling (600x600mm) suspended ceiling. The height of the suspended ceiling is 3.0 meters from the movable anti-static floor. 4) The fresh air supply and exhaust of the central computer room adopts the method of ventilation fan. The reserved ventilation fan holes are installed at a height of 3.5 meters from the ground.
- Requirements for the working environment of the computer room
1) The temperature, humidity and air dust concentration require that the temperature and humidity in the room when the machine is turned on should meet the requirements of the following table: Project A-level B-level summer and winter year-round temperature (℃) 23±2 20±2 18-28 relative humidity ( %) 45-65 40-70 Temperature change rate (℃/h) <5 <10 When shutdown, the temperature and humidity in the room should meet the requirements of the following table: Item A-level B-level temperature (℃) 5-35 5-35 relative Humidity (%) 40-70 20-80 Temperature change rate (°C/h) <5<10 The temperature and humidity in the host room should be A-level when starting up, and the basic work room can be A and B-level according to equipment requirements. , and other auxiliary rooms should be determined according to the process requirements; the dust concentration in the air in the main room should be tested under static conditions, and the number of dust particles ≧ 0.5 μm per liter of air should be less than 18,000.
2) Noise, electromagnetic interference, vibration and noise in the static computer room should be less than 68dB(A) when measured at the operator’s position when the computer system is shut down; radio wave interference affects the stability of many electronic devices. Computer work belongs to weak and small signals and is extremely sensitive to interference. Therefore, necessary anti-interference treatment should be done-grounding or shielding, so that the radio wave interference field strength in the working environment should be lower than 126dB when the frequency is 0.15-1000MHz; The working environment should prevent permanent magnetic field or electromagnetic field interference, and its value should not be less than 800A/m. For this reason, the distance between the placement of computers and other equipment and high-voltage equipment such as substations should be kept at least 5M; the static leakage resistance of the ground and work surface of the main computer room should meet the requirements of the national standard “Technical Conditions for Raised Floors for Computer Computer Rooms”; The electrostatic potential of the inner insulator should not exceed 1kV.
3) The grounding of the computer room is based on the national standard 2887-89 “Technical Requirements for Grounding of Computer Stations”, which stipulates that the computer room should adopt the following four grounding methods: grounding for AC work, the grounding resistance should not be greater than 4Ω; grounding for safety protection, the grounding resistance should not Greater than 4Ω; DC work grounding can be divided into two types: DC ground suspension and DC ground directly connected to the earth. From the perspective of safety, the DC ground should be directly connected to the earth; lightning protection grounding, the grounding resistance should not exceed 10Ω. In the central computer room, the AC working ground, safety protection grounding, DC working grounding and lightning protection grounding share a set of grounding devices, and its grounding resistance is less than 1Ω.
4) Fire alarm and fire extinguishing system in the computer room. The computer room is equipped with an automatic fire alarm system; automatic fire detectors are set on the ceiling of the computer room, and the uniform distribution method is adopted. The protection area of each detector is 10-15 square meters; automatic fire detectors Use smoke detectors; according to the situation of the computer center, the fire extinguishing system in the computer room is equipped with a fixed fire extinguishing system of carbon dioxide or halogenated alkane.
5) Ventilation requirements In order to ensure that the fresh air in the central computer room is continuously replenished and the old air is continuously discharged to the outside, it is necessary to set up a ventilation fan in the central computer room.
6) Consideration of maintenance power supply According to relevant requirements, each room of the central computer room and the wiring room of each building should be equipped with AC 220v power sockets for maintenance. The installation height of the power socket is 300mm from the movable anti-static floor.
- System shielding and grounding 1) Shielding effect When there is electromagnetic interference in the surrounding environment of the integrated wiring system, shielding measures should be adopted to suppress electromagnetic interference. The cable is both the main generator and the main receiver of the cable trunk. As a generator, it radiates electromagnetic noise fields into space; sensitive televisions, computers, communication systems and data systems pass through their antennas, interconnects and power supplies. Lines receive this electromagnetic noise. The most basic purpose of using a shielding system is to ensure the transmission performance of the wiring system in an interference environment. The interference here includes two parts: reducing electromagnetic radiation, that is, reducing the radiated energy of the wiring system itself. And improve the ability to resist external electromagnetic interference. Cables with individually shielded pairs also have the ability to reduce pair-to-pair crosstalk. In order to eliminate interference, in addition to requiring the shielding layer to be provided with discontinuous points, it is also required that the shielding system must achieve a complete continuous 360-degree complete shielding. A complete shielding system requires shielding everywhere. First, the shielding at any point cannot meet the requirements, which will inevitably affect the overall transmission performance of the system. For a ground wire and a point-to-point connection, this requirement is difficult to achieve. Because of the information jacks, jumper wires, etc. It is difficult to shield, so shielding can not completely eliminate electromagnetic interference. In addition, the voltage difference between the ground points of the shielding layer can cause ground noise, such as excessive ground resistance, unbalanced ground potential, etc. This creates a potential difference between two points in the transmission system, which in turn creates a current on the metal shield. At this time, the shield itself has become a largest source of interference, resulting in its performance far less than the unshielded twisted pair. For the shielding system, it is not enough to have a layer of metal shielding layer. More importantly, it is necessary to have a correct and good grounding system to effectively introduce the interference to the ground, so as to ensure the safe and reliable transmission of signals in the shielding system. . 2) The type of grounding The grounding of the integrated wiring system should be considered together with the active equipment grounding system placed between its equipment and wiring rooms. The grounding system that meets the requirements of active equipment must also meet the grounding requirements of the integrated wiring system. Grounding is divided into DC working grounding, AC working grounding, safety protection grounding, lightning protection grounding, anti-static grounding and shielding grounding. In the grounding system, the grounding resistance is used to indicate the quality of the combination with the earth. The grounding resistance value is stipulated in the “Technical Requirements for Calculating Station Grounding” as follows: DC working grounding resistance should not be greater than 4Ω; AC working grounding resistance should not be greater than 4Ω; safety protection grounding resistance should not be greater than 4Ω; lightning protection grounding resistance should not be greater than 10Ω. The grounding resistance of the integrated grounding should not be greater than 1Ω. 3) The grounding of the wiring cabinet requires that the shielding layers of all shielded wires should be well grounded. The shielding layer should be connected to the grounding terminal of the floor wiring cabinet first, and the grounding terminal of the wiring frame on each floor should be connected to the grounding device in the wiring room. . The DC resistance of the grounding conductor from the building patch panel to the grounding device shall not exceed 1Ω and be permanently connected. 4) The grounding wire is required to be within 30 meters from the grounding body (from a suitable grounding point), and the grounding wire should be a multi-strand copper core wire with a diameter of 4 mm and an insulating sheath. If the distance from the grounding body exceeds 30 meters, the reference table for the diameter of the grounding wire is as follows: Distance (m) Wire diameter (mm) ≤ 30 4.030-48 4.548-76 5.676-106 6.2106-122 6.7122-150 8.0151-300 9.8 Wiring room Each patch panel must be reliably grounded to the ground bar of the patch panel (cabinet), the ground wire should not be less than 2.5 mm2, and the grounding resistance should be less than 1Ω.
- System test 1) Copper cable test performs a basic connection test (Basic Link Test) for each CAT5E information port, and the test items include: the information port in the work area and the connector work area to the horizontal line in the telecommunications room During the test of the patch panel interface, all the following parameters must meet the standards set by EIA/TIA 568A TSB 67: line connection diagram (wiremap) correct horizontal twisted pair length (length) <90m line attenuation (Attenuation) <23.2 dB near-end crosstalk (Near End Cross-Talk / NEXT)>24dB 2) Optical cable test Test standard: The test of optical cable transmission performance can refer to GB/T 8401. (1) Optical attenuation Whether it is a horizontal wiring subsystem, a building backbone wiring subsystem or a building group backbone wiring subsystem, the optical attenuation of each fiber in the cable should not exceed the specified value in the table below. Optical attenuation of each subsystem of optical cable wiring: Type Single-mode optical attenuation (dB) 1310nm Single-mode optical attenuation (dB) (1550nm) Multi-mode optical attenuation (dB) (850nm) Multi-mode optical attenuation (dB) 1300nm Flat wiring (100m) 2.2 2.2 2.5 2.2 Building wiring (500m) 2.7 2.7 3.9 2.6 Building group wiring (1500m) 3.6 3.6 7.4 3.6 (2) Whole-course optical attenuation In the optical cable wiring link composed of several subsystems, at the working wavelength point, each core fiber The full range of light attenuation should not exceed 11dB. The above test aspects are performed on all twisted pair cables connected from the distribution frame to the data network equipment. During the test, if any information port fails to pass the test, it needs to be checked, repaired or replaced until all of them pass the test. When the entire wiring project is completed, all the test reports will be handed over to the user together with other documents as records.