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1. Documents related to unpacking inspection include equipment list, unpacking inspection list, unpacking inspection report and goods problem feedback form.
2. The tools for unpacking inspection mainly include a crowbar spanner, a hammer and a vise forklift.
3. The main contents of hardware assembly and connection include unpacking inspection, hardware assembly, power connection, cable installation and label making, cable laying and hardware acceptance.
4. There are two basic ways to fix the rack: one is to install it on the base, and the other is to sit on the ground.
5. The common power supplies for communication equipment are DC power supply and AC power supply. According to the voltage level, AC power supply includes 220V and 380V, and DC power supply includes -48V, +24 and storage battery.
6. Communication power supply system is mainly composed of four functional modules: AC power distribution unit, DC power distribution unit, rectifier module and monitoring unit.
7. There are three ways to install the power cabinet, namely, direct placement, sitting installation and bracket installation.
8. The combined power supply and storage battery together form an uninterruptible power supply system.
9, twisted pair according to the function is divided into unshielded twisted pair and shielded twisted pair.
10, the current wiring standards are T568A and T568B, which are commonly used. T568B The wiring sequence from 1-8 is orange, white, orange, green, white, blue, white, green, brown, white and brown. T568A The sequence from 1-8 is green, white, green, orange, white, blue, white, orange, brown, white and brown.
1 1, and the line sequence at both ends of the parallel line consists of T568B and T568B or T568A and T568A; The intersection line consists of T568A and T568B, T568B and T56A; Generally speaking, crossover cables are used for interconnection between devices of the same type, and straight-through network cables are used for interconnection between devices of different types.
12.RJ45 is used for network cables, RJ 1 1 is used for telephone lines, and BNC is used for coaxial cable connectors.
13. The preparation process before hardware installation includes tool data preparation, material inspection, engineering pre-installation and the second environmental acceptance.
14, broadband cable is the most widely used in communication, that is, 75 ohm coaxial cable.
15. There are many factors that affect the fusion loss of optical fiber, among which the internal factors are inconsistent fiber mode field diameters, mismatched fiber core diameters of two optical fibers, noncircular cross-section of fiber core and poor concentricity of fiber core and cladding.
16. Optical fiber connection point loss measuring instruments include optical time domain reflectometer (OTDR), and common optical fiber connectors include FC type and SC type.
The feeder windows produced by 17 and ZTE have 4 holes, 6 holes, 9 holes and 12 holes.
18. After the antenna feeder system is installed, the standing wave ratio of each feeder must be tested, and the standing wave ratio should be less than 1.5, otherwise it will be unqualified.
19. During the construction period, the project acceptance includes preliminary inspection, trial operation and final inspection.
20. When cables are bundled into bundles, the spacing between cable ties should be 3-4 times the diameter of the cable bundle.
Second, short answer questions
★ 1. What are the main contents of hardware installation? Hardware installation is the process of combining communication components into a running system in a certain order.
① unpacking inspection ② hardware assembly and connection ③ power supply installation ④ cable and label making ⑤ cable laying ⑤ antenna feed system installation ⑦ hardware acceptance.
2. What are the precautions for unpacking inspection? (1) Don't perform rough construction during operation, and pay attention to skills to prevent equipment from being damaged. ② Unpackaged equipment should be kept in a dry and safe room. (3) If the work cannot be started temporarily, the equipment shall be repackaged and stored after the goods are unpacked and inspected. (4) When the equipment is brought from a low-temperature dry place to a high-temperature and humid place, it must wait at least 30 minutes before unpacking. Otherwise, it is easy to cause moisture to condense on the surface of the equipment and damage the equipment. ⑤ The equipment shall be placed in an orderly way, not at will, otherwise it will affect the construction and installation.
3. What are the precautions for hardware assembly and connection? (1) When fixing equipment, ensure that all equipment is in a straight line and insulated from the ground. During the installation process, there may be tapping equipment to correct the position of the equipment. Rubber hammer is generally used, and care shall be taken not to damage the appearance of the equipment; ② Equipment arrangement is generally from low to high or from high to low, and from important to secondary in the case of consistent height. For example, there are three kinds of cabinets: main equipment, server cabinet, power cabinet and distribution frame. From left to right, there are power cabinet, main equipment, server cabinet and distribution frame in turn; (3) When climbing or working above the equipment, avoid stepping on cables and rack equipment, and fix your belongings firmly to avoid the danger of falling or colliding with the equipment; The top of the cabinet should be protected, and no engineering wastes such as metal chips can fall on the top of the cabinet. (4) After the equipment is assembled, it shall be fixed according to the pre-planned position, and the fixed connection between parallel cabinets and parallel groups shall be made; ⑤ The final inspection standard of hardware assembly is that it can run directly after power-on, and will not damage the equipment and cause accidents due to missing or wrong parts; ⑥ Hardware assembly requires a high degree of mastery of communication equipment, so besides being able to read drawings, it is also necessary to have a certain understanding of the hardware structure of the installed equipment.
4. Briefly describe the hardware connection inspection standard?
① Whether the hardware connection is carried out in strict accordance with the engineering design ② The vertical gap between cabinets is less than or equal to 3mm③ The distance between the front of one row of cabinets and the front of another row of cabinets is ≥ 1600mm, the distance between the side of cabinets and the wall is ≥800mm, the distance between the measuring surfaces is ≥ 1200 mm, and the computer room should have a channel with a width not less than 1m; ④ Seismic strengthening should meet the engineering design requirements; ⑤ Equipment equipped with insulation anchor; After installation, the frame and expansion bolts should be insulated; ⑤ Similar bolts should face in the same direction, and the front of equipment in the same frame should be in a straight line with an error of less than 5 mm; ; The gap between racks shall be less than or equal to 3mm; Similar racks are adjacent, the height deviation is less than 2 mm, and the vertical deviation of the cabinet should not be greater than 1‰ of the rack height. The horizontal deviation of the cabinet should not be greater than 1‰ of the rack height. Adjacent cabinets in the same row should be close together, and the gap should not exceed 3mm 8. The tops of cabinets with the same specifications should be in the same horizontal plane, and the deviation should not exceed 3 mm.. Cabinets in different rows should be aligned on one side of the main aisle with an error of not more than 5 mm, and the front faces of adjacent cabinets should be in a vertical plane without obvious unevenness. The length difference of exposed parts of fasteners with the same specifications should be less than 3 mm.
5. Briefly describe the installation steps of the rack base? ① Marking and punching; ② Mounting and fixing of base; ③ Fixing of frame; ④ Insulation test; ⑤ Installation of anti-static floor tray.
★6. Briefly describe the main contents of the electrical connection of the combined power supply system? Grounding wire connection (including protective grounding and working grounding); Connection of AC input line; Connection of DC output line; Electrical connection between battery pack and system; Connection of various detection, control and communication cables in the rack; Monitor the electrical connection of the line (when networking is required).
★7. Briefly describe the main contents of joint power system debugging? Power system debugging mainly includes: check before starting; AC distribution unit debugging; Rectifier debugging; Monitoring unit debugging; Put the battery into operation; Loading loading equipment; Adjustment and measurement of the whole machine.
★8. Briefly describe the process of network cable production? (1) Use the cutting edge of the wire cutter to cut the wire with appropriate length. (2) Use the wire cutting edge of wire cutters to cut suitable long filler wires. (3) After peeling off the outer sheath, you can see 4 pairs of 8-core twisted pair cables. Disassemble 4 pairs of 8 thin wires one by one, straighten them, and arrange them neatly according to the specified line order. (4) Straighten the thread as far as possible, squeeze it and straighten it, and then cut the thread end flat with the thread pressing pliers. ⑤ Insert eight wires simultaneously along the eight trunking of RJ-45 head until the top of the trunking. ⑥ After confirming that all wires have reached the bit line sequence correctly, you can clamp RJ-45 head with wire pressing, and press all protruding pins into the merging head.
9. Briefly describe the error detection method of network cable test? At this time, it is best to press the crystal heads at both ends with wire clamps and then measure them. If the fault still exists, check whether the arrangement order of the core wires at both ends is the same. If not, cut off one end and re-make the crystal head according to the arrangement order of the core wires at the other end. If the fault still exists, it must be a poor contact of the corresponding core wire. At this time, there is no way out, so we have to cut off one end, redo a crystal head in the order of the core wire at the other end, and then measure it. If the fault disappears, we don't have to redo the crystal head at the other end, otherwise we have to cut off the original crystal head at the other end and redo it. Until all test indicators flash.
10, briefly describe the manufacturing process of coaxial cable?
① Peel off the skin with wire stripper ② Straighten the wire wound on the inner insulation layer and peel off the tin foil covered on the inner insulation layer. You can see the white inner insulation layer. (3) Strip the inner insulation layer with wire stripping pliers, and the length shall be subject to welding. At this time, you can see that the copper core of the cable is in the inner conductor. (4) Insert the cable into the coaxial cable head, insert the small copper core in the middle into the groove of the cable head, and weld the thin copper core with the groove with solder wire. Note that the welding must not cause virtual welding at this time, otherwise the cable may be unsuccessful. ⑤ Wrap a copper net around the outer side of the cable head, tighten the sleeve, and finally put on a heat-shrinkable sleeve, iron and soften the heat-shrinkable sleeve with an electric soldering iron, and cover the tail of the cable head.
1 1. How to distinguish single-mode fiber from multimode fiber?
Multimode optical fiber: The central glass core is thick (50 or 62.5μm), which can transmit multiple modes of light. However, its large intermodal dispersion limits the frequency of transmitting digital signals, and it will become more serious with the increase of distance. Therefore, the transmission distance of multimode fiber is relatively short, generally only a few kilometers.
Single-mode fiber: The glass core in the center is thin (the core diameter is generally 9 or 10μm) and can only transmit one mode of light. Therefore, its intermodal dispersion is very small, which is suitable for long-distance communication, but its dispersion plays a major role. Therefore, single-mode fiber requires high spectral width and stability of light source, that is, narrow spectral width and good stability.
12, briefly describe the characteristics and classification of optical fiber?
Optical fiber characteristics: wide bandwidth, low loss, shielding electromagnetic radiation, light weight, safety and confidentiality.
Classification of optical fiber: ① According to the transmission mode of light in optical fiber, it can be divided into single-mode optical fiber and multimode optical fiber. ② According to the optimal transmission frequency window, it can be divided into conventional single-mode fiber and dispersion-shifted single-mode fiber. ③ According to the refractive index distribution, it can be divided into two types: abrupt fiber and graded fiber.
★ 13. What are the factors that affect the fusion loss of optical fiber? There are two internal factors and external factors in optical fiber. ① Intrinsic factors of optical fiber refer to the factors of optical fiber itself, which mainly include four points: (1) fiber mode field diameter is inconsistent; (2) The core diameters of the two optical fibers are not matched; (3) The cross section of the fiber core is not circular; (4) The concentricity of core and cladding is not good. ② The external factor is the connection technology.
★ 14. What are the measures to reduce the fusion loss of optical fiber? ① Try to use the same batch of high-quality brand-name bare optical fibers on one line. (2) Set up optical cables as required. ③ Select experienced and trained optical fiber splicing personnel for splicing. (4) Connecting optical cables must be carried out in a clean environment. ⑤ Select high-precision optical fiber end face cutter and prepare optical fiber end face.
⑥ Correct use of welding machine.
15, brief description of cable binding specification?
(1) Laying walkway cables must be bundled, and the bundled cables should be close to each other, with straight and tidy appearance and even and reasonable bundling position. The height of the plane formed on the surface of the cable shall not exceed 5mm, and the difference of vertical air blowing performance formed on the surface of the cable shall not exceed 5 mm; (2) Cables in the trough can be laid without binding, and the cables in the trough should be as straight as possible without crossing. Cables should not overflow the channel, and plastic cards should be used to bind or fix cables in and out of the channel and cable bend. (3) Cables in cable channels without crossbars shall be bound. The binding process of optical cable pigtails in racks is good, and there is no squeezing feeling. The pigtails between racks should be protected by sleeves. (4) Whether the specification of steel wire buckle is appropriate. The larger the cross-sectional area of the cable bundle, the longer and wider the steel wire buckle used. Thread spacing is consistent, spacing is 300 mm.. ⑤ After the thread is buckled, the excess parts should be cut off and kept flush. The bent part of the cable can't be tied with a buckle. 6. Plug-in contact should be tight and firm, and the plug-in should be straight and not bent or bent. After cables and wiring are plugged in, the whole line should be completed to make the appearance straight and tidy. ⑦ The radial deformation of unit wire diameter length should not exceed 10 degree. ⑧ After similar cables are laid and plugged, the turning radius of the plugging angle should be consistent.
★ 16. Briefly describe the installation process of the antenna feed system?
Start → antenna installation → feeder window installation → feeder installation → lightning arrester installation → indoor jumper installation → standing wave ratio test → connector waterproof treatment → end.
17, briefly describe the installation process of the antenna?
18. What are the basic requirements for binding and fixing antenna jumpers? (1) Binding should be neat and beautiful, without crossing. ② Tie the antenna jumper with anti-ultraviolet tie. ③ The minimum bending radius of antenna jumper should be less than 20 times the radius of antenna jumper.
★ 19. About the paper feeder:
(1) What are the common feeder specifications?
7/8 main feeder, 5/4 main feeder and 1/2 jumper.
(2) Write the structure of the base station feeder.
Antenna jumper, tag, feeder, mine, top jumper.
(3) According to the length of antenna feeder, what are the combination schemes of main feeder and jumper? When the length is more than 20m and less than 80m, the combination of 1/2 jumper and 7/8 feeder shall be adopted. When the length exceeds 80m, use 1/2 jumper and 5/4 feeder.
(4) Briefly describe the basic workflow of feeder installation? P2 13 starts-determine the feeder route-make a connector at one end of the feeder-cut off the feeder-hoist the main feeder to the top of the tower-connect the main feeder with antenna jumper-make a connector at the other end of the feeder-lay and fix the main feeder-install the feeder grounding card.
(5) What are the laying principles and steps of the main feeder? Principle: ① The layout of indoor and indoor lead frames introduced from the feeder window should be neat, beautiful and without crossing. (2) there should be no cross when laying ladders along outdoor distribution frames and iron towers; ③ Know the route of feeder before laying; ④ The minimum bending radius of the main feeder should not be less than 20 times the radius of the main feeder; ⑤ Feeder card spacing: 1/2 feeder is equipped with a feeder card every meter, and 7/8 or 5/4 feeder is equipped with a feeder card every 1.5m; ⑤ The local wind speed is greater than 160km/h/.
Steps: ① Install the triple supply card; (2) preliminarily processing the feeder from the antenna to the room; ③ fix the main feeder from top to bottom; Clip it into the triple supply card and tighten it neatly; ④ Make an outdoor ladder from the roof along the room and fix the feeder with the triple feeder card.
(6) What are the grounding requirements of the main feeder?
① The feeder grounding card should be installed at least three places on the main feeder, namely, on the platform of the tower, where the main feeder leaves the tower and before the main feeder enters the room; ② The antenna system, antenna bracket and newly installed wiring rack installed on the roof should be welded with the lightning protection network of the building; ③ The outdoor wiring ladder of the main feeder entering the room from the roof along the wall should be grounded; (4) outdoor copper bar should be installed on the wall outside the feed window, and the best position is directly below the feed window or on the rain-proof wall of the roof feed well.
(7) What are the precautions for the main feeder to penetrate into the computer room? P22 1① Ensure that the feeder will not introduce rainwater into the machine room, and make a drip tank if necessary. ② Feeders enter the computer room through the feeder window, and the indoor and outdoor parts must be introduced through wire racks.
(8) Write out the connection and sealing steps of 1/2 jumper and feeder? ① Connect and tighten the antenna jumper with the main feeder connector. (2) Waterproof and sealed joints (1). After the joint is connected, wrap a layer of electrical insulating tape on the joint in the direction of tightening the joint. The winding length exceeds the joint tail 10 mm, and sufficient tension should be applied during winding. 2. When winding the waterproof self-adhesive tape, start from the lower part of the joint and fill the low-lying part with a small amount of adhesive tape. 3. In the winding process, the self-adhesive tape should be stretched to twice the length, and each joint should use 60 cm long waterproof tape, which needs to be wound three times. 4. The waterproof tape is wound layer by layer. Do not cut the tape during winding. The length of the adhesive tape should be about 20 mm beyond the feed head. 5。 After winding the waterproof self-adhesive tape, you need to hold it with both hands to ensure that the tape and the feeder/feeder are firmly bonded. 6. Wrap PVC tape outside the waterproof tape. When winding, the upper layer 1/2 is covered with the lower layer adhesive tape, and two layers are wound. The winding length of the tape should exceed the waterproof self-adhesive tape10mm ... 7. Hold the PVC tape and waterproof tape together with both hands again to ensure that the PVC tape and waterproof tape are firmly adhered. 8. After the above steps are completed, fix both ends of the replacement with anti-ultraviolet tape to prevent the tape from aging and falling off. )
(9) VSWR test of feeder of antenna feeder system failed. What aspects should I check?
Check the antenna feed system: ① Whether there is any problem in the installation of antenna feed connector; ② Whether there is a problem with the antenna; ③ Check whether the outer surface of the feeder is damaged and whether the curvature of the feeder is less than the allowable minimum bending radius;
Whether there is any problem in the installation of lightning arrester.
20. Briefly describe the workflow of communication engineering acceptance? P232 Initial Test Run Final Test
★2 1. What are the forms for communication engineering acceptance?
Input: preliminary inspection application report, preliminary inspection letter, first acceptance certificate, preliminary inspection and acceptance institution, acceptance test record (preliminary inspection) and trial operation description.
Outputs: project service satisfaction questionnaire, acceptance test record (final inspection), project memorandum, technical documents of project completion, handover list of equipment and main materials, project completion data, on-site training record, quality evaluation and general evaluation of project quality in acceptance stage, final inspection application report, final inspection and acceptance organization, memorandum of remaining problems in acceptance and final verification letter.