Abstract: The structured cabling two advantages, combined with the actual building all weak system, with the development and instability only telephone system and computer network systems.
As for the other weak systems, such as automatic fire alarm system, security surveillance systems, broadcast systems,glue stick cable television systems, equipment, with high fixed root, and the general location will not move, with a fixed structure for these systems The equipment is chosen, the possibility and necessity of frequent replacement are low.
Especially for modern intelligent building design of office buildings of the weak, the use of structured cabling systems have become common, but there are currently two views (or practice). One is the idea that all of the weak systems are built on structured cabling platforms are erected, that is, instead of using structured cabling wiring all of the traditional weak; the other one claims the computer network cabling, telephone wiring into the structured cabling, while the other weak systems still use its unique tradition of wiring.glue gun What kind of wiring to be more reasonable, should be combined with specific projects, programs from the use of advanced, reasonable, comprehensive consideration of economic and other aspects can only reach a conclusion.
First, the intelligent building weak solution to the basic ideas.
Let us first analyze the advantages of structured cabling. First, the structured cabling using standardized cables and then plug the module, very easy on each floor and information point between the floor management, making the office relocation and other factors due to the large number of terminal equipment, telephones shift, you Just pull the plug, insert a new position, and then do the electronic equipment within a process or just make some jumper changes on the software, you can back into use. Unlike the traditional route, as there is no uniform standard, when the device needs to shift, it will bring a lot of management is not convenient or need to re-wiring, and construction equipment will cause greater damage to speech. Use of structured cabling advantage of this second extension wiring capacity, because for five categories of unshielded twisted-pair can provide the information transmission capacity of 155Mbps, in addition to a variety of networks to meet current needs, but also to meet future development.
According to the structured cabling of the two advantages, combined with the actual building all weak system, with the development and instability only telephone system and computer network systems. As for the other weak systems, such as automatic fire alarm system, security surveillance systems, broadcast systems, cable television systems, equipment, with high fixed root, and the general location will not move, with a fixed structure for these systems The equipment is chosen, the possibility and necessity of frequent replacement are low. Based on the above, we generally weak design in the telephone system and computer network wiring systems into unified structured cabling, and other weak systems to maintain relative independence, is still using the traditional wiring methods.
However, the use of these methods there are other reasons: the majority of electronic equipment manufacturers, such as the current systems and structured cabling systems are not compatible. To make these weak systems in structured cabling platforms, you must increase the conversion equipment. Such as security camera monitoring system, the output of the video signal is usually coaxial cable, if incorporated into the structured cabling system, the need to increase the signal conversion equipment at both ends of lines, shown in Figure 1. Obviously, this cumbersome and uneconomical.
Second, the integrated wiring problems in the application:
According to the application of practice for some time, we found that the existing cabling products. Three, five categories of unshielded twisted-pair cross-section are 0.5mm2 (AWG AWG24), with the support of the patch panel, outlet seat can only apply to cross-section of 0.5mm2 cable. Therefore, it supports the following several weak subsystem, there is limited or inadequate.
1. Broadcasting System (PAS).
According to China's electrical specifications, general operating voltage of the electrical equipment 220/380V (exchange of 50Hz), 24V rms ac signal identified as the following weak signal.
In broadcast systems, such as the use of constant pressure output, line voltage can be divided into 70V, 100V, 120V third gear. Therefore, mining in the broadcast cabling system, cable will have over-voltage, long-term use will adversely affect the life of the cable, the other, the broadcasting system of lines with a line section is generally 1.0 ~ 2.5mm2, not shielded twisted-pair Only the core section of the line wire 0.5mm2, very different.
2. Fire alarm and control system (FAS).
According to China's existing automatic fire alarm system design specification: automatic fire alarm system wire signal transmission line section, pipes laid through the insulation of wires not less than 1.0mm2; trunking installation of insulated wire of not less than 0.75 mm2. As integrated unshielded twisted pair cabling system is its cross-sectional area of 0.5mm2 obviously does not meet the automatic fire alarm system design specifications. Also in the bus system of fire alarm systems, power lines and control lines and more use of 1.5 ~ 2.5mm2 conductors, integrated wiring system can not meet the requirements.
Of particular note is: our current Fire Code requires all fire signal lines, communication lines are not laid condominium and non-fire line. Support cabling products and thus to use the fire alarm and control system, must first obtain a license the local fire department.
3. Master Antenna Television System (CATV).
CATV cabling products used are generally used to support fiber, so in line amplifier, splitter, tap the two ends of the adapter must be installed, which will undoubtedly increase in investment, and increased by intermediate links, the system also reduces the reliability of the.
Described above cabling system to support the weak systems in our country there are still some problems, it is not to say that the structured cabling system can not support all these weak system? The answer is no. For a demanding intelligent buildings, and access to concessions in the specification allows for the premise, we can use fiber optic cabling and a variety of products, the number of unshielded twisted pair cables support computer networks and telephone communications systems, with the same support the CATV coaxial cable, and CCTV (surveillance TV, using cross-section of 1.0 ~ 1.5mm2 the special orders of unshielded twisted pair supports FAS, PAS).
Third, the concluding remarks.
In summary, the current intelligent building, some weak subsystems can not be fully integrated within the structured cabling. Advise the relevant units as soon as possible and to produce to meet a variety of different diameter and signal transmission requirements of the integrated wiring products, so that all systems are weak structured cabling into the goal can be achieved.