Several questions about structured Integrated Wiring System

As the pace of social informatization accelerates, people's concepts and requirements for modern buildings have also changed. The emergence of smart buildings has injected a new concept into traditional buildings, it has become the development direction of modern buildings, and the structured Integrated Wiring System is the basis and prerequisite for building intelligence.

I. Relationship between smart buildings and integrated wiring systems

Intelligent Building is an integrated system integrating the building automation system BAS, Communication Automation System CAS, and office automation system OAS.

BAS is an integrated system composed of multiple building control subsystems with the central control system as the core, it mainly includes power supply, air conditioning, lighting, fire fighting, elevator, water supply and drainage, alarm, LED/VGA display, smart card access control management, parking lot management, TV monitoring and other equipment control subsystems.

CAS is the "central nervous system" of the computer and communication systems in the building. It includes a communication network with a program-controlled switch as the core, a multi-function telephone, fax, and various types of terminals as the main equipment, as well as lan, workstation in the building, backbone communication network of high-speed broadband, and network interface equipment connected to the public network.

OAS is mainly composed of computer, multi-function telephone, fax machine, various types of terminals, audio and video storage devices and other office equipment plus the corresponding software, provides office functions such as text processing, document management, electronic accounting, email, electronic data exchange, electronic blackboard, and conference and television. To implement these functions, a smart building must implement structured and integrated cabling of the building. The structured Integrated Wiring System aims at the current and future cabling requirements of the smart building system, and uniformly plans and designs the wiring between the building and the building, in this way, the BAS, OAS, and CAS of the smart building can be organically combined to form an intelligent system of the building. It is obvious that structured cabling systems are integrated systems in multiple fields, including construction, computer, communication, and automatic control technology.

II,Several Basic Problems of structured Integrated Wiring System uses various twisted pair wires, optical fiber transmission media, as well as various adapters, information sockets, distribution frames and other equipment to construct high-speed information channels in the building group.

(1) Main Features

1. comprehensiveness: it can be used as a transmission medium for voice, data, images and control signals.
2. modularization: the modular design of independent subsystems facilitates cabling expansion and reconfiguration.
3. Flexibility: Any information point can connect to different types of devices.
4. Openness: network products of any manufacturer are supported.

(2) standardization issues

In 1990s, Generic Cabling Standards were issued.
It greatly simplifies the complexity of engineering design and increases the applicability. These standards include:

EIA \ TIA 568, ISO \ IEC 11801, TSB67
EMC Drirective,

Standard for structured and integrated cabling of buildings in China

(3) Basic system composition and function division

Structured cabling systems can be divided into the following six subsystems based on their functions:
1. sub-systems between devices: configure a distribution frame to connect public networks, management subsystems, and sub-systems of Buildings
System.
2. Main subsystems: cables are used to connect subsystems between devices and management subsystems at various layers.
3. Management Subsystem
The jumper between the cable and the vertical trunk subsystem.
4. horizontal subsystem: use cables to bring the workspace subsystem to the management subsystem.
5. Work subsystem: connect to user devices through standard information interfaces.
6. Building Group Management Subsystem: connect the sub-systems of various buildings with cables.

(4) several common types of structured integrated wiring systems

There are many types of structured cabling systems in the world, most of which are communication equipment manufacturers and computer equipment manufacturers, currently, AT&T, alcatel ibm, NT, and Digital products are widely used.

1. AT&T sans IMAX has three categories, five categories, cat5e UTP unshielded twisted pair cable, information socket, adapter, photoelectric distribution frame and other products, can support 10 Mbps, 155 Mbps (STM-1 level) 622 Mbps (STM-4 level) end-to-end application, UTP cable characteristic impedance is 100, using unshielded twisted pair balanced characteristics for electromagnetic interference protection. In addition, the AT&T megaimax series also include 625/125 multimode optical fiber with a nominal wavelength of nm and 1300nm single-mode optical fiber, supporting higher-speed applications. AT&T's replicimax is the first product to enter the Chinese market and use the most frequently.

2. alcatel acs uses shielded twisted pair wires (FTP) with a characteristic impedance of 120. The shielding layer and twisted pair wires are used together to defend against electromagnetic interference. The anti-electromagnetic interference performance is good, and the product series are complete, easy installation and promising market prospects. There are still many structured Integrated Wiring products.

Iii. Several Problems in Engineering Design

(1) Design Consideration of the restriction on the valid length of cabling for traditional communication wiring and the control line of building management systems such as telephone, fax, and telex, the length of building wiring is basically unrestricted, however, for computer networks used for data communication, there is a high requirement on the wiring length, that is, the length of the twisted pair wires between network devices cannot exceed 100 meters, this increases the complexity of the Structured Cabling System Design for large buildings. The following principles can be taken into consideration during design.

The first is to ensure that the cable length between systems does not exceed 100 meters. This mainly takes into account that the computer network system application can increase the allowable cable length (one level in each level, 100 metres away) between network devices through the Cascade Method of the network Hub. Generally, it can be 5 ~ 6 levels of Hub cascade, so that the allowed distance between network devices will be greatly extended.

The second is that deploying optical cables can also solve the problem of effective cabling length restrictions.

(2) design considerations for deploying Optical Cables

When the network system in the building needs to use optical fiber, such as the ATM Backbone Network and FDDI network, the optical cable design should be considered when the network is connected to a Hub with optical interfaces, a network switch with optical interfaces, and a host with optical interfaces. In addition, when the wiring range of high-rise buildings is limited by the valid length of cables, you can also consider deploying optical cables. A multi-core optical fiber cable can be deployed in the subsystem of the Building Group and the main subsystem in the building. The optical distribution frame can be set in the subsystem and management subsystem of the equipment room. If you want to support the application of Fiber-to-household FTTH and fiber-to-desktop FTTD, then, the optical fiber cloth is placed in the room to be reached and the optical fiber distribution unit is mounted.

(3) Capacity Design Considerations of main subsystems

When a twisted pair cable is used as the trunk, if the horizontal subsystem and the trunk subsystem are wired at, that is, the logarithm (or the number of corresponding information ports) of the structured integrated cabling system of the horizontal subsystem line) similar to the trunk subsystem line logarithm, the information port of each subsystem in the work zone can correspond to the eight-core line pairs on the trunk cable, but this wiring is not economical. The general algorithm is that for information ports for communications such as telephone, fax, and telex, and information ports for control lines of building control systems, the power distribution coefficient is ~ -For information ports and wiring coefficients for computer communications ~ Between. The specific coefficient is determined by the user's actual usage, future expansion plan, and the user's economic strength. Generally, the distribution coefficient of the port used for computer communication is lower. In an image, an 8-core twisted pair wire on the trunk can be connected to the Hub, and the Hub can carry multiple computers, if the Hub is cascaded, more computers can be taken.

When using optical cables as the trunk, the common practice is to use multiple 4-core or 6-core optical cables to connect the subsystems between devices to various management subsystems or some management subsystems, when a computer network is connected using optical fiber, a 10-core optical fiber is used for a 10-BASE-T, 100Base-T, and an atm cidr block, and a 4-core optical fiber is used for FDDI. Therefore, it is determined that the number of cores of the optical fiber can meet the usage requirements and leave a certain number of spare cores. Of course, the specific connection method between the core number of optical fiber cables and optical fiber cables should be designed to take into account the specific usage, expansion plan and economic affordability.

(4) design considerations for video signal cabling

According to the design philosophy of the structured integrated cabling system, various information (including voice, data, and images) can be integrated and transmitted through a structured integrated cabling system, to obtain the maximum flexibility of information transmission. For example, closed-circuit television monitoring signals and CATV signals can be transmitted using RF cables or Cables Using a structured Integrated Wiring System (the adapter must be added, of course). These applications are technically not a problem, such as AT&T Power Sum system (cat5e standard) can support up to 622 Mbps (STM-4 level) rate, with 384A adapter and mp100 module and other accessories can provide m TV bandwidth, about 70 TV channels can be transferred. However, in a specific engineering design, the information wiring integrated should be determined by the Technical Economy, without increasing investment for integration.

Iv. Connection Between the Structured Cabling System of the building and the Access Network

The access network technology includes the narrowband access network technology for traditional copper cables that provide POTS services and broadband access networks such as HDSL, ADSL, HFCs, FTTB, and FTTC.

For a variety of narrowband and broadband applications that require only copper cables as access, such as telephone, fax, 160Kbps N-ISDN, 384Kbps video conferencing systems, HDSL, ADSL, and other applications, the structured integrated cabling system in the building naturally provides better transmission quality than copper cables. For optical fiber network access, you can connect to the optical fiber network in the building of the structured Integrated Wiring System to achieve the results of optical fiber to the household and optical fiber to the desktop. For HFCs, coaxial cables can also be replaced by twisted-pair cables of structured integrated cabling systems, as discussed in the previous section on cabling of video signals, it is technically feasible to transmit these videos and RF signals over twisted pair wires through adapters, mainly due to economic costs.

V,To strengthen the standardized management of the design of structured cabling systems, structured cabling systems have just developed in China in recent years and started late. From the perspective of structural Integrated Wiring System Design and civil engineering cooperation, the architectural design department does not have enough knowledge and attention on this technology. For the structured Integrated Wiring Design, the size and location of sub-systems used between devices, and the reserved and used area and location of the main sub-system's cabling holes or shafts, whether the level subsystem is pre-embedded, hidden pipe, shed, information port of the subsystem in the work zone, and cabling channels between subsystems, most of them are insufficient considerations (most of them are designed based on the traditional Weak Current System), which makes it difficult to put the space that should be reserved and the pipeline that should be reserved in place during civil construction, even in the masonry and decoration phase is not yet in place, which will lead to an increase in the difficulty of wiring construction and construction, often damage the building structure and affect the appearance of the results.

From the perspective of the level and quality of Cabling Design, the main units currently engaged in structural integrated Cabling Design are the weak current construction design departments and computer companies, the problem exposed is that the weak current architecture design department does not know much about computer network technology, leading to unreasonable wiring system design. Computer companies are not familiar with Weak Current majors such as civil engineering and communication and automatic control, and they also consider design from the perspective of product sales, resulting in unsatisfactory wiring design. To change the above situation, we should determine an Industry Management Department to strengthen the qualification management for the structural Integrated Wiring System Design Unit, it also strengthens the implementation of the engineering design specifications and corresponding technical standards for the structured cabling system of buildings and buildings, to ensure that the market for structured cabling systems can develop in a healthy and orderly manner.

Vi. Conclusion

The construction of structured Integrated Wiring System has been developing very rapidly in the past two years, and new standards and improved products will be continuously launched. It is hoped that the design department will keep track of new technologies and study new product applications, in-depth technical and economic discussions bring the application of structured cabling systems to a new climax.