Construction of sks. SKS grounding system

SCS is a universal infrastructure information technology(IT), defining directions in the design of cabling systems based on end-user requirements. A modern company cannot do without e-mail, local, computer and telephone networks, without databases, without access to the Internet or ICQ. All this is necessary to solve current business problems and all this is the Information Technology (IT) infrastructure or SCS, the versatility of which is laid down during the design and is capable of influencing the efficiency of work in the future, expanding and “shrinking” according to business requirements and always remaining a reliable support for a stable development of any organization.

Represents cabling, implemented in accordance with certain standards. The main difference between SCS and LAN is its independence from applications that will be used subsequently, which allows it to support a wide range of applications. Compliance of SCS with standards makes it possible to integrate into a single information structure:

  • computer (LAN) and telephone network (TS);
  • security and fire alarm systems (OSS);
  • security video surveillance (SVS) and IP video surveillance;
  • access control system (ACS) and sound notification;
  • television and radio, etc.

Structured cabling system is a universal cabling system of a building (or complex of buildings), built according to the rules defined by international standards:

  • ISO/IEC 11801: 2002(E), Information Technology Generic Cabling for Customer Premises.
  • ANSI/TIA/EIA-568-B, Commercial Building Telecommunications Cabling Standard.

SCS can be built on the basis of many products from different manufacturers using two main signal transmission media- copper twisted pair and fiber optics.

The structured cabling system of SCS can be implemented both in a group of buildings and in a separate building. It can consist of three subsystems that can be connected into a network with a star topology.

Topology

SCS is cabling, implemented in accordance with certain standards. The main difference between SCS and LAN is its independence from applications that will be used subsequently, which allows it to support a wide range of applications.

Compliance of SCS with standards makes it possible to integrate a computer network, LAN, telephone network, security and fire alarm systems, security video surveillance and IP video surveillance into a single information structure; access control and sound warning system; television and radio, etc.

The service life of such infrastructure is immeasurably longer than that of individual network devices, and the greater the understanding of the need to invest in structured cabling and enterprise security systems, the greater the savings you can expect in the long term. The construction of the computer network itself may have several various topologies: star, common bus, tree or be looped and, for example, within the same building it differs into a horizontal component and a main one.

Horizontal cable system- a floor system of a building that connects telecommunications outlets in the workplace (Work Area - WA) with a horizontal cross-connection (Floor Distribution - FD) located in the telecommunications room. FD can be located on the same or adjacent floor.

Backbone cable system inside the building- cable system (CS) connecting each horizontal cross-connect (FD) inside one building with the main (Campus Distribution - CD) or building cross-connect (Building Distribution - BD).

Backbone cable system between buildings- a cable system connecting buildings in a group of buildings. Each external trunk cable runs from a main distribution center (CD) (usually located in the central building) to a distribution center (BD).

SCS design

When designing a SCS, we will ensure productive and efficient use of the workspace by optimizing its four main elements, namely: structure, systems, services and management, as well as the relationships between them.

One of the areas of our activity is carrying out a full range of works on the design, supply and installation of equipment for the creation of Data Processing Centers (DPC): low-current cable systems, uninterruptible power supply systems, monitoring systems and maintaining specified climatic conditions, network equipment, servers and data storage systems ; To create reliable security systems: video surveillance, fire alarms, access control and management, we use ready-made solutions for integration with IT systems, which allows us to optimize costs and expand the capabilities of existing equipment.

Installation of SCS

We use proven technologies, equipment and materials from certified manufacturers. Construction work We minimize installation of SCS and are focused on the final result; letters of gratitude and recommendations from Customers are the main indicator of our qualifications.

Company specialists LLC "EngineeringGroup" They will install SCS, test and, if required, certify the installed SCS equipment, issue a warranty card and help maintain and maintain your system in working order. We are sensitive to the Customer's wishes and always try to do a little more than he expects.

Advantages for the Customer when working with us

Why do they trust us?

Low prices. We offer really low prices, and even more so for a complex order or for repeat applications, because you work not with intermediaries! cost of the project when ordering installation work! The cost of equipment and consumables is much lower than that of competitors due to experience and sales volumes. We consider the first year of maintenance (TO-1 and TO-2) to be a guarantee and it is free for our Customers!
Design department. Our GUI department is the core of all creative endeavors necessary to create a modern, high-quality product. Designers are the first to take an individual approach to each developed object, perform quick and high-quality calculations, detailed elaboration of technical documentation, carry out “designer supervision” and support the adopted engineering solutions.
Freedom of choice. We are not associated with the supply of any specific equipment; we have our own warehouse and many different suppliers. We install equipment at sites only from those manufacturers whose equipment meets all client requirements for reliability, efficiency, safety and price. The engineering systems we install allow you to reduce your costs at the construction stage, during operation and when expanding the system in the future.
Full-time specialists. Our engineers and installers working on site work on a permanent basis; we carry out all work from installation to commissioning ourselves, without the help of random installation teams. Our engineers are not sellers of related services and additional work, but trained professionals focused on results.
Legality. Our activities are legally established; we are always ready to provide you with the necessary permits, approvals, licenses and certificates. The absence of intermediaries allows you to reduce the time it takes to make technical decisions and ultimately save your money.
Service center. Since 2009, we have been providing you with services for maintenance and repair of complex modern engineering systems, has diagnostic equipment, a stationary workshop, and its own warehouse for spare parts and replacement stock. The qualifications of our employees allow us to repair and put into operation almost any security system in the shortest possible time, and the mobility of our teams and the presence of several strongholds allow us to arrive at the site of an urgent repair within 2 hours in Moscow.
Individual approach for us it is sensitivity to the customer’s expectations, complete mutual understanding, reliability of cooperation, efficiency and achievement of a common goal. We strive for long-term and mutually beneficial cooperation.

What is SKS?

Structured cabling systems (SCS) are the basis for creating information infrastructure. By combining user workstations and equipment into a single infrastructure, SCS serves to transmit data, voice and other information. Various low-current building systems and telephone networks can be connected to it, the transmission medium of which uses unshielded or shielded twisted pair cable of categories 5e and 6, as well as fiber-optic cable. The task of SCS is to satisfy the needs of all potential users of the system for the entire life of the building without alteration or expansion of the cable network. Logically, SCS can be divided into the backbone cable subsystem of a territory or building complex, the backbone vertical subsystem of the building connecting its floors, and the horizontal subsystem of the floor - from the distribution point to the communication sockets at the workplace (see Figure 1).

It includes connecting cables (twisted pair, shielded or optical), patch panels (with mortise contacts or modular sockets), connectors, sockets, adapters. Mounting cabinets and racks, cable channels are usually not included in SCS, but are often supplied with it as a ready-made solution. The construction of SCS is based on the following basic principles:

VERSATILITY


The principle of universality lies in the use of standardized connectors for connecting any terminal equipment (computers, phones, sensors and any other devices that transmit signals over copper twisted pair) to the network. The connection to each connector of a four-pair copper cable ensures the use of any signal transmission protocol (computer data, telephony, alarm, etc.)

STRUCTURING THE HIERARCHY OF LEVELS


The SCS structure has clearly defined functional subsystems, for each of which the rules of physical construction, topology and methods of physically connecting lines are defined. The application of this principle simplifies network administration, facilitates maintenance, and allows you to increase the size of the network without restrictions, both quantitatively and structurally.

DIVISION INTO CATEGORIES


Sets are standardized within SKS electrical characteristics, which determine the capabilities of the system in terms of data transfer speed - the so-called data transfer categories. Knowing that the system corresponds to a certain category, you can be sure that it can reliably transmit data at a speed appropriate for this category. One of the principles laid down in SCS is a strict hierarchy of levels for constructing a cable system. Each level has its own specific functional purpose, physical topology and composition of components, strictly regulated by standards.

WORKPLACE SUBSYSTEM


The connection between the information outlet and the terminal equipment (computers, telephones, printers, etc.) is called the workstation subsystem. This includes connecting cords, adapters, as well as transmission devices that allow you to connect end devices to the network through an information outlet.

HORIZONTAL SUBSYSTEM


The horizontal subsystem covers the space from the Workplace Subsystem to the rooms with floor switching panels. It includes an information socket and components for connecting the socket to floor switch panels. The horizontal subsystem has a star topology, in which each information outlet is connected by its own cable to the floor switching equipment. When using a 4-pair copper cable in a horizontal path, it is required that all four pairs be connected to one data outlet. ISO 11801, CENELLEC EN50173, EN50174, TIA/EIA 568A & TSB67 standards establish that the maximum cable distance between switching centers and work areas should not exceed 90 m. An assessment of the maximum construction distances from the switching center shows that when they are located according to the technical specifications, the distance to the workers places do not exceed the norm. There is an extension of the Horizontal Subsystem definition known as zone architecture, or the "open office" concept. Zone architecture serves for a more flexible organization of horizontal cabling when frequent movements of the information outlet are required within one or more adjacent rooms. It involves dividing the horizontal wiring into two parts:
    A permanent connection from the patch panel to an intermediate point (zone block) that acts as a backbone. The permanent connection is rigidly fixed along the entire length and at the ends on the patch panel and zone block. Pluggable (flexible) connections from the zone unit to the information socket, which can be moved and reconnected when changing the location of the workplace.

VERTICAL SUBSYSTEM


The vertical subsystem is part of the SCS, which ensures the distribution of main cable lines throughout the building. It usually serves to connect horizontal subsystems to each other and to the equipment and administration subsystems. The vertical subsystem is built on multi-pair unshielded copper and optical cables. The vertical subsystem also includes related equipment used for cable distribution throughout the building.

EQUIPMENT SUBSYSTEM


The equipment subsystem consists of active network equipment and components that provide connection of this equipment to patch panels. The connecting components are connecting cords, connectors and elements for their fixation.

HIGHWAY BUILDING COMPLEX


The building complex backbone subsystem serves to connect communication equipment between the buildings of the complex. It includes the transmission media and associated equipment needed to enable communications between building communications equipment. These are external copper and optical cables, devices for protecting against electrical discharges and devices for connecting external and internal cables.

ADMINISTRATIVE SUBSYSTEM


The administrative subsystem consists of connecting wires and cords with the help of which physical connection subsystem lines connected to patch panels. Patch cords allow you to quickly and easily reconfigure the system without the use of special tools. ProfTelecom - What is SCS? Structured cabling systems (SCS) are the basis for creating information infrastructure.
Ensuring high throughput of the transmission path is the most important issue in the design and installation of technical security systems. It is especially relevant if it is necessary to solve the problem of video signal transmission, because video surveillance systems are highly informative systems, the volume of transmitted information and data in them is much higher than, for example, in a fire alarm system. Experts know: if the transmission path does not provide the necessary network bandwidth, all conversations about the nuances of the operation of high-quality video equipment can essentially turn into empty words.

Increasingly often faced with a similar problem, when installing complex security systems, customers turn not just to equipment suppliers, but to organizations that build structured cabling systems (SCS) for connecting video surveillance systems on their basis. There are many examples where companies that initially specialized in creating SCS successfully entered the market of technical security systems.

There is another good reason for these notes: not so long ago a new international standard for SCS was released. I consider it necessary to dwell in more detail on the issues of constructing structured cabling systems for security systems. Perhaps this will start a discussion of technical solutions proposed in this area.

SCS is a low-current telecommunications cable system that serves all engineering systems located in the building. The SCS must meet the following necessary requirements:
– have a standardized structure and topology;
– use only standardized components (cables, distribution devices, connectors, etc.)‏;
– provide standardized electromagnetic parameters (attenuation, bandwidth of transmitted frequencies, etc.) of communication lines organized with its help;
– managed (administered) using standardized methods.

A structured cabling system is a hierarchical cabling system of a building or group of buildings, divided into structural subsystems.

The structured cabling system consists of:
– a set of cables (copper and/or optical);
– patch panels;
– connecting cords;
– cable connectors;
– modular sockets;
– information outlets (IR)‏;
– auxiliary equipment.

All of the above elements are integrated into unified system and are operated according to certain rules.

All SCS must be built according to the same rules, have the same means of switching and connecting equipment, and provide previously known parameters of the data transmission medium. Recently, the concept of building a cable system has begun to take shape, i.e., a device made from a standardized range of components, built on a modular basis, with predetermined characteristics that ensure the functionality of the equipment connected to the SCS. Surprisingly, these ideas, long accepted and implemented, in particular, in mechanical engineering (a standard range of threaded connections, bearings, etc.), have only now begun to gain ground in the field of telecommunications.

Background
Early 50s last century - the date of birth of the first telephone networks. In the 80s The first cable solutions appeared: IBM connected its mainframes using a 93-ohm RG-62 coaxial cable in a star topology. The first cable solutions were presented by the largest manufacturers of computer and telephone equipment and were based on proprietary technologies. Many developments pursued exclusively private goals and objectives of a specific organization. The nascent local area network market suffered from a chronic lack of uniformity, which was inevitable as the industry's structure changed.

1987 - Committee TR41.8 (Electronics Industry Association) began developing a standard for indoor cabling.

1989 - the research organization Underwriters Laboratories, together with Anixter, developed a new classification of twisted pair cables.

1991 – publication of the ANSI/EIA/TIA-568 specification. The developers are the Electronic Industry Association (EIA) and the Telecommunications Industries Association (TIA).

In fairness, it must be admitted that for quite a long time even law-abiding Western companies ignored the recommendations of standards committees. This was partly the reason why the quality of services provided on the market has decreased.

Failure to comply with the requirements for installation and placement of SCS, its termination and testing was quite common. In this regard, the problem of improving the qualifications of industry employees has become acute. And the revision of the standards themselves soon became an urgent need. Serious institutions with an excellent reputation have appeared: TIA and CBM. These institutions worked actively to raise awareness of the prevailing standards and provide proper training to those who aspired to it.

1995 – two main regulatory and technical documents were adopted, describing SCS as a technical object. These are the American standard TIA/EIA-568-A and the international standard ISO/IEC 11801.

Despite the fact that both main documents describe the same technical object, they have quite serious conceptual differences, considering SCS from different positions, and largely complement each other. The second generation standard TIA-568-A (Commercial Building Telecommunications Cabling Standard) differed significantly from the previous document in that the use of coaxial cable was not recommended for the construction of newly created SCS and at the same time the use of single-mode fiber-optic cables in backbone subsystems was allowed.

In connection with the rapid development of information technology and the need to transmit increasingly large flows of information, the second edition of the ISO/IEC IS 11801:2002(E) standard was published in September 2002, in which new parameters were introduced and the values ​​of traditional parameters of components and paths based on twisted cables were clarified. pairs to ensure the transmission of information flows of Gigabit Ethernet network interfaces and similar ones in the horizontal subsystem.

From 2002 to the present, the development of information technology has not followed the path of a sharp increase in the volume of broadcast information flows, as predicted, but along the path of improving the manufacturability of the networks themselves. In this regard, in 2008 it was adopted new edition ISO/IEC IS 11801:2008(E) standard. This standard is a very voluminous and serious document that describes all the features of the construction and design of SCS.

Unfortunately, in Russia today there is no national SCS standard in the GOST R 34 “Information Technology” group of standards. Therefore, Russian designers, developers, suppliers, installers, and SCS owners are forced to base their work on international standards.

Components of SCS
If an SCS is designed and installed correctly, it can last 25 years or more and is thus a capital system. SCS is maintained in the same way as any capital system: regular inspections and checks, called testing and certification of the system for compliance with standards of a certain class. Preventative repairs of this system, routine maintenance, switching, etc. are possible. Only certified specialists have the right to build and provide guarantees for a structured cabling system.

To be able to classify and certify a structured cabling system, you need to know that the electromagnetic characteristics of SCS are defined by the ISO/IEC 11801:2008 (E) standard for certain configurations: channel and fixed line.

A fixed line (Permanent Link) is a passive section of the SCS between two directly connected points (interfaces) of connection to it, through which a signal can be transmitted. That is, a fixed line is a stationary cable and connectors at its ends (Fig. 1). The fixed line is designed to test the performance of a fixed cabling component.

The concept of Permanent Link was introduced in order to define a test configuration that most accurately characterizes the parameters of the permanent part of the cable system. The Permanent Link configuration requires that the contributions of the patch cables used to access the line under test be excluded from the measurement results. Therefore, the limit test values ​​for Permanent Link differ from those for Link by an amount attributable to the tester's connecting cables according to an a priori estimate. The total length of the Permanent Link line can be up to 90 m.

A landline line does not include the cords used to connect the sending and receiving devices, nor does it include any patch cords.

Channel is a passive path capable of transmitting a signal from end to end, connecting any two active blocks electronic equipment, for example, a workstation and a LAN switch (Fig. 2).

Channel, according to the ISO/IEC 11801:2008(E) standard, is the path for interaction between active network equipment. The concept was introduced in 1999. The channel includes a fixed SCS line and various cords used for connection. Channel as a measurement object - this model was introduced to achieve a better approximation of the final configuration of the user system.

The standard describes two fundamentally different measurement objects: a fixed line (Permanent Link) and a channel (Channel). The document provides the corresponding ones for both objects. If there are special requirements, at the stage of acceptance testing, a selective or complete check of the parameters of the channel or fixed line can be performed.

It is convenient to work with the channel model during the current operation of the SCS when troubleshooting.

Performance limits for balanced cables are strictly defined by the components on which the channel is built (ISO/IEC 11801:2008(E)). For maximum values, this is 90 m of single-core copper cable, 10 m of various cords and 4 joints (1 joint is a plug and socket connected together). For class F, the current version of the standard allows only 2 joints.

As you know, active switches, video recorders and other similar equipment impose different bandwidth requirements on information transmission channels. Therefore, electrical channels and lines are divided into six classes: A, B, C, D, E, F. Channels and lines of these classes provide guaranteed support for the corresponding classes and all lower classes. The components from which a structured cabling system is created (cables, connectors, plugs, sockets) are also classified in the ISO/IEC 11801:2008(E) standard according to the bandwidth of transmitted frequencies; different requirements are also imposed on the quality of installation.

Application classes
Class A: lines specified up to 100 kHz for voice and low-speed data transmission - video transmission.
Class B: lines specified up to 1 MHz for medium-speed data transmission - transmission speed 1 Mbit/s.
Class C: lines specified up to 16 MHz for high-speed data transmission - transmission speed 10 Mbit/s.
Class D: lines specified up to 100 MHz for ultra-high-speed data transmission – transmission speed 100 Mbit/s – 1 GBit/s.
Class E: lines specified up to 250 MHz for ultra-high-speed data transfer at speeds up to 1 GB/s.
Class F: lines specified up to 600 MHz for ultra-high-speed data transfer at speeds of 1 Gb/s - 10 Gb/s.

That is, if we choose high-quality video surveillance cameras that generate high-resolution frames, which means large volumes, high-quality video recorders or switches that broadcast the resulting image in live video mode to the network, which will also take up a considerable amount of traffic, and we organize the broadcast via a cable system , obviously of a lower class or incorrectly designed, then the image quality will be irretrievably lost, and the live video mode will not be achieved either. Consequently, the investment made in equipment will not justify itself.

In addition to the frequency range, the ISO/IEC:2008(E) standard sets clear requirements for the parameters of channels and fixed lines, both based on twisted pairs and fiber-optic cables. For systems based on twisted pairs, channels of classes D, E, F must have a characteristic impedance of 100 Ohms; for classes A, B, C, a value of 100 Ohms is preferred, but a value of 150 Ohms is also acceptable. Also stratified are parameters such as return loss, input loss, structural return loss, near-end security (NEXT), total near-end coupling attenuation (PSNEXT), far-end coupling attenuation (FEXT) and its total value (PSFEXT), near-end attenuation-to-coupling ratio (ACR), total near-end coupling loss normalized (PSARC), input loss normalized far-end coupling loss (ELFEXT), total input loss normalized far-end coupling attenuation input (PSELFEXT), signal delay (PD) and delay skew (DS).

The use of cable structure parameters is inevitable during the installation of a video surveillance system. The installer needs to calculate the location of the power supply and camera. According to the international standard ISO/IEC11801, a twisted pair cable of category 5 (class D) 100 MHz with a data transfer rate of 1 Gb/s has a resistance of no more than 20 ohms per 100 m (actually about 2 ohms per 100 m). Over 300 m of twisted pair, the voltage drops no more than 6 V. Therefore, the power source can be connected at a distance of about 300 m from the camera. For more accurate calculations, it is necessary to test the structured cabling system.

It is advisable to say a few words about SCS based on fiber-optic cables. The main standardized parameters of fiber optic lines are numerical aperture (NA), attenuation (A), and broadband coefficient (K).

In lines using optical cable for high-speed and ultra-high-speed data transmission, bandwidth is not considered as a limiter. The numeric value specified in the class name determines the minimum channel length in meters at which a channel of this class is guaranteed to support the corresponding application if the channel is created in accordance with the requirements of the standard:
Class OF-300: from 300 m.
Class OF-500: from 500 m.
Class OF-2000: from 2 km.

The top-of-the-range OF-2000 enables applications including Gigabit Ethernet 1000Base-LX over single-mode OS1 fiber up to 2000 m with an IL of 4.56 dB in a 1310 nm window.

The OF-500 class enables Gigabit Ethernet 1000Base-LX applications over OM1, OM2 and OM3 multimode fiber up to 500 m with an IL of 2.35 dB in a 1300 nm window.

The increase in channel length from 550 to 2000 m in the 1300 nm window is achieved by improving the refractive profile.

The standard specifies a bandwidth (broadband coefficient) for laser input of at least 2000 MHz x km in the 850 nm window for OM3 fibers.

Consequently, the choice of transmitting equipment, for example active switches, for transmitting a video signal must be made either taking into account the existing SCS at the facility, or taking into account the territorial extent of the facility and the rules for designing a structured cable system on fiber-optic lines.

In conclusion, it is necessary to pay attention to the following fact.

The only company that conducts SCS market research in all countries of the world is the independent consulting company BSRIA - Building Servies Research & Information Association, located in the UK.

According to the official BSRIA report on the copper SCS market for 2007 in Russia, Eurolan SCS ranks 3rd with a market share of 8.7%, second only to Typo Electronics (10.8%) and Systimax Solution (16.9%) .

LITERATURE:
Networks and communication systems, No. 6, May 5, 2008, p. 11. Samarsky P. A. Fundamentals of structured cable systems. M.: 2005.

*Price per one SCS line.

SCS is the basis of a computer local network (LAN)

For the organization to operate, a local network is required that connects computers, telephones, and peripheral equipment. You can do without a computer network. It’s just inconvenient to exchange files using floppy disks, line up near the printer, and implement Internet access through one computer. The solution is a technology abbreviated as SCS.

A structured cabling system is a universal telecommunications infrastructure of a building or complex of buildings, providing transmission of signals of all types, including voice, information, and video. SCS can be installed before user requirements, data transfer rates, and the type of network protocols are known.

SCS creates the basis of a computer network integrated with the telephone network. The collection of telecommunications equipment of a building/building complex, connected through a structured cabling system, is called a local area network.

SCS or computer plus telephone network

Structured cabling systems provide long service life, combining ease of use, quality of data transmission, and reliability. The implementation of SCS creates the basis for increasing the efficiency of the organization, reducing operating costs, improving interaction within the company, and ensuring the quality of customer service.

A structured cabling system is built in such a way that each interface (connection point) provides access to all network resources. In this case, two lines are enough at the workplace. One line is computer, the second is telephone. The lines are interchangeable. Cables connect telecommunications connectors of workplaces with ports of distribution points. Distribution points are connected by trunk lines according to the “hierarchical star” topology.

SKS is an integrated system. Let's compare SCS with the outdated "computer plus telephone network" model. A number of advantages are obvious.

  • an integrated local network allows you to transmit different types of signals;
  • SCS ensures the operation of several generations of computer networks;
  • SCS interfaces allow you to connect any equipment of local networks and voice applications;
  • SCS implements a wide range of data transfer rates from 100 Kbit/s for voice applications to 10 Gbit/s for information applications;
  • administration of SCS reduces labor costs for maintaining the local network due to ease of operation;
  • a computer network allows the simultaneous use of different types of network protocols;
  • standardization plus competition in the SCS market ensures lower prices for components;
  • the local network allows for the freedom of movement of users without changing personal data (addresses, telephone numbers, passwords, access rights, service classes);
  • SCS administration ensures transparency of the computer and telephone network - all SCS interfaces are marked and documented. The work of the organization does not depend on the employee monopolist of telephone network connections.

A reliable and durable structured cabling system is the foundation of a local network. However, every dignity has reverse side. SCS standards recommend redundancy of quantitative system parameters, which entails significant one-time costs. But you can forget about the nightmare of permanent renovation of an existing office to expand a computer network to meet current needs.

SCS standards

SCS subsystems

The ISO/IEC 11801 standard divides structured cabling into three subsystems:

  • main subsystem of the building complex;
  • main building subsystem;
  • horizontal subsystem.

SCS backbone subsystem and telephone network

The backbone subsystem of the building complex connects the cable systems of the buildings. The backbone subsystem of the building connects the distribution points of the floors.

The trunk subsystem includes information and speech subsystems of the SCS. The main transmission medium of the information subsystem is optical fiber (single-mode or multimode), supplemented by symmetrical four-pair cables. If the length of the main line does not exceed 90 meters, symmetrical cables of category 5 and higher are used. For longer lengths, information applications, i.e. computer networks, require fiber optic cables.

Building backbone speech applications operate over multi-pair cables. Speech applications that create a telephone network belong to the lower classes of SCS. This allows you to increase the length of the backbone subsystem lines created by multi-pair cables to two to three kilometers.

Horizontal subsystem of SCS and computer network

The horizontal subsystem of the SCS includes distribution panels, patch cables of floor distribution points, horizontal cables, consolidation points, and telecommunication connectors. The horizontal subsystem provides a local network for subscribers and provides access to backbone resources. The transmission medium of the horizontal subsystem is symmetrical cables of at least category 5. The SCS standards of 2007 provide for data processing centers the choice of SCS not lower than category 6. For information technologies (computer plus telephone network) of private homes, the new standards recommend the use of category 6 / 7. Transmission medium broadcast communication technologies (abbreviated VKT: television, radio) of private houses / apartments - symmetrical protected cables with a frequency band of 1 GHz, plus coaxial cables up to 3 GHz. The use of optical fiber is also allowed.

The horizontal subsystem of SCS is dominated by a computer network. This results in a limitation on the maximum length of the channel - 100 meters, regardless of the type of medium. To extend the service life without modifications, the horizontal subsystem of the SCS must provide redundancy and reserve parameters.

Work area in the structure of the horizontal subsystem of SCS

The SCS work area is the premises (part of the premises) where users work with terminal (telecommunications, information, speech) equipment.

Telecommunication grounding buses (TGB) are installed in each distribution point near cabinets/racks. The distribution point buses are connected by grounding lines to the main telecommunications grounding bus (GTSGB), installed next to the electrical grounding terminal. Modern standards recommend increasing the cross-sectional area of ​​the grounding line conductor as the length of the line increases. The maximum recommended gauge may be 3/0 AWG or 90 sq. mm. The branches of the main line are made by isothermal welding or permanent connection.

We often have to deal with the absence or improper implementation of grounding systems in old buildings. Designing a telecommunications grounding system does not require eliminating electrical grounding deficiencies. When ground equipotentiality is not ensured, the principle of “effective shielding” is implemented.

Power supply system

In most cases, for a computer network to operate, it is necessary to provide power to devices connected to telecommunications connectors. Power sockets are installed at each workplace. Some sockets are used to connect computers and office equipment, others – household electrical appliances. This separation of systems makes it possible to organize a centralized guaranteed power supply.

It is known that laying power cables parallel to information cables degrades the quality of data transmission over low-current lines, which can cause failures of local networks. To reduce this influence, it is necessary to maintain the minimum permissible parallel laying distances, which depend on voltage and load power. Installation of power and low-current networks by one contractor allows you to solve the problem of electromagnetic compatibility and reduce investment costs.

Socket installation options

Power and telecommunication sockets can be installed in boxes, overhead sockets, walls, telecommunication columns, floor hatches.

The photographs show options for placing telecommunication connectors (TP) with power socket blocks. The most common option for creating cable channels is plastic boxes. Walls, office furniture, even ceilings are used to fix boxes. Boxes with a height of more than 80 mm are convenient for placing sockets. Narrow boxes are complemented by wall socket boxes.

Groups of sockets can be marked with markings or the color of the inserts. For example, red inserts are for powering a computer network, white ones are for connecting household electrical appliances.

Telecommunication columns, floor racks, floor hatches are used less frequently. The reason is the higher cost of such solutions.

The cheapest option is built-in sockets. It is also the most aesthetically pleasing. The implementation of this method of installing sockets is optimal when building or renovating an office. An alternative inexpensive option is to install wall socket boxes and lay mini-boxes.

Testing and Warranties

The opinion that SCS testing is a formal procedure is very common. Many customers believe that measuring line parameters is a warranty procedure. This is true, but only half. First, testing reveals hidden defects that may go undetected. Secondly, this is the only way to avoid problems with computer network applications.

Contrary to popular belief that SCS standards fully comply with the requirements of network protocols, this is a misconception. Transmission media parameters are lower than application requirements. SCS standards of classes D (100 MHz), E (250 MHz) and F (600 MHz) provide for a zero - negative attenuation / total interference ratio at the upper limit of the frequency range. For working pairs of class D applications implemented in computer networks, the signal-to-noise ratio over the entire frequency range must be at least 10-19 dB, that is, one to two orders of magnitude better than what the SCS standards provide. Moreover, some Class D applications operate in frequencies greater than 100 MHz, defined by Category 5e. The frequency range of 1000BASE-T Gigabit Ethernet is 125 MHz, ATM 155 – 155 MHz.

Thus, an SCS may comply with the standards, but not ensure the operation of a number of local network applications in terms of the bit error rate (BER) parameter. At the same time, the data transfer speed decreases until the computer network freezes.

The quality of signal transmission over SCS channels is ensured thanks to a reserve of parameters. Compliance testing with network protocols is performed to verify that the reserve is sufficient. For example, when using a Fluke cable analyzer (sample report), baseline/channel compliance with eleven network protocols is confirmed. This means that any lower class applications can also be used.

Line testing

Warranty certificate SCS ITT NS&S (UK)

Warranty certificate SKS Panduit / Belden (USA)


After installation is completed, all SCS lines are subject to testing. Project documentation with the test results is provided to the SCS manufacturer. After verification, a warranty certificate is issued. The warranty period for SCS is 10 – 25 years. In particular, for ITT NS&S and Panduit - 25 years. Warranties for the power supply system from one to three years are provided by the installation companies.

The problem of choice

A tender is held to select a contractor. The customer determines the category of SCS, the type of shielding, the availability of guarantees, leaving all other issues at the discretion of the tender participants. Bidders must convince the customer of the best quality/price ratio of the proposed solution. The choice of SCS contractors often determines the choice of the manufacturer of the system itself. Companies offering different systems offer prices for several SCS options from different manufacturers.

The quality of the SCS consists of the reserve of parameters provided by the manufacturer, as well as the qualifications of the performers performing the installation.

The reliability and performance of the cable system largely depends on the implemented design solutions. For example, the cable length will be minimal, which directly affects the operation of the local network. The shorter the channel length, the less signal attenuation, the better the signal to noise ratio. It is advisable to shield lines of maximum length. Design is based on a large body of rapidly evolving standards. Therefore, the choice of system, cable category, type of connectors, the presence of shielding, and reasonable redundancy of SCS parameters are important. This reflects the prospects for growth in network needs and the load on the Customer’s local network.

To install SCS, you need to prepare cable channels, carefully lay the cables, and connect them to the connectors. Connection requires untwisting of pairs, that is, imbalance, or, in other words, a decrease in the quality characteristics of the system. Most often, negative test results are caused by the installation of connectors. Good qualifications of installers, verified by testing results, solve the problem. There are other possibilities. Modular connectors from a number of manufacturers reduce the risk of imbalance to a minimum thanks to special installation technology.

High-quality SCS and a reserve of functional parameters ensure long-term trouble-free operation of the local network, which guarantees a quick return on investment and increased efficiency of the organization.

Structured cabling system (SCS) is physical basis building infrastructure, which combines various network information services into a single complex.

Such services are:

Figure 1 - Structured building cabling system

Principles of construction of SCS

A structured cabling system ensures the transmission of signals of all types and is the basis of a local area network (LAN). A LAN connects phones, computers and other equipment. Each connection point provides access to all network resources. Therefore, at each workplace there are enough two lines - a computer and a telephone. These lines can be interchanged.

Below are the basic principles for constructing SCS.

Structuring

Cable wiring and its components are divided into separate subsystems. Each subsystem performs specific functions and communicates with other subsystems and network equipment. Each subsystem has switching capabilities that allow you to easily change the system configuration. When building a system can be used various types cable and switching equipment, depending on the conditions of a specific project.

Versatility

The cable system is built according to the principles of open architecture with technical characteristics, defined in the standards. The parameters of electrical and optical cable routes of subsystems and their interfaces are specified in the regulatory documentation. Thus, the cabling system can be used to transmit signals for various applications using only two types of cables - twisted pair and optical fiber.

Switching of SCS subsystems with each other and with active network equipment is carried out by a certain set of cords with universal connectors, which facilitates the administration of the cable system and its adaptation to various applications.

Redundancy

SCS provides for the possibility of expansion - its topology and equipment provide the opportunity to increase the number of connected equipment and the volume of traffic. All SCS equipment is selected with reserves for performance, the possibility of installing additional modules and expanding functionality.

Reliability

Manufacturers of SCS guarantee the functionality and compliance of the cable system with standards throughout its entire service life. In the event of an accident in the SCS, the faulty section is quickly localized, a transition to the backup line is carried out, and renovation work. Restoration of the SCS operation is carried out without stopping the network operation by the SCS administrator, without the involvement of third-party specialists.

Flexibility

A functioning SCS provides the following capabilities without changing the cable system and without any additional costs:

  • modification of the software and hardware complex;
  • control the movement of users in the building;
  • change in the number of users;
  • dividing users into groups according to various characteristics.

Economical

Large initial investments in SCS quickly pay off due to lower costs for modification and support of telecommunications infrastructure. The service life of SCS is significantly longer than the life of other components of the information system (active network equipment, servers and personal computers, software, telephone exchanges and communication equipment, etc.).

Durability

SCS will ensure a gradual transition to high-speed protocols that will work for the future by simply replacing active equipment, without requiring reconstruction of the cable system. The technological stock of characteristics and SCS standards guarantee that obsolescence of cable wiring will not occur ahead of schedule when its system warranty ends (for most manufacturers it is 20 years).

SCS subsystems

SCS is a cable system of a building (group of buildings) of a hierarchical type, which consists of structural subsystems. Each subsystem performs its own functions and has a specific topology and composition of components. For each type of subsystem, the standards define requirements, restrictions and rules.

SCS cable subsystems:


Figure 2 - SCS subsystems

EDP ​​- floor distribution point;

GRP - main distribution point;

PRP - intermediate distribution point.

Trunk subsystem of the first level

The trunk subsystem of the first level is located between the main distribution point and the intermediate distribution point, as well as between the main distribution point and the floor distribution point.

This subsystem includes:

  • Level I trunk cables;
  • distribution devices used for the I-level trunk cable;
  • patch jumpers and cords that are used for switching at the main distribution point.

Trunk subsystem of the second level

The intermediate distribution point divides the main SCS system into a main level I subsystem and a main level II subsystem.

This subsystem includes:

  • Level II trunk cables;
  • distribution devices used for the Level II backbone cable;
  • patch jumpers and cords that are used for switching at an intermediate distribution point.

Horizontal subsystem

The horizontal subsystem is located from the distribution devices of the floor distribution point to the telecommunication sockets.

This subsystem includes:

  • horizontal cables;
  • distribution devices used for horizontal cables;
  • switching jumpers and cords that are used for switching with the floor distribution point;
  • telecommunications outlets;
  • consolidation points.

SCS components

A structured cabling system is created during the construction of a building or refurbishment of premises and has a guaranteed service life of at least 10 years.

SCS includes the following equipment:

  • telecommunication cabinets;
  • server cabinets;
  • cables;
  • wire trays;
  • Column;
  • patch panels;
  • electric brushes;
  • connectors;
  • sockets (computer, telephone);
  • telephone plinths;
  • cross panels.

SCS architecture

There are two types of SCS architecture:

  • distributed;
  • centralized.

Distributed SCS

Distributed architecture is most often used for SCS of multi-storey buildings and building complexes. A distributed architecture can have one or two levels of hierarchy. In the first case, the main distribution point is connected to the floor distribution point using a cross. In the second case, the SCS consists of three subsystems: the main level I, the main level II and horizontal subsystems.

Figure 3 - Distributed SCS

Advantages of distributed architecture:

  • greater flexibility of SCS;
  • ease of expansion of the cable system;
  • ease of installation of the cable system.

Disadvantages of distributed architecture:

  • cumbersome cable system (large number of components);
  • large area of ​​telecommunications premises;
  • complexity of control and security.

Centralized SCS

A centralized architecture may have one hierarchy level with no horizontal or backbone subsystem cross-connection, or no hierarchy levels at all and consist only of a horizontal subsystem.

Figure 4 - Centralized SCS

Advantages of centralized SCS architecture:

  • a small number of cable system components;
  • small area of ​​telecommunications premises;
  • a small amount of active equipment;
  • lack of active and passive equipment for organizing the highway;
  • simplicity of organizing a redundancy system for active equipment.

Disadvantages of centralized SCS architecture:

  • a large amount of cable;
  • low flexibility of the cable system;
  • difficulty in expanding SCS;
  • complexity of installation;
  • the difficulty of delimiting the area of ​​responsibility in a telecommunications premises when renting a building to different organizations.
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