So you want to install network cables but don't know where to start.

You could enroll for some formal training, there are a few recognised courses on structured cabling systems which offer some hands-on experience, or you could take one of the many courses offered by the manufacturers of cabling components. Obviously the manufacturers try to sell their own products, but their courses are usually cheaper and they can still provide some of the basic cabling skills. |

There are also lots of books on the subject of cabling and a selection of these can be found in the Network Cabling Help shop, my personal favourite is The Cabling Handbook 2nd Edition by John Vacca. It has over 1300 pages covering all aspects of network cabling and includes chapters on The Standards, Network Design, Wireless Communications, Fibre and Home Wiring.
If you don't want to invest any money on training until you are seeing some financial results, then you can gain valuable experience by actually doing some work for an existing cabling company.
Here are some basic questions you may be asking yourself if you have never installed a structured cabling system before.
What are 'The standards' ?
There are three main cabling standards: * EIA/TIA 568A - This is the American standard and was the first to be published (1991). * ISO/IEC 11801 - The International standard for structured cabling systems. * CENELEC EN 50173 - The European cabling standard.
The reason for having a 'Standard' is to define a method of connecting all types of vendors voice and data equipment, over a cabling system that uses a common media, common connectors and a common topology. This means that a building can be cabled for all its communications needs without the planner or architect ever having to know what type of equipment will be used.
It is advisable to get a copy of one of the cabling standards documents, although once you have read through it once and understood some of what it describes, it will probably be filed away and never opened again. If you have ever tried to read a standards document you will know that it is hard work. Trying to separate the useful information from all the technical jargon can be very time consuming and even then you may not find the answer to your question. The bad news is, the Cabling Standards are no different, they are full of cross references, formulas and tables all of which can be a very daunting prospect and can make the installation engineer think twice about installing the stuff.
Now for the good news, the standards are mostly concerned with the performance criteria of the components of a cabling system, and, as that is guaranteed by the manufacturers of the different cabling components, you don't have to worry about it. Great eh!

What type of cable do I install?
Please go to the Questions and Opinions page for my personal views on the subject.

What materials do I need?
Lets work on a hypothetical installation. It is for 30 double outlets, in one building, with an average run of about 30m. Each double outlet will be used for one PC and one telephone. A detailed breakdown of this list giving reasons for sizes and quantities is Here

* 1 x 27U, 600 x 600 cabinet. * 3 x 32 way RJ45 patch panels. * 6 x boxes of Cat 5e cable. * 30 x double Cat 5e outlets and backboxes * 30 x PBX master telephone adapters * 30 x 1.5m patch leads * 30 x 2m patch leads * 30 x 3m fly leads. * Trunking, cable ties and a method of labelling the system.

How do I install it?
Here are the basic do's and don'ts.
Although the maximum cable length for a Cat 5e/6/7 system is often reported to be 100m, this length is inclusive of patch and drop leads. Cable testers however, when set to perform a 'Basic Link' test, take this into account and you will find that the maximum length is set to either 90m or 94m depending on the standard you are testing to. Also, because the length is measured with a Cable Analyser it is not the physical length of the run but the copper length that is measured. The copper length is longer due to the twists in the cable pairs, so if a run looks like it might be over 85m it would be wise to check it before it is tied up and terminated.
Each outlet cable should be run directly back to the patch cabinet, that is one cable per outlet. A transition point or connection box is allowed if necessary, but in practice this can be more trouble than its worth.
Care should be taken when pulling cables in to ensure that they are not kinked or nicked.
Cable routes should be planned to avoid fluorescent light fittings and power cables (exceptions can be made in the case of optical fibre). They should not be run in the same conduit as power, or the same channel of a trunking system, and where they are run parallel to power they must be at least 60mm apart (BS7671-92) . Crossing power cables is allowed but it must be at right angles, and some form of bridge should be used.
A means of supporting the cables should be installed such as cable tray, catenary wire or cable tie fixings, tying cables to ceiling hangers is not permitted. Cables should be tied at a minimum of 500mm intervals on horizontal runs and more frequently on vertical runs, with no more than 48 cables in a loom. Cable ties should only be finger tight to avoid crushing the cables as this could affect the cables performance characteristics. Do not use cable tie guns or staple guns.
Cable trays should be used under false floors, if not, a suitable method of keeping the cable off the floor slab should be employed. This is because the lime in the concrete apparently reacts with the cables sheathing, and over time could damage the cable. I personally think the cable will have outlived its usefulness long before this could have any affect on the cables performance.

Care should be taken when pulling cables into trunking to avoid damage due to snagging. Trunking partitions should be used to separate the data cables from power, and bridges should be used where data cables have to cross the mains.

When terminating patch panels, cable looms should not exceed 48 cables. Each cable loom should then be tied in a tidy manner to a cable tray fitted the full length of the cabinet.
All terminating should be carried out according to the manufacturers instructions and guidelines, and the standards for generic cabling systems. The cable sheath should be stripped back no more than 13mm from the point of termination and the twist rates should be maintained.
Cable ties MUST be fitted to the individual RJ45 modules in the patch panels and outlets to support each cable.
When terminating outlets, care must be taken to avoid damaging the copper cores when stripping back the outer sheathing.
Excessive amounts of cable should not be left in the outlet backbox. Care should be taken when attaching the outlet faceplate not to kink, trap or strain the cable.
Cable tray should be fitted in cabinets housing structured cabling to keep cable looms secure and tidy, and to provide room for any additional cabling.
All cabinets must be earthed to the 16th edition IEEE wiring regulations (British regulations). Where shielded cable is used the earth should be clean and where two cabinets are linked with a copper backbone (shielded or unshielded) a minimum of 10mm² earth wire should also be installed to cross bond the cabinets. Testing and documentation
All testing whether copper or fibre should begin with calibration of test equipment, and batteries should be fully charged before testing begins. Descriptions of the various test parameters can be found on the Cable Testing page.
On all installations, and particularly on large jobs, two way radios, mobile phones or internal telephone lines should be used to ensure correct numbering of outlets and patch panels during testing. What do they mean by Balanced line? How does it work?
Balanced line operation is a transmission method which helps to eliminate the effects of noise on the cable. In the first diagram a coaxial cable is transmitting a 4V signal, this is unbalanced as all of the 4V signal is carried by the centre core of the coax with respect to the grounded screen. If 1V of noise is introduced, it adds to the signal being transmitted making 5V, this could interfere with our data.

With a balanced line transmission our 4V signal is split into +2V and -2V on one twisted pair, so we still have 4V between the two. Now when we introduce the 1V of noise, the +2V becomes +3V, and the -2V becomes -1V, but the potential difference between the two is still 4V. The devices we put on the ends of the cable to make the line balanced are called baluns, this name is derived from the function of the devices of converting between balanced and unbalanced transmission modes.

These days, more and more equipment is being designed to operate on balanced lines without the need for baluns, but there are still a lot of older systems out there that still use these converters.
MHz? Mbps? Baud?
If you are confused about the different terms used in data communications this article written by Mark Barratt should help to clear things up.
Bandwidth is the difference between the highest and lowest frequencies which will propagate through an equipment or system. In many cases, the lower limit is DC, zero hertz, and so the bandwidth is the same as the upper frequency limit. The public telephone system constrains all signals to the range 300 Hz - 3 kHz. Its bandwidth is therefore 2.7kHz.
In the most obvious method of modulation (representing data electrically), two different voltages are used to represent a '1' and a '0'. The receiver expects a data bit at a certain time, and samples the input voltage to determine the value of the bit. This is called "amplitude shift keying" (ASK). The maximum frequency of the signal will depend upon the slew rate (the time taken to change from 0 to 1, or vice versa). The maximum slew rate is the upper frequency limit, and the slew rate, in turn, limits the maximum data rate.
Plainly, the bandwidth of such a system directly limits the data rate, but in theory it need not. Consider a protocol which uses "frequency shift keying" instead. Here, two different frequencies (both of them within the legal bandwidth) are used to represent 1 and 0. The maximum data rate is now the maximum speed at which you can shift between the two frequencies. This is still limited by the bandwidth, but not so directly - the resulting maximum data rate is higher. And what happens if you use more than two frequencies? You can then transmit more than one bit of information per signal transition, upping the data rate again without increasing the maximum frequency of the signal.
It is techniques such as these which have allowed the development of 56k modems. Using a combination of multiple-level amplitude, frequency and phase modulation, they manage to extract up to 56,000 bits per second of performance from the aforementioned 2.7 kHz bandwidth. To achieve this using plain 2-level ASK would require a bandwidth of hundreds of kilohertz. "Baud rate", strictly, is a measure of "signal elements" per second, and is not a useful measure where the above signalling techniques are being used. Such systems are generally rated in "bits per second" bps. It is worth noting that manufacturers will claim the highest figure they can for this parameter, so that the figure will include bits which are part of the signalling protocol rather than the user's data, and may even incorporate an assumption about the compressibility of the data. It is rarely (if ever) valid to divide bps by 8 to arrive at bytes of data transmitted/expected per second. Written by
Mark BarrattAll EditorsDesign Structured Cabling Systems and IT Network Infrastructuresupdated Dec 29, 2008 6:51 pm | 106,381 views Contents [Hide TOC] * 1 Introduction * 2 Steps * 2.1 Step 1: Which group of standards will you conform to? * 2.2 Step 2: Horizontal cabling - Basic rules * 2.3 Step 3: Backbone Cabling * 2.4 Step 4: Campus Cabling * 2.5 Step 5: Positioning and design of Telecommunications Closets to link horizontal and backbone cabling. * 2.6 Step 6: Cable containment system * 2.7 Step 7: Cable Administration system * 2.8 Step 8: Earthing Scheme * 2.9 Step 9: Testing regime * 2.10 Step 10: Final thoughts * 3 Examples * 3.1 Links[edit]IntroductionDesigning a Structured Cabling System - a ten step HOWTO guide [edit]StepsBelow we have provided a ten step introductory guide for the Design of Structured Cabling Systems and IT Network Infrastructures. (see structured cabling schematic) [edit]Step 1: Which group of standards will you conform to?European Union CENELEC EN standards America ANSI/TIA/EIA standards Canada CSA standards Australia/New Zealand AS/NZ standards Rest of the World ISO/IEC standards The three principle design standards give the details of how to design and specify a structured cabling standard, they are; * ISO 11801 * EN 50173 * TIA/EIA 568-A or 568-B BICSI
These standards in turn however refer to hundreds of other standards relating to component specifications, fire performance, testing methods, containment systems etc. [edit]Step 2: Horizontal cabling - Basic rulesFour-pair cables are run from user positions to a patch panel. At the patch panel, patchcords link into the active LAN equipment or into backbone cabling. The user position has a wall outlet or floor outlet, and this links into the PC on your desk via another patchcord. The outlet is a called a TO (Telecommunications Outlet) and contains an eight way plug meeting IEC 60603-7, more commonly referred to as an RJ-45. * Two outlets per work area * Two outlets per 10 square metres of useable floor space * Outlets to be within 3 metres of the user station * Both outlets to be RJ 45 * Max cable run to be 90 m * Max total length of patchcords at both ends of the link to be 10 m * Cable and RJ45 to be Cat5e grade Options Cat 3 or optical fibre can be used If optical fibre, select 50/125 or 62.5/125 multimode If using fibre select SC or ST connectors Cat 6/Class E can be specified Cat 5e Cable can be unscreened, UTP, Foil screened, FTP, or Foil and Braid screened S-FTP. Cable fire performance can be: 1. IEC 332-1 2. IEC 332-1, IEC 754, IEC 1034 3. IEC 332-3-c. IEC 754, IEC 1034 4. UL 910 plenum Each grade, in ascending order, has a better performance in fire situations but at a correspondingly higher price. The exact density of cables, number of outlets and their position is up to the end user, or else at the proposal of the installer/designer [edit]Step 3: Backbone CablingAll of the horizontal cables are star-wired back to Telecommunications Closets or Floor Distributors where they are terminated in patch panels. These patch panels are connected together via the building backbone cabling which can be up to 500 metres long. It can be copper cable but is more likely to be optical fibre, either multimode or singlemode. The kind of cables and the number of cores needs to be decided.If fibre is chosen, a loss budget should help you make your decision [edit]Step 4: Campus CablingThe campus cabling links different buildings together. It can be up to 1500 m long. It can be copper cable but is more likely to be optical fibre, either multimode or singlemode. The kind of cables and the number of cores needs to be decided. [edit]Step 5: Positioning and design of Telecommunications Closets to link horizontal and backbone cabling.Positioning and design of the equipment room as a central focus for the main computing, LAN and PABX equipment. Positioning and design of the Service Entrance facility whereby outdoor cables are terminated and the point of demarcation between customer owned equipment and the PTT cables is defined. [edit]Step 6: Cable containment systemHow will the cables be protected? Within buildings the choices are: * Cable trays * wire basket/raceway * cable ladders * J hooks * conduit * dado rails * PVC trunking * built-in underfloor duct * raised floors * suspended ceilings The following must be taken into account: * the density and volume of cables to be organised * the aesthetic appearance of the cabling within offices and other visible areas * economics of different schemes * proximity to power cables and other potential sources of interference * firestopping Useful standards are: * TIA/EIA 569 Commercial building standard for telecommunications pathways and spaces * EN 50174 Information technology – cabling installation For external applications the choices are: * underground cable ducts * direct buried cable trench * concrete cable trough * self supporting aerial cable * supported aerial cable, i.e. catenary or messenger wire * fixed to building exteriors In all cases the designer must ensure that all civils work has been carried out, rights of way established and availability of cable ducts and manholes established. Aerial cable routes must keep a minimum distance away from power cables and all external cables must be selected for the environment and temperature ranges in which they are expected to survive. External copper cables usually need to be protected by overvoltage and fault current devices where they enter a building. [edit]Step 7: Cable Administration systemThe cabling and its containment system need to be clearly identified and their locations, routes and capabilities recorded in a cable administration system. This usually involves a logical numbering scheme that can be applied to all cables, outlets, patch panels and even containment systems. Various colour schemes are also available. These schemes can be paper based but for the larger installations then a computer based system is advisable. There are several proprietary solutions on the market which offer various database and graphical methods for keeping track of cabling assets. Some systems are also active in that they can detect moves and changes and automatically update the database. Useful standards are: * TIA/EIA-606 Administration standard for the telecommunications infrastructure of commercial buildings * EN 50174 Information technology – cabling installation [edit]Step 8: Earthing SchemeAll exposed metallic elements of the cable system and cable containment system need to be earthed (grounded) for safety and also electromagnetic compatibility requirements. If screened cables are used then special attention must be given to effective bonding of the screening elements. Poorly earthed screened cabling may behave worse than unscreened cabling. An electrically ‘clean’ earth must be available at all points where the cabling is terminated, but especially within telecommunication closets, equipment rooms and service entrances. A clean earth is usually defined as a conductive element with not more than 1 volt rms potential difference between it and the real earth down below. Copper cabling linking two different buildings can suffer from earth loops if the ground potential is different. Non-metallic optical cabling is usually picked for problem areas such as these. Some useful standards are: * PrEN50303 Application of equipotential bonding and earthing at premises with information technology equipment * PrEN50174-2 Information Technology, Cabling installation, part 2, Installation, planning and practices inside buildings * TIA/EIA-607 Commercial Building Grounding and Bonding Requirements for Telecommunications [edit]Step 9: Testing regimeAll cables must be tested to demonstrate compliance with the standards and specification to which they were bought. Testing can be split into copper cable testing and optical fibre testing. Ideally all cables should be 100% tested. Copper cables. There are five manufacturers of hand held copper cable testers that will automatically test the installed cable plant for all the expected parameters. By the use of a remote injector, the cabling is tested from both ends, which is a condition of the standards. The cabling has to pass all of the suite of tests to be awarded and overall pass. Points to remember are; What is being tested? the channel (i.e. end-to-end including all the patchcords) or the basic link (i.e. the permanently installed cable from outlet to patchpanel). The test figures are different for each setting. It is usually more practical to test the basic link (also referred to as the permanent link). What level is being tested? The tester should normally be set to Cat5e link or Class E link if Category 6 cable is being used. The results are stored electronically and must be in a format recognisable by the cable management software that comes with the tester. There are now numerous test standards and draft standards. The most influential is likely to be; IEC 61935 Generic specification for the testing of balanced generic cabling in accordance with ISO/IEC 11801 The tests required are; IEC 61935 Wire Map X Attenuation X; NEXT pair to pair X; NEXT Powersum X; ELFEXT air to pair X; ELFEXT Powersum X; Return Loss X; Propagation Delay X; Delay Skew X;DC Loop Resistance X. Cable length and ACR are also useful additions to this set of tests. Optical cables All that needs to be tested with short distance multimode optical cables is attenuation. This can be achieved by a device called a light source and power meter. This device will simply measure the absolute loss across the optical link. This then has to be compared with the design value of attenuation. If the tested value is less than the design value then the link can be seen to be acceptable. Optical Time Domain Reflectometers can give a great deal of information about optical fibres, but for short haul multimode fibre they are an expensive overkill that gives results that need expert interpretation. An OTDR remains an essential tool for fault finding. [edit]Step 10: Final thoughtsIs the design of the cabling system in-step with the LAN aspirations of the end user? For example, Cat5e is the minimum performance grade suitable for gigabit Ethernet. Standard Cat5 cable may not have sufficient delay skew performance for RGB video systems however. Cat 6 cabling will give a longer service life due to its higher performance, but at an initial higher cost. Some optical fibre LANs, e.g. gigabit Ethernet cannot transmit over the full distance allowed in standards based optical structured cabling. These LAN limitations have to be taken into account. The next generation of 10 gigabit Ethernet will need a new generation of optical fibre to make it work. The best way to ensure success in a structured cabling installation is to use properly trained people to design, implement and test the system. The RCDD qualification from BICSI is the only qualification which covers all aspects of structured cabling design and implementation. The above information is offered as a summary of ISO 11801 and related standards. It is not a definitive design guide and does not replace study and implementation of the Standards themselves. The publisher accepts no responsibility for inaccuracies or omissions. To purchase the full Standards go to your national standards body, e.g. British Standards Institution, Nederlands Normalisatie Instituut etc. or ISO. [edit]Examples[edit]LinksMore information on Network Infrastructures at ITtoolbox Related White Papers and WebcastsRevolutionizing Enterprise Storage Infrastructure with Enterprise Flash TechnologyOptimizing Data Quality in the Enterprise: How to Tackle Your Bad InformationThe Real World Benefits of SAP Safeguarding ServicesShow more White PapersRelated ContentAssessing Technology Infrastructure (Blogs)802.11 (Wiki)Telecommunications (Groups)The Telecommunications Industry Overview: Version 3 (Training)CISSP Domain: Telecommunications and Network Security (Training)Cisco SWITCH 1.0: Integrating Wireless LANs into a Campus Network (Training)Jobs by * IT Operations Manager- GRID - Burlington MA * SAP Conference Producer - Dedham MA * Lead Business Architect - San Antonio TX
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Bottom of FormData CablesWhat are Data Cables?
The term data cables often refers to the range of electrical cables found in a structured cabling network called Category cables. Found linking data cabinets to individual wall sockets in a network, these twisted pair copper data cables have developed over the years from Category 3 Cable to the high performance Category 7 Cable. With advances in technology, Category 3 data cables now have limited use, Category 4 data cables are retired by modern standards and Category 5 data cables were upgraded to Cat 5E data cables in 2002. Most new and existing systems still install Cat 5E data cables and Cat 6 data cables (Cat 6A and Cat 7 do exist but the cost is still prohibitive for many installations – although Cat 7 data cable is increasingly being used in Germany). By what other names are Data Cables known?
As well as the term Category cables, data cables are also described as LAN cables, network cables and computer cables. When people talk about structured cabling, they are often referring to the data cables within the structured cabling network rather than simply the network itself. How is a typical Structured Cabling network constructed?In an office environment, a structured cabling network enables information to travel from a switch in the data room to a PC, via a series of data cables and structured cabling accessories. The main components in a structured cabling network are:1U UTP and 2U UTP Patch Panels: Cat 5E/Cat 6 compliant metal panels that enable data cables to be connected to a standard 19” data cabinet. 1U Metal Cable Management Bars: metal bars that fit into standard 19" data cabinets to keep the data cables from becoming tangled.Cat 5E Cable
Cat 6 Cable Cat 5E and Cat 6 Cables: data cables that transmit information from the data cabinets to the wall sockets (known as horizontal cabling).Back Box, Face Plate, Low Profile Module and LJ6C Module.Wall socket equipment: includes a box in the wall (Back Box), a socket covering (Face Plate) and a Low Profile Module or LJ6C Module – into which a Patch Lead can be inserted. The Face Plates can be Single Gang or Dual Gang Bevelled in shape and size and are used to hold the modules in place and cover the Back Box. The modules are then used to connect the horizontal data cables in the wall to an external Patch Lead (in both domestic and commercial properties).Cat 5E UTP Moulded and Booted Patch Leads (or cords): flexible Cat 5E data cables with a strain relief boot for transmitting data from the wall socket to the PC – and the switch to the data cabinet. What are Category 5E Data Cables?
Category 5E Cables are used widely in telecommunications systems and the building and construction industry – found in everything from Local Area Networks in offices and entertainment systems to cash (ATM) machines. These data cables are multipair (usually four pair) cables with class 1 twisted pair copper conductors and high density polyethylene (HDPE) insulation that meet the requirements of both ISO/IEC11801 and TIA/EIA 568B standards. Cat 5E cables are designed for transmission speeds of up to 1 gigabit per second (Gigabit Ethernet) and to support frequencies up to 100MHz. The standard Cat 5E Cable is Cat 5E UTP PVC Cable, which includes unshielded twisted pair conductors, and a PVC sheath. There are, however, a number of different Cat 5E data cables, designed to operate effectively in specific environments. A low smoke zero halogen (LS0H) UTP data cable, Cat 5E UTP LSZH Cable Cable, is available for use in public buildings – it emits low levels of Halogen gas when exposed to fire. Cat 5E FTP PVC Cable includes an Aluminium Foil (Al-Foil) screen around all of the pairs, which provides protection against external electromagnetic interference. Cat 5E PE FTP GSWB LSZH Cable is a Halogen-free data cable with an Aluminium Polyethylene Terephthalate (Al-Pet) screen and Galvanised Steel Wire Braid (GSWB) for locations requiring mechanical protection. And the UV resistant Cat 5E UTP PE External Cable, with its Polyethylene sheath (PE) to prevent water ingress, is designed for outdoor use.The only Cat 5E data cables that differ even further in construction are the Cat 5E 25 Pair UTP LSZH Cable and the Cat 5E 25 Pair UTP RBS Duct Grade Cable. Both data cables have class 1 solid plain copper conductors, SPE (Solid Polyethylene) insulation, a PE dummy core and a Mylar tape separator. The LS0H version has an LS0H sheath and the Duct Grade Cable has a PE and PP (Polypropylene) inner sheath and a PP sheath – for outdoor use in a duct. What is the difference between Cat 5E, Cat 6, Cat 6A and Cat 7 Data Cables?
Data cables from Cat 5E to Cat 7 are all high performance cables. The differences come in the level of performance (eg bandwidth) and the standard to which the data cable has been manufactured. Cat 6 LSZH Cable, for example, is very similar to Category 5E Cable, but it supports a frequency range of up to 250MHz and is manufactured to a higher standard. Cat 6A Cable has a bandwidth of 500mhz – and Cat 7 600mhz. Cat 6A and Cat 7 data cables are available in some markets but are not yet approved. Cat 7 Cable has been developed for high-end media systems and is mainly used in Germany at the moment.Why are the pairs in Data Cable twisted?
By twisting the pairs in data cables, the amount of electromagnetic interference (EMI) from external sources is reduced. If wires are placed next to each other in parallel this also leads to cross talk – signal interference between the cables. Twisting also prevents this from happening. |