Data cabling is an important data transmission channel for an enterprise, not just a cable. A reliable and fast data cabling solution is a prerequisite for business success.

Data cables carry electronic information from a data source to a destination.  Currently, the types of data cables widely used in computer and telecommunication systems are mainly copper cables and fiber optics.

The Golden Rules of Data Routing

If the enterprise has improper wiring design and installation in practice, many problems that are difficult to predict may appear.

Here are some rules to consider when planning a structured cabling system:

• Network transport needs will never get smaller or simpler.
• Build a cabling system that can accommodate both voice and data.
• Always install more cables than are currently required. Those extra cables and ports will come in handy someday.
• Using structured cabling standards when building a new cabling system effectively avoids anything proprietary!
• Quality matters! Use high-quality wiring and wiring components. Cabling is the foundation of a network, and if it fails, everything else becomes irrelevant. You'll see a range of different pricing for a given grade or class of cabling, but a high price doesn't necessarily mean the highest quality. Buy based on a manufacturer's reputation and proven performance, not just price.
• Don't skimp on the setup fee. Even quality components and cables must be installed correctly; poor construction will ruin more than one wiring installation.
• Planning for higher speed technology than is generally available today. Just because some high-bandwidth Ethernet doesn't seem necessary today, doesn't mean it won't be necessary in the next 5 years.
• Documentation, while tedious, is a must when setting up a cabling system.

Always use reliable cabling

It can be said that we cannot stress enough the importance of reliable cabling. Some recent studies show that:

• Data cabling typically accounts for less than 10 percent of the total network infrastructure cost.
• Typical cabling systems have a useful life of 16+ years. Cables are probably the second longest-lived asset many businesses have (the first being the building's structure).
• Nearly 70 percent of all network-related problems are due to poor cabling techniques and cable assembly problems.

If the correct category or grade of cable is installed, most cabling problems are usually related to patch cords, connectors, and termination techniques. The permanent link portion of the cable (the part on the wall) is unlikely to be a problem unless it was damaged during installation.

Of course, these are facts we already know based on past experience. Many businesses often spend a great deal of time troubleshooting non-standard, poorly designed, poorly documented and improperly installed cabling systems. We have seen a lot of money wasted on installing additional cabling and cabling infrastructure support that should have been part of the original installation.

So no matter how you look at it, cabling is the foundation of networking.

Data Routing and Speed

In the past few years, there have been huge advances not only in network technology, but also in the demand for network technology. Over the past 30 years we have seen 10Mb Ethernet, 16Mb Token Ring, 100Mb FDDI (Fiber Distributed Data Interface), 100Mb Ethernet, 155Mb ATM (Asynchronous Transfer Mode), 655Mb ATM, 1Gb Ethernet, 2.5Gb Emergence of standards such as ATM, 10Gb Ethernet, 40Gb Ethernet, and 100Gb Ethernet. Network technology designers are already planning technologies that support data rates as high as 400Gbps, or even 800Gbps.

The average number of nodes on a network segment decreased dramatically, while the number of applications and the amount of data transferred increased dramatically. Applications are becoming more complex, and the amount of network bandwidth required by a typical user is increasing. Need the bandwidth offered by some new ultra-fast networking applications such as 10Gb Ethernet today? Maybe not desktops, but network backbones already take advantage of them.

Does the fact that software applications and data place ever greater demands on networks have anything to do with data cabling? One might think that the problem has more to do with network interface cards, hubs, switches, and routers, but as data rates increase, so does the need for higher levels of performance from the cables.

Type of transmission medium

There are four main types of communication media (cables) used in data networks today:

• Unshielded Twisted Pair (UTP)
• Shielded or shielded twisted pair (STP or ScTP)
• coaxial cable
• Optical Fiber (FO)

It is important to distinguish between backbone cables and horizontal cables. Backbone cables connect servers, switches, routers and other network equipment, and connect the computer room and telecommunications room. Horizontal cables run from the telecommunications room to wall sockets. For new installations, stranded fiber optic cables are basically generic backbone cables. For horizontal, UTP accounts for 85% of the typical application market. However, newer fiber-based network topologies offer increasing advantages over UTP.

twisted pair cable

In traditional installations, the most economical and widely installed cabling today is twisted pair cabling. Not only is twisted pair less expensive than other media, but installation is also simpler, and the tools required for installation are less expensive. Unshielded Twisted Pair (UTP) and Shielded Twisted Pair (STP) are the two main types of twisted pair in the market today. Screened Twisted Pair (ScTP) is a variant of STP.

Unshielded Twisted Pair (UTP)

Although it has been used in telephone systems for many years, unshielded twisted pair (UTP) for LANs first became common in the late 1980s with the advent of the twisted pair-based Ethernet and 10Base-T standards. UTP is cost-effective and easy to install, and its bandwidth capabilities are constantly improving.

Shielded Twisted Pair (STP)

Shielded Twisted Pair (STP) cabling was first popularized by IBM when it introduced the data cabling type classification. Although more expensive to purchase and install than UTP, STP has some distinct advantages. The current ANSI/TIA-568-C cabling standard recognizes IBM Type 1A horizontal cables, which support frequencies up to 300MHz, but are not recommended for new installations. STP cables are less susceptible to external electromagnetic interference (EMI) than UTP cables because all pairs are well shielded.

Screened Twisted Pair  (ScTP  -  Screened  Twisted  Pair)

The cable type recognized in the ANSI/TIA-568-C standard is Screened Twisted Pair (ScTP) cable, which is a hybrid of STP and UTP cables. ScTP cables consist of four pairs of unshielded 24 AWG, 100 ohm wires surrounded by a foil shield or wrap wire and a drain wire for grounding purposes.

For this reason, ScTP is sometimes referred to as Foiled Twisted Pair (FTP) because the foil shield surrounds all four conductors. This foil shield is not as bulky as the braided copper braid sheath used in some STP cabling systems such as IBM Type 1 and Type 1A. ScTP cables are essentially STP cables with the individual pairs unshielded; the shield may also be smaller than some types of STP cabling. In short, ScTP is a compromise between cost and anti-interference.

Fully shielded twisted pair (S/STP or S/FTP)

S/STP cabling, also known as fully shielded twisted pair (S/FTP), consists of four individually shielded pairs of 24 AWG, 100 ohms, surrounded by an outer metal shield covering the entire shielded copper pair set. This type of cabling provides the best protection from interference from external sources and also eliminates alien crosstalk, thus offering the greatest potential for higher speeds.

Category 7 and 7A are S/STP cables standardized in ISO 11801 Ed2.2. Provides 600 and 1000MHz of usable bandwidth, respectively. Its intended use is for 10 Gigabit Ethernet, 10GBase-T applications. S/STP cables have four individually shielded conductor pairs.

optic fibre cable

Until 1993, it seemed that in order to move toward the future of desktop computing, enterprises had to install fiber optic cables directly to the desktop. Surprisingly, copper cable (UTP) performance continues to outperform expectations.

single mode fiber optic cable

Single-mode fiber optic cables are most commonly used by telecommunications companies in transcontinental link and data installations as the backbone cables that interconnect buildings. Single-mode fiber optic cables are not used as horizontal cables to connect computers to hubs, nor are they often used as cables to connect telecommunications rooms to main equipment rooms. Light in single-mode fiber optic cables travels directly along the fiber and is not reflected by the surrounding cladding as it travels. Typical single-mode wavelengths are 1310 and 1550 nm.

Multimode Fiber Optic Cable

Multimode fiber optic (MMF) cables are typically fiber optic cables used in networking applications such as 10Base-FL, 100Base-F, FDDI, ATM, Gigabit Ethernet, a10 Gigabit Ethernet, 40 Gigabit Ethernet, and 100 Gigabit Ethernet optics for horizontal and backbone cables. Multimode cables allow more than one mode of light (part of a pulse of light) to travel through the cable. Typical wavelengths of light used in multimode cables are 850 and 1,300 nanometers.

coaxial cable

Once the most widely used cable type in the networking business, coaxial cable specifications are now contained in ANSI/TIA-568-C.4. It is still widely used in CCTV and other video distribution, and is widely used in broadband and cable TV applications. However, it is being phased out in the data networking arena. Coaxial cable is difficult to lay and is usually more expensive than twisted pair cable. However, to protect the coaxial cable, it offers huge bandwidth and is not as susceptible to external interference as UTP. Overall installation costs may also be lower than other cable types because the connectors take less time to install.

Materials used for wire insulation

Currently, a variety of insulating materials exist, including polyolefins (polyethylene and polypropylene), fluorocarbon polymers, and PVC.

Manufacturers select materials based on material cost, flammability rating, and desired transmission characteristics. Materials such as polyolefins are inexpensive and have excellent transmission properties, but they are flammable, so they must be combined with materials with better flame ratings. It's important to remember this: don't focus on specific material. What matters is the material system chosen by the manufacturer. Manufacturers will choose insulation and sheathing materials that work together based on the delicate balance of fire resistance, transmission performance and economics.

The most common material used to insulate wire pairs in Category 5e and higher plenum-rated cables is fluorocarbon polymer. The two fluorocarbon polymers used are fluorinated ethylene-propylene (FEP) and perfluoroalkoxy (PFA).

These polymers were originally developed by DuPont and are sometimes named after its trademark Teflon. The most common and desirable of these materials is FEP. Over the past few years, the demand for plenum-rated cables has outstripped the supply of available FEP. During times of FEP shortages, category 5e supercharged designs emerged, replacing one or more pairs of wires with another material.

Additionally, some marginal performance instances have emerged in the UL-910 burn test of plenum cables. These concerns, combined with the increased availability of alternatives such as FEP and MFA, have driven the development of these designs.

insulation color

The insulation around each wire in UTP cables is color coded. Standardized color codes help cable installers ensure that each wire is properly connected to the hardware. For example, in the United States, color codes are based on 10 colors. Five of these are used on tip conductors and five are used on ring conductors. Combining tip colors with ring colors creates 25 possible unique pairing combinations. Therefore, telephone cables have used 25 pairs for decades.

twine

When you cut a UTP communications cable, you'll notice that the individual conductors of a pair of wires are twisted around each other. At first, you may not realize the importance of these twists.

Did you know that in Category 5e cables, a pair of untwisted wires longer than half an inch can adversely affect the performance of the overall cable?

Wire Gauge

Copper wire diameter is usually measured in units called AWG (American Wire Gauge). Contrary to many other measurement systems, as the AWG number gets smaller, the wire diameter actually gets larger; therefore, AWG 24 wire is smaller than AWG 22 wire. Larger wires are useful because they have greater physical strength and lower resistance.

The challenge for cable designers is to use the smallest possible diameter wire (reducing cost and installation complexity) while maximizing the performance of the wire to support the necessary power levels and frequencies.

Type 5e UTP is always 24 AWG; IBM Type 1A is usually 22 AWG. The jumper wires are probably 26 AWG, especially category 3 jumper wires. The development of higher performance cables such as Category 6 and 6A has resulted in 23 AWG being frequently replaced by 24 AWG.

The table below shows the 22, 23, 24 and 26 AWG sizes and the corresponding diameter, area and weight per kilometer.

The dimensions in the table above were developed over 100 years ago. Since then, the purity and electrical conductivity of copper have improved due to better copper processing techniques. Specifications covering the design of communications cables forego the actual size of the wires. The real concern is not the size of the wire, but how well it performs, especially with regard to resistance (measured in ohms). The AWG standard indicates that 24 AWG wire has a diameter of 0.0201", but depending on the properties of the material, the actual diameter of the wire may be slightly smaller or larger (but usually smaller).

Solid and Stranded Conductors

UTP cables used as horizontal cables (either permanent or in-wall) have solid conductors, as opposed to patch cords and cables run for short distances, which typically have stranded conductors. A stranded wire consists of many smaller wires intertwined to form a single wire.

cable length

The longer the cable, the less likely it is that the signal will be fully delivered to the end of the cable due to noise and signal attenuation. But realize that with LAN systems, the time it takes for the signal to reach its destination is also critical.

Cable design engineers are now measuring two additional performance parameters of cables: propagation delay and delay skew. Both of these parameters are related to the speed at which electrons travel through the cable and the length of the wire pairs in the cable.