Networking Cables Networking Cable is the medium through which information usually moves from one network device to another. There are several types of cable which are commonly used with LANs. In some cases, a network will utilize only one type of cable, other networks will use a variety of cable types. The type of cable chosen for a network is related to the network's topology, protocol, and size. Understanding the characteristics of different types of cable and how they relate to other aspects of a network is necessary for the development of a successful network.
Types of Networking Cables 1. Twisted Pair: Twisted Pair Cabling is a form of wiring in which pairs of wires (the forward and return conductors of a single circuit) are twisted together for the purposes of canceling out electromagnetic interference (EMI) from other wire pairs and from external sources. This type of cable is used for home and corporate Ethernet networks. There are two types of twisted pair cables: Shielded, Unshielded.
Figure 1
UTP & STP
Unshielded Twisted Pair (UTP) Cable: The quality of UTP may vary from telephone-grade wire to extremely high-speed cable. The cable has four pairs of wires inside the jacket. Each pair is twisted with a different number of twists per inch to help eliminate interference from adjacent pairs and other electrical devices. The tighter the twisting, the higher the supported transmission rate and the greater the cost per foot. The EIA/TIA (Electronic Industry Association/Telecommunication Industry Association) has established standards of UTP and rated six categories of wire (additional categories are emerging). Shielded Twisted Pair (STP) Cable: Although UTP cable is the least expensive cable, it may be susceptible to radio and electrical frequency interference (it should not be too close to electric motors, fluorescent lights, etc.). If you must place cable in environments with lots of potential interference, or if you must place cable in extremely sensitive environments that may be
Networking Cables susceptible to the electrical current in the UTP, shielded twisted pair may be the solution. Shielded cables can also help to extend the maximum distance of the cables. Shielded twisted pair cable is available in three different configurations:
Each pair of wires is individually shielded with foil. There is a foil or braid shield inside the jacket covering all wires (as a group). There is a shield around each individual pair, as well as around the entire group of wires (referred to as double shield twisted pair).
2. Coaxial Cable: First invented in the 1880s, "coax" was best known as the kind of cable that connected television sets to home antennas. Coaxial cable is also a standard for 10 Mbps Ethernet cables. When 10 Mbps Ethernet was most popular, during the 1980s and early 1990s, networks typically utilized one of two kinds of coax cable - thinnet (10BASE2 standard) or thicknet (10BASE5). These cables consist of Figure 2 Co-axial Cable an inner copper wire of varying thickness surrounded by insulation and other shielding. Their stiffness caused network administrators difficulty in installing and maintaining thinnet and thicknet. 3. Fiber Optic Cable: Fiber optic cabling consists of a center glass core surrounded by several layers of protective materials). It transmits light rather than electronic signals eliminating the problem of electrical interference. This makes it ideal for certain environments that contain a large amount of electrical interference. It has also made it the standard for connecting networks between buildings, due to its immunity to the effects of moisture and lighting. Fiber optic cable has the ability to transmit signals over much longer distances than coaxial and twisted pair. It also has the capability to carry information at vastly greater speeds. This capacity broadens communication possibilities to include services such as video conferencing and interactive services. The cost of fiber optic cabling is comparable to copper cabling; however, it is more difficult to install and modify. 10BaseF refers to the specifications for fiber optic cable carrying Ethernet signals.
Networking Cables
Figure 3 Fibre Optic
Cable
The center core of fiber cables is made from glass or plastic fibers. A plastic coating then cushions the fiber center, and kevlar fibers help to strengthen the cables and prevent breakage. The outer insulating jacket made of teflon or PVC. 4. USB Cables: Universal Serial Bus (USB) cables connect a computer with a peripheral device (keyboard or mouse) rather than to another computer for networking. However, special adapters (sometimes called dongles) also allow connecting an Ethernet cable to a USB port indirectly. USB cables feature twisted-pair wiring.
Figure 4 USB
Cable
5. Serial and Parallel Cables: Because many PCs in the 1980s and early 1990s lacked Ethernet capability, and USB had not been developed yet, serial and parallel interfaces that are obsolete on modern computers were sometimes used for PC-to-PC networking. So-called null model cables , for example, connected the serial ports of two PCs enabling data transfers at speeds between 0.115 and 0.45 Mbps. 6. Ethernet (Crossover) Cable: Null modem cables are one example of the category of crossover cables. A crossover cable joins two network devices of the same type, such as two PCs or two network switches. The use of Ethernet crossover cables was especially common on older home networks years ago when connecting two PCs directly together. Externally, Ethernet crossover cables appear nearly identical to ordinary (sometimes also called straight-through), the only visible difference being the order of color-coded wires appearing on the cable's end connector. Manufacturers typically
Networking Cables applied special distinguishing marks to their crossover cables for this reason. Nowadays, though, most home networks utilize routers that have built-in crossover capability, eliminating the need for these special cables.
Figure 5 Colour Coding for Ethernet Cable
Figure 7 Types
Figure 6 Difference b/w Ethernet Cable
of Cable n Speed
Networking Cables 7. Patch Cable: A patch cable is an electrical or optical cable used to connect one electronic or optical device to another for signal routing. Devices of different types (e.g. a switch connected to a computer, or a switch connected to a router) are connected with patch cords. It is a very fast connection speed. Patch cords are usually produced in many different colors so as to be easily distinguishable,[2] and are relatively short, perhaps no longer than two meters.