Types Of Communications Media

Four major kinds of communications media (cabling) are ready for data networking today: unshielded twisted-pair (UTP), shielded or screened twisted-pair (STP or ScTP). Coaxial, and fiber-optic (FO). It is important to distinguish between backbone cables and horizontal cables. Backbone cables connect network equipment such as servers, switches, and routers and connect equipment rooms to the wall outlets. For the horizontal, UTP accounts, for 85 percent of the market for typical applications. Most of the focus of this book are on UTP cable; however, newer fiber optic-based network topologies are included as well, as they are providing additional and more advantages over UTP.

Twisted-pair cable

In traditional installations, the most economical and widely installed cabling today is twisted-pair wiring. Not only is twisted-pair wiring less expensive than other media. Installation is also simpler, and the tools needed to install it are not as costly. Unshielded twisted-pair and shielded twisted-pair are two primary kinds of twisted-pair on the market today. Screened twisted-pair is a variant of STP.

Unshielded Twisted-pair (UTP)

Though it has been used for a long time for telephone systems, unshielded twisted-pair (UTP) for LANs first became widespread in the late 1980s with the advent of Ethernet over twisted-pair wiring and the 10Base-T standard. UTP is cost-effective and easy to configure, and its bandwidth capabilities are continually being enhanced.

Shielded Twisted-pair (STP)

Shielded Twisted-pair (STP) cabling was first made popular by IBM when it introduced type classification for data cabling. Though more costly to buy and install than UTP, STP offers some distinct advantages. The current ANSI/TIA-568-C cabling standard recognizes IBM Type 1A horizontal cable, which supports frequent states of up to 300MHz, but does not commend it for new installations. STP cable becomes less susceptible to external electromagnetic interference (EMI) than UTP cabling because all cable pairs are properly shielded.

Single-Mode Fiber Optic cable

Single-mode fiber optic cable is most often used by telephone companies in transcontinental links and in data installations as backbone cable interconnecting buildings. Single-mode fiber optic cable is not included in horizontal cable to connect computers to hubs and is not often used as a cable to interconnect telecommunications rooms to the main equipment room. The light in a single-mode cable travels straight down the fiber (as showed in Figure 1.5) and does not bounce off the surrounding cladding as it travels. Typical single-mode wavelengths are 1310 and 1550 nanometers.

Fiber optic cabling is used for a huge number of places as it is the fastest medium for the transmission of data. It's widely used in computer communication. The principal applications of fiber optics are in television cable services, industrial plants and utility companies. However, it is applied with utmost care and precision for better results.

In fiber optic communication systems, lasers are used to transmit messages in numeric code by flashing on and off at high speeds. This code can constitute a voice or an electronic file containing, text, numbers, or illustrations, all by using fiber optics. The light from various lasers is added together into a single fiber optic enabling a large number of currents of data to move a single fiber optic cable at once. This data will cross the fiber optics and into interpreting devices to convert the messages back into the form of its original signals. Industries also use fiber optics to be measured temperatures, pressure, acceleration and voltage, among an assortment of additional uses.

Nowadays there are a lot of fiber optic companies. Fiberstore is a fiber optic manufactures, which sells a broad portfolio of optical communication products, including passive optical network, or PON, subsystems, optical transceivers, etc.