Network Cabling

---

There are over 2,500 types of cable in use to connect computers and peripherals. The majority of computers in use today still use some type of wire or cable to transmit data from one system to another. There are three primary types of network cables in use that you need to be familiar with:

• Coaxial

• Twisted pair

• Fiber optic

Each of these cable types has different characteristics that set them apart from the others such as cost, distance limitations, data transfer methods, data transfer rates, and installation methods used.

Coaxial Cable

Coaxial cable is separated into two distinct categories: thicknet and thinnet.

Thicknet

Thicknet coaxial cable, otherwise known as 10Base5, is approximately 0.5 inches thick; it is a heavy type of cable with a copper core that was used with early mainframe computers and early networks. Thicknet coaxial still exists but is very limited in its ability to achieve high data transfer rates that are needed to support today’s bandwidth-hungry computers and applications.

Thicknet coax cable has the ability to carry 10 megabits of data a total distance of 500 meters or approximately 1,500 feet. Thus, the naming convention scheme of 10Base5 has been established for coax cable. In other words, 10 megabits of information can travel over a baseband medium or base a total of 500 meters; 5 multiplied by 100 equals 1,500 feet but the true measurement is closer to 1,640 feet. The naming convention drops the last two 0’s.

Thicknet coaxial cable was and sometimes still is used as a backbone connection that connects to a small thinnet cable by use of a Vampire Tap and an AUI (Attachment Unit Interface) connector.

Thinnet

Thinnet coaxial cable, otherwise known as 10Base2, is approximately 0.25 inches thick. It is a thinner, more flexible type of coaxial cable that is usually connected directly to a NIC with a BNC or BNC T-connector. Thinnet is much easier to install and work with than thicknet. However, thinnet only carries a data signal the distance of 185 meters or approximately 607 feet.

Both thicknet and thinnet coaxial can make up a network referred to as a bus network. A bus network must be terminated at both ends of a cable or the bus network will fail. Thus, thicknet and thinnet both require terminators at both ends of their cable.

Twisted-Pair Cable

Twisted-pair cable, or TP for short, arose from the need to replace the distance and other limitations associated with coaxial type cable. TP is referred to as 10BaseT. Once again, the 10 is for the transmission rate of data, the base refers to a baseband media type, and the T refers to the twisted pair or wiring twists in the cable itself.

There are two types of twisted pair wiring: shielded twisted pair (STP) and unshielded twisted pair (UTP).

Shielded Twisted Pair (STP)

Shielded twisted pair is basically the same type of wire as unshielded twisted pair with the exception that STP uses a woven copper braided shielding and foil wrapping that protect the twisted wire pairs from outside interference such as EMI (Electro Magnetic Interference). This also allows an STP wire to be less susceptible to crosstalk from other wires. STP is more expensive than unshielded twisted pair based on its extra protection and ability to transmit a data signal over a longer distance than UTP.

Unshielded Twisted Pair (UTP)

Unshielded twisted pair, or UTP for short, is also a 10Mbps baseband cable. UTP, generally referred to as 10BaseT, is the most common type of Ethernet cable in use today and is found mostly in star typology networks. UTP in its simplest form is two insolated copper wires that can carry a data signal 100 meters or approximately 328 feet.

There are five categories for UTP wiring as specified by the Electronics Industries Association and the Telecommunications Industries Association (EIA/TIA) to keep wiring standards uniform. They are as follows:

• Category 1 (CAT1): This is the original implementation of UTP used for telephone cable. It is capable of transmitting voice but not data. This type of phone wire was installed prior to the mid-1980s.

• Category 2 (CAT2): This UTP cable type is made up of four twisted pairs of wires. It is cable of transmission rates up to 4Mbps.

• Category 3 (CAT3): This UTP cable can transmit data up to 10Mbps. It has four twisted pairs that are twisted three times per foot.

• Category 4 (CAT4): This UTP cable is capable of data transmissions up to 16Mbps. It has four twisted pairs of wire.

• Category 5 (CAT5): This UTP cable is capable of data transmission rates of up to 100Mbps. It is also made of four twisted pairs of wire. CAT5 UTP is also referred to 100BaseT or 100BaseTX. It carries a data signal 100 meters or approximately 328 feet. It is the most popular UTP cable in use today. CAT6 and CAT7 UTP are also available today and offer transmission speeds up to 155MBps and 1GBps, respectively.

Twisted Pair Connectors

There are two types of UTP connectors you should be familiar with: RJ-11 and RJ-45. An RJ-11 phone connector is used for early categories of UTP to connect a modem to a typical phone jack or your phone to a phone jack. In technical circles, an RJ-11 wire is a simple phone wire that houses four wires or connections.

An RJ-45 connector is the most common type of TP data cable connector in use. It houses eight wire traces. The RJ-45 connector on one end of a TP wire plugs into a network interface card that is installed into a system. The RJ-45 connector on the other end of the TP cable plugs into a network hub, router, or RJ-45 wall jack.

Crossover Cable

A crossover cable is a type of Ethernet TP cable that is commonly used to connect computers in a peer-to-peer fashion. The crossover cable switches the transmit and the receive lines of the cable, which allows two computers to communicate directly with each other without the use of a hub or router. If you want an inexpensive alternative to purchasing a hub, a crossover cable is the way to go to connect two computers.

Fiber-Optic Cable

Fiber-optic cable, otherwise known as 10BaseFL, is the network wire of choice. It is capable of extremely fast transmission rates over long distances without interference. A fiber-optic cable has a core that is composed of plastic or glass. A glass cladding or sheath covers the core. Finally, a Kevlar fiber jacket surrounds the entire wire. Data can be transmitted through a fiber-optic cable with a laser or LED (Light Emitting Diode) at a rate of 2Gbps or higher. The data signal on a fiber wire can travel up to a distance of 100 kilometers or 60 miles depending on which technology is being implemented with the fiber and if a repeater is used.

Fiber optic cables use special ST and SC type connectors to attach to network interface cards and fiber optic ports. These connectors are precisely crafted and specially designed to suit fiber-optic cable connection requirements.

Fiber-optic cable needs great care and consideration when being installed. Specially trained and certified fiber installers are usually empowered to carry out this task. Because of its high transmission speeds and specialized installation methods, fiber-optic technology is quite expensive.

Note 

Fiber-optic cable is much more difficult to tap into than other types of network cable. In other words, it is considered the most secure type of network cable. Special equipment and skilled hands are required to carry out such a task. This is not the case with twisted pair and coaxial types of cable.

Refer to Table 4.1 for a comparison chart of the major networking cables described in this chapter.

Table 4-1: Cable Comparison Chart

Cable Type	Transmission Speed	Distance
10BaseT	10Mps	100M/328ft
10BaseT2	10Mps	185M/607ft
10BaseT5	10Mps	500M/1,500ft
100BaseT	100Mps	100M/328ft
Fiber	100Mps to 2Gps	100K/60 miles

---