<p> Cabling Basics February 22 (Day); February 19 (Night)</p><p>. Coaxial cable: o Coaxial cable, called “coax” for short, was the cable of choice for Ethernet networks throughout the 1970s and 1980s. o Coaxial cable consists of a central copper core that carries data. It is surrounded by plastic insulation, braided metal shielding, and an outer jacket. Because it has a lot of shielding, it has a lot of resistance to noise. o It has major drawbacks: . It is expensive. . It is thick and inflexible. o It comes in two varieties: . Thicknet is 1 cm thick and the original Ethernet medium. . Thinnet is .64 cm thick which made it more flexible and easier to install.</p><p>Thicknet on left; Thinnet on right</p><p>. Twisted-pair cable: o Twisted-pair cable consists of color-coded pairs of insulated wires. Every two pairs wrap around each other to form pairs and all of the pairs are encased in a plastic cover. . Pairs of wires carry signals in opposite directions, so that the two magnetic fields also occur in opposite directions and cancel each other out. This process is known as cancellation. . The more twists per foot or meter, the more resistant the pair will be to crosstalk. The number of twists per foot is known as the twist ratio. . High twist ratios indicate higher quality and lead to more attenuation. . All twisted-pair cable falls into one of two categories: STP (shielded twisted pair) or UTP (unshielded twisted pair). o Shielded twisted-pair (STP) cable consists of twisted pair wires that are not only individually insulated, but also surrounded by a shielded made of a metallic substance such as foil.</p><p>Shielded twisted-pair cable; notice the foil o Unshielded twisted-pair (UTP) cabling consists of one or more insulated wire pairs. There is no additional shielding for the twisted pairs.</p><p>Unshielded twisted-pair cable</p><p>. UTP is less expensive and less resistant to noise.</p><p>. Categories of UTP:  Cat 1 – used for telephone communication  Cat 2 – transmits up to 4 Mbps  Cat 3 – transmits data up to 10 Mbps; used in both Ethernet or Token Ring  Cat 4 – transmits data up to 16 Mbps; used in both Ethernet or Token Ring  Cat 5 – transmits data up to 100 Mbps; used by Ethernet  Cat 5e – higher grade of Cat5; transmit data up to 1000 Mbps; used by Ethernet  Cat 6 – transmit data up to 1000 Mbps; additional foil insulation to protect against noise; used by Ethernet  Cat 7 – in development . Fiber-optic cable: o Fiber-optic cable has a core of several glass or plastic fibers. Data is transmitted via pulsing light sent from a laser through the central fibers. . Surrounding the fiber is a layer of more dense glass known as cladding which reflects light back to the core.</p><p>. Ethernet Implementations: 10Base-5 10Base-2 – developed in 1980 – developed in 1985 – 10 represents max throughput of 10 Mbps – 10 represents max throughput of 10 Mbps – Base represents baseband transmission – Base represents baseband transmission – 5 represents the 500 m max cable length – 2 represents the 200 m max cable length – Used Thicknet – Used Thinnet</p><p>10Base-T 100Base-T – developed in 1990 – also known as “Fast Ethernet” – 10 represents max throughput of 10 Mbps – 100 represents max throughput of 100 Mbps – Base represents baseband transmission – Base represents baseband transmission – T indicates twisted pair – T indicates twisted pair – Uses Cat3 or higher – Uses Cat5</p><p>100Base-TX 1000Base-T – T represents twisted pair – also known as “Gigabit Ethernet” – X means it works in full-duplex – 1000 represents max throughput of 1000 – Base represents baseband transmission Mbps – has 200 Mbps throughput – Base represents baseband transmission – Uses Cat5 – T indicates twisted pair – Uses Cat5e or higher</p>