Chapter 4: Network Media, Connectors, and Their Characteristics
Chapter Outline
1. On the Test
a. 1.3: Specify the characteristics (e.g., speed, length, topology, cable type, etc.) of the following: 802.3
(Ethernet) standards; 10BASE-T; 100BASE-TX; 10BASE-2; 10BASE-5; 100BASE-FX; Gigabit
Ethernet.
b. 1.4: Recognize the following media connectors and/or describe their uses: RJ-11; RJ-45; AUI; BNC; ST;
SC.
c. 1.5: Choose the appropriate media type and connectors to add a client to an existing network.
d. 4.12: Given a network troubleshooting scenario involving a writing/infrastructure problem, identify the
cause of the problem (e.g., bad media, interference, network hardware).
2. Understanding Ethernet Standards
a. The IEEE 802 standard addresses hardware that interacts with the Physical and Data Link layers of the
OSI Model.
b. Specifically, it establishes standards for components such as network interface cards, wide area
networking components, and the components used to make twisted pair and coaxial cable networks.
c. The two most common media are twisted pair wire and coaxial cable.
3. Twisted Pair Cable
a. Twisted pair wire, the same type used to connect telephones, is used to connect network devices
together. UTP contains four wire pairs (eight wires total).
b. Each type includes at least two pairs of insulated copper wires that are twisted together and housed in a
plastic sheath.
c. Higher categories have more twists per foot, which provides for better throughput and less chance of
crosstalk or outside electromagnetic interference (EMI).
d. For 10Base-T networks, the twisted pair cabling must be rated at a minimum of Category 3, although
Categories 4 and 5 may also be used.
e. Twisted pair wire used in data networks can be either unshielded (UTP) or shielded (STP).
f. The sheath or exterior covering of the cable pairs can be either plenum grade or non-plenum grade.
g. Twisted pair cabling uses RJ-45 connectors.
4. 10Base-T
a. Shielded or unshielded twisted pair cable is used.
b. RJ-45 connectors are used to terminate one or more ends of the cable. The cable may also be terminated
at a punch-down block or in the back of a patch panel.
c. Each station has its own network cable and it is not shared with any other stations.
d. Network speeds are 10Mbps.
e. A maximum of 1024 stations are allowed per network.
f. The maximum distance of a cable run is 100 meters (328 feet).
g. The shortest length of cable must be at least 0.6 meters (2 feet).
5. 100Base-T
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a. 100Base-T Ethernet works just like regular Ethernet except that it can obtain data transfer speeds up to
100Mbps.
b. Fast Ethernet can be divided into two categories: 100Base-TX and 100Base-T4. Both 100Base-TX and
100Base-T4 work with twisted pair cable.
6. 100Base-T4 can attain data transfer speeds up to 100Mbps over Category 3 cable. 100BaseT4 uses four pairs
of wiring (all eight wires)
7. 100Base-TX
a. 100Base-TX requires Category 5, unshielded twisted pair cable.
b. All associated networking hardware, such as patch panels and connectors, must comply with Category 5
standards.
8. 10Base-2 - Thin Coaxial Cable
a. Coaxial cable has two conductors, a center copper core that is shrouded by insulating Teflon or plastic
foam, and a foil wrap or a braided metal shield that covers the insulating plastic foam. The inner core
carries the electrical signals while the outer foil wrap shields against noise.
b. Coaxial cable is commonly used in a bus configuration.
c. 10Base-2 networks use RG-58 cable (Thinnet). Cable types RG 58 A/U or RG 58 C/U are commonly
used.
d. Each end of the segment must be equipped with a 50-ohm terminating resistor.
e. Pieces of coaxial cable may be no shorter than 0.5 meter (1.64 feet) in length. This means that the
minimum spacing between network connections must be at least 0.5 meter.
f. Thinnet segments may be a maximum of 185 meters (607 feet) long.
9. 10Base-5 - Thick Coaxial Cable
a.
b.
c.
d.
e.
f.
g.
h.
i.
j.
Thick coaxial cable, also known as Thicknet (RG-8/RG-11), is commonly used in 10Base-5 networks.
Thicknet is well suited for network backbones or for connecting hubs.
Uses RG-8 or RG-11 cable, which has a solid center conductor
Uses a thick (0.4-inch diameter) and inflexible coaxial cable. The outer casing of the cable may be
polyvinyl chloride (PVC), which will be yellow in color, or Teflon, which will be an orange or brown
color.
Plenum cable may be required to meet fire regulations.
Must be terminated at each end with 50-ohm terminators and should be grounded at one end for
electrical safety reasons
A maximum of 100 devices may be attached to a segment.
Pieces of Thicknet may be no shorter 2.5 meters. This means that the minimum spacing between
network connections must be at least 2.5 meters.
Each segment has a maximum length of 500 meters, which may be extended with repeaters. A
maximum of five segments may be used.
Transceivers are used to attach nodes to the cable.
10. Fiber-Optic Cabling
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a. Instead of using copper wire to transmit electrical signals, fiber-optic cabling uses light-conducting glass
fibers as its core.
b. Data is then transmitted either through pulses of light that are sent by a laser or light-emitting diodes
(LED).
c. There are several different types of fiber optic cabling:
i. Singlemode: Contains a single, tiny strand of fiber-optic glass, usually 7.1 or 8.5mm in diameter.
Singlemode fiber is typically used in telephone applications, cable television, or as a backbone.
ii. Multimode: In multimode fiber, the core is usually 62.5mm in diameter, much larger than that
used by singlemode. Multimode can handle many rays at once, making it ideal for voice and
data applications. Multimode cable is the most commonly used in computer networks.
iii. Simplex fiber: Simplex is a cable containing a single strand of fiber.
iv. Duplex fiber: Duplex is a cable with two strands of fiber bound together in separate jackets.
d. Must follow the prescribed bend radius when installing (i.e., if the cable is bent too sharply, it will
break)
e. Difficult to terminate; there are several types of connectors in use. Must ensure you purchase the correct
connectors, especially when working in an area where fiber has already been installed.
f. Fiber-optic cable is expensive. When buying in bulk, expect to pay about $1.00 per foot.
g. Fiber-optic devices, such as network cards and media converters, must also be used.
h. Very secure since data is transmitted using pulses of light rather than electrical signals.
i. Resistant to EMI since it does not transmit electrical signals.
j. Maximum length is measured in miles, approximately 2.4 (or 4 kilometers).
k. Does not attenuate very quickly.
l. The most common connectors used for fiber-optic cabling are either ST or SC connectors.
11. 100Base-FX
a. 100BaseFX uses fiber-optic cabling to transfer data at 100Mbps, while maintaining Ethernet standards.
b. Advantages:
i. It provides a fast, reliable, and secure connection
ii. It is highly resistant to EMI.
iii. It can transmit up to approximately 4 kilometers (approximately 2.4 miles).
c. Disadvantages
i. It is very expensive, especially when compared to 100Base-T using copper wiring.
ii. It is more difficult than copper to install and terminate.
iii. You must also purchase networking hardware with fiber connections or purchase media
converters.
12. Gigabit Ethernet
a. Gigabit Ethernet is a transmission technology that is based on Ethernet standards.
b. Provides a data transfer rate of 1 billion bits per second (one gigabit)
c. Frequently used as the backbone in large-enterprise networks
d. Fiber-optic cable is the media used primarily on Gigabit Ethernet networks, although copper cable may
be used for very short distances.
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