Ch. Two
network media-copper core cable
Summary
■ The three major classifications of network media are copper cable, fiber-optic
cable and wireless radio waves.
■ Electronic signals are classified as analog and digital. Analog and digital
signals differ by the shape of their waveforms.
■ In the analog signal, time affects the degree of the slope. In the digital signal,
time affects the duration of the voltage level.
■ Both analog and digital waves have a frequency measurement. Frequency is
the number of cycles that occur in 1 second and is measured in Hertz (Hz).
■ Attenuation is the loss of signal strength.
■ Interference is an unwanted signal that combines with and changes the
waveform of the original signal.
■ Latency is the amount of time it takes a signal to travel from its source to its
destination.
■ Bandwidth is a measurement of the ability of network media to carry data;
whereas, frequency is a measurement of the ability of network media to carry
an electronic signal.
■ Baseband is a method of transmitting a single frequency, using the entire
bandwidth of a cable.
■ Broadband is a method of transmitting multiple frequencies or data across a
cable at once.
■ Communication can occur in one of three modes: simplex, half-duplex, and
full-duplex. Simplex communication occurs in one direction only. Half-
duplex communication occurs in both directions, but not at the same time.
Full-duplex communication occurs in both directions at the same time.
■ Electrical energy that travels in only one direction is referred to as direct
current (DC).
■ Electrical energy that constantly reverses its direction of flow is referred to as
alternating current (AC).
■ Electrical resistance is the opposition to the flow of electrical energy.
Resistance is generally used to describe this effect in DC circuits.
■ Impedance is also the opposition to the flow of electrical energy, but it
expresses the amount of resistance encountered in an AC circuit.
■ Reflected loss is the amount of signal reflected from the far end, or receiving
end, of a cable.
■ The electrical phenomenon of a current-carrying conductor inducing current
in a cable of close proximity is called crosstalk.
■ Near-End Crosstalk is a measurement of crosstalk at the near end, or sending
end, of a cable.
■ Alien Crosstalk is crosstalk generated from network cables in close proximity
to each other.
■ The decibel (dB) is an electrical measurement that is used to express the
amount of power or energy gained or lost.
■ Far-End Crosstalk is a measurement of crosstalk at the far end, or receiving
end, of a cable.
■ Equal Level Far-End Crosstalk is a measurement of the negated effects of
cable attenuation caused by crosstalk.
■ Copper conductor wire size is based on its diameter and is expressed as
a size according to the American Wire Gauge AWG. The larger AWG the
number, the smaller the wire size.
■ Three common coaxial cable types that have been used for networking are
RG-6, RG-8 (thicknet), and RG-58 (thinnet).
■ Twisted pair cable is divided into seven categories. The categories are based on
the physical design and capabilities of the cable such as the maximum frequency
rating, the data rate that the cable is capable of, and number of twists per foot.
■ The IEEE 802.3 standard describes the characteristics of various Ethernet
technologies such as 10 Mbps, Fast Ethernet, Gigabit Ethernet, and 10 Gigabit
Ethernet.
■ An Auto-MDIX compliant device automatically reassigns the pin functions
so that a crossover cable is not required for communication.
■ Power over Ethernet (PoE) is a way of powering devices that consume small
amounts of electrical energy, approximately 13 watts at 48 volts, over network
cable.
■ Wiring faults include shorts, opens, reversed pairs, crossed pairs, and split pairs.
■ The three major classifications of network media are copper cable, fiber-optic
cable and wireless radio waves.
■ Electronic signals are classified as analog and digital. Analog and digital
signals differ by the shape of their waveforms.
■ In the analog signal, time affects the degree of the slope. In the digital signal,
time affects the duration of the voltage level.
■ Both analog and digital waves have a frequency measurement. Frequency is
the number of cycles that occur in 1 second and is measured in Hertz (Hz).
■ Attenuation is the loss of signal strength.
■ Interference is an unwanted signal that combines with and changes the
waveform of the original signal.
■ Latency is the amount of time it takes a signal to travel from its source to its
destination.
■ Bandwidth is a measurement of the ability of network media to carry data;
whereas, frequency is a measurement of the ability of network media to carry
an electronic signal.
■ Baseband is a method of transmitting a single frequency, using the entire
bandwidth of a cable.
■ Broadband is a method of transmitting multiple frequencies or data across a
cable at once.
■ Communication can occur in one of three modes: simplex, half-duplex, and
full-duplex. Simplex communication occurs in one direction only. Half-
duplex communication occurs in both directions, but not at the same time.
Full-duplex communication occurs in both directions at the same time.
■ Electrical energy that travels in only one direction is referred to as direct
current (DC).
■ Electrical energy that constantly reverses its direction of flow is referred to as
alternating current (AC).
■ Electrical resistance is the opposition to the flow of electrical energy.
Resistance is generally used to describe this effect in DC circuits.
■ Impedance is also the opposition to the flow of electrical energy, but it
expresses the amount of resistance encountered in an AC circuit.
■ Reflected loss is the amount of signal reflected from the far end, or receiving
end, of a cable.
■ The electrical phenomenon of a current-carrying conductor inducing current
in a cable of close proximity is called crosstalk.
■ Near-End Crosstalk is a measurement of crosstalk at the near end, or sending
end, of a cable.
■ Alien Crosstalk is crosstalk generated from network cables in close proximity
to each other.
■ The decibel (dB) is an electrical measurement that is used to express the
amount of power or energy gained or lost.
■ Far-End Crosstalk is a measurement of crosstalk at the far end, or receiving
end, of a cable.
■ Equal Level Far-End Crosstalk is a measurement of the negated effects of
cable attenuation caused by crosstalk.
■ Copper conductor wire size is based on its diameter and is expressed as
a size according to the American Wire Gauge AWG. The larger AWG the
number, the smaller the wire size.
■ Three common coaxial cable types that have been used for networking are
RG-6, RG-8 (thicknet), and RG-58 (thinnet).
■ Twisted pair cable is divided into seven categories. The categories are based on
the physical design and capabilities of the cable such as the maximum frequency
rating, the data rate that the cable is capable of, and number of twists per foot.
■ The IEEE 802.3 standard describes the characteristics of various Ethernet
technologies such as 10 Mbps, Fast Ethernet, Gigabit Ethernet, and 10 Gigabit
Ethernet.
■ An Auto-MDIX compliant device automatically reassigns the pin functions
so that a crossover cable is not required for communication.
■ Power over Ethernet (PoE) is a way of powering devices that consume small
amounts of electrical energy, approximately 13 watts at 48 volts, over network
cable.
■ Wiring faults include shorts, opens, reversed pairs, crossed pairs, and split pairs.
Review Questions
Answer the following questions on a separate sheet of paper. Please do not write in this book.
1. _____ signals are sent through copper core cable as pulsating electrical energy.
2. Pulsating light waves are commonly sent through _____ cable.
3. Wireless technology commonly transmits _____ waves, _____ waves, and
_____ through the atmosphere.
4. What are the two types of electrical signals?
5. Time affects the degree of the slope in a(n) _____ signal.
6. Time affects the duration of the voltage level in a(n) _____ signal.
7. How often an analog or digital cycle repeats in one second is called _____.
8. Frequency is measured in _____ and is represented by the abbreviation _____.
9. How many times does an analog cycle repeat in a 2.3-kHz electronic signal?
10. How many times does a digital cycle repeat in a 10-MHz electronic signal?
11. What is attenuation?
12. Noise and crosstalk are types of _____.
13. What is AXT?
14. What is latency?
15. A method of transmitting data in the form of a digital signal, using the entire
bandwidth of a cable is called _____.
16. A method of transmitting data in the form of several analog signals at the
same time is called _____.
17. List the three modes in which communication can occur.
18. What is the difference between half-duplex and full-duplex communication?
19. _____ is opposition to current flow in a DC circuit, and _____ is the opposition
to current flow in an AC circuit.
20. The size of a conductor’s diameter is described by what rating?
21. Which conductor is larger, one that has a 22 AWG rating or one that has a
24 AWG rating?
22. RG-58 is also referred to as _____.
23. What type of coaxial cable is recommended by the EIA/TIA 570 residential
communication standard?
24. Which types of coaxial cable are referred to as thicknet?
25. What is the maximum frequency and data rate associated with Category 6a
cable?
26. What Category 6 cable physical attributes provide improved data rates and
higher frequencies when compared with Category 5 cable?
27. What is the difference between Category 6 and Category 6a?
28. List the following characteristics of a 10BaseT network: topology, cable type,
connector type, maximum segment length, minimum cable length, and data rate.
29. What will happen to an electronic signal in a 10BaseT network if it passes
through more than four hubs?
30. What does the acronym Auto-MDIX represent?
31. What is Auto-MDIX?
32. What is another acronym used to identify the RJ-45 connector?
33. What is the purpose of a rollover cable?
34. What does the acronym PoE represent?
35. What types of devices use PoE?
36. What is the maximum voltage delivered by PoE?
37. What is the term used for a circuit path that is shorter than its intended path?
38. What is the term used for an incomplete circuit path?
39. What is the term used to describe a wire that comes in contact with a metal
enclosure that is touching the earth?
40. Name three possible cable problems that might result from improperly
wiring twisted cable pairs.
Answer the following questions on a separate sheet of paper. Please do not write in this book.
1. _____ signals are sent through copper core cable as pulsating electrical energy.
2. Pulsating light waves are commonly sent through _____ cable.
3. Wireless technology commonly transmits _____ waves, _____ waves, and
_____ through the atmosphere.
4. What are the two types of electrical signals?
5. Time affects the degree of the slope in a(n) _____ signal.
6. Time affects the duration of the voltage level in a(n) _____ signal.
7. How often an analog or digital cycle repeats in one second is called _____.
8. Frequency is measured in _____ and is represented by the abbreviation _____.
9. How many times does an analog cycle repeat in a 2.3-kHz electronic signal?
10. How many times does a digital cycle repeat in a 10-MHz electronic signal?
11. What is attenuation?
12. Noise and crosstalk are types of _____.
13. What is AXT?
14. What is latency?
15. A method of transmitting data in the form of a digital signal, using the entire
bandwidth of a cable is called _____.
16. A method of transmitting data in the form of several analog signals at the
same time is called _____.
17. List the three modes in which communication can occur.
18. What is the difference between half-duplex and full-duplex communication?
19. _____ is opposition to current flow in a DC circuit, and _____ is the opposition
to current flow in an AC circuit.
20. The size of a conductor’s diameter is described by what rating?
21. Which conductor is larger, one that has a 22 AWG rating or one that has a
24 AWG rating?
22. RG-58 is also referred to as _____.
23. What type of coaxial cable is recommended by the EIA/TIA 570 residential
communication standard?
24. Which types of coaxial cable are referred to as thicknet?
25. What is the maximum frequency and data rate associated with Category 6a
cable?
26. What Category 6 cable physical attributes provide improved data rates and
higher frequencies when compared with Category 5 cable?
27. What is the difference between Category 6 and Category 6a?
28. List the following characteristics of a 10BaseT network: topology, cable type,
connector type, maximum segment length, minimum cable length, and data rate.
29. What will happen to an electronic signal in a 10BaseT network if it passes
through more than four hubs?
30. What does the acronym Auto-MDIX represent?
31. What is Auto-MDIX?
32. What is another acronym used to identify the RJ-45 connector?
33. What is the purpose of a rollover cable?
34. What does the acronym PoE represent?
35. What types of devices use PoE?
36. What is the maximum voltage delivered by PoE?
37. What is the term used for a circuit path that is shorter than its intended path?
38. What is the term used for an incomplete circuit path?
39. What is the term used to describe a wire that comes in contact with a metal
enclosure that is touching the earth?
40. Name three possible cable problems that might result from improperly
wiring twisted cable pairs.