Deck 13: Transmission Medium

Question 1

Which of the following is true?

A) several different medium types may often be used to carry a single piece of information across a network
B) our current telecommunications network uses copper wire, fiber optic glass strands, and air waves to transport information
C) every medium has an information "carrying capacity"
D) all of the above

Answer 1

all of the above

Question 2

A(n) ________ may be a braided mesh of wires or a thin metal jacket resembling aluminum foil that surrounds the conductors, and its purpose is to insulate conductors from outside electrical forces.

Answer 2

shield

Question 3

Which of the following is not a consideration when determining which type of copper cable to use for a project?

A) Will the cable be placed inside or outside?
B) How far does the signal have to travel?
C) Are there strong electromagnetic influences in the area?
D) Will the copper wire be used to carry voice frequencies only?

Answer 3

Will the copper wire be used to carry voice frequencies only?

Question 4

In communications, 14, 18, 22, 24, and 26 are all common cable gauges used in networks.

Question 5

A medium capable of carrying electrical signals is called a(n) ________.

Question 6

Electrical conductors used in communications are made of ________.

Question 7

What is the purpose of crossing the tip and ring wires over each other to form a twisted pair?

A) to produce a canceling effect of the signals and thus eliminate cross talk
B) to block electromagnetic interference from outside influences such as fluorescent lights
C) both a and b are true
D) neither a nor b is true

Question 8

A feeder cable may have as many as 6,000 wire pairs.

Question 9

Two bare conductors touch and complete a circuit, causing an outage or ________.

Question 10

The purpose of the metallic shield on coaxial cable includes all of the following except:

A) act as an electrical return path
B) carry the signal
C) offer protection against interference such as electromagnetic forces and cross talk
D) limit the radiation or bleeding of the signal out of the cable

Question 11

Coaxial cable has a center copper conductor of a specific gauge surrounded by a(n) ________ insulation.

Question 12

The most common use of coaxial cable is to carry a cable TV signal from a cable provider to a subscriber's home.

Question 13

An eight-wire conductor that is used to terminate four-wire or two-pair T1 circuits is the:

A) RJ-11
B) RJ-21
C) RJ-45
D) RJ-48

Question 14

________ connectors are defined as either male or female and are advantageous because of the reduced time it takes to terminate wires compared with punch-down or wrap terminations.

Question 15

The RS-232 is used to transmit higher speed signals than the V.35.

Question 16

The benefit of using the V.35 connector over the RS-232 is that the V.35 provides:

A) better conduction for high-speed signals
B) less signal loss
C) lower signal-to-noise ratios
D) fewer errors
E) all of the above

Question 17

It is important to remember that some sort of ________ jack or block is needed to complete a copper circuit and that many jacks and blocks are also used to provide a cross connect point and test point.

Question 18

________ is the outer glass layer of fiber-optic cable that surrounds the core and keeps light in the core.

Question 19

Single mode fiber does not suffer from modal dispersion because it has a very small ________.

Question 20

Which of the following is an index used to describe how the medium reflects light?

A) dispersion
B) graded
C) refractive
D) step

Question 21

Unlike chromatic dispersion, PMD (polarization mode dispersion) is caused by the structural change of the geometric shape of the fiber, and its value is determined only after the fiber is installed.

Question 22

Loss in fiber-optic strands is called ________.

Question 23

The ________ is the source most often used for transmitting information across a network using light.

Question 24

Lasers have less power than LEDs and are therefore used for shorter-haul applications.

Question 25

An optical amplifier boosts the incoming signal, then transmits it back out onto the fiber pipe.

Question 26

Compared to a regenerator, the optical amplifier requires:

A) less space
B) less power
C) less maintenance
D) all of the above

Question 27

The disadvantage in using optical amplification rather than regeneration is that it is much more expensive.

Question 28

The disadvantage in using optical amplification rather than regeneration is that it is much more expensive.

Question 29

The mechanical splice is usually used in outside telephone plants.

Question 30

Which of the following would not require the use of satellite technology?

A) a facsimile being sent from the United States to Great Britain
B) a telephone conversation between Jan and her mother, who live on opposite sides of Detroit
C) live United States television coverage of a newsworthy event in the Middle East
D) none of the above requires satellite technology

Question 31

A(n) ________ is a copper conductor that is the transmission medium used in microwave technology to connect the radio oscillator to the antenna.

Question 32

It is speculated that microwave technology will eventually become obsolete due to the continuing explosion of fiber-optic systems.

Question 33

The frequency spectrum available for satellite links is relatively inexpensive, but it is limited.

Question 34

________ occurs in satellite transmission when a signal reflects back on itself and causes the sender to hear himself or herself speak, but improved technology has improved cancellation methods, reducing it significantly.

Question 35

The three bands on the frequency spectrum available to communications providers for satellite links include all of the following except the:

A) C band
B) Ca band
C) Ku band
D) Ka band

Question 36

Very small aperture terminals (VSATs) are small satellite ________.