Chapter 6-Fundamentals

Question 1

Telecommunications

Answer 1

The electronic transmission of signals for communications, by such means as telephone, radio, and television
Telecommunications impacts businesses greatly because it lessens the barriers of time and distance

Question 2

Sending unit

Answer 2

A sending unit such as a person, a computer system, a terminal, or another device, sends the message signal to a telecommunications device

Question 3

Telecommunications medium

Answer 3

A telecommunications medium is any material substance that carries an electronic signal to support communications between a sending and receiving device

Question 4

Synchronous communication

Answer 4

the receiver gets the message almost instantaneously, when it is sent. Examples are a phone call, and instant messaging services such as MSN

Question 5

Asynchronous communication

Answer 5

there is a measurable delay between the sending and receiving of the message, sometimes hours or even days. Examples are sending a letter through the post office and e-mail

Question 6

Channel bandwidth

Answer 6

The rate at which data is exchanged, usually measured in bits per second (bps) e.g. Kbps, Mbps, Gbps
The broader the bandwidth, the more info can be exchanged
Broadband communications
Narrowband communications

Question 7

Transmission media

Answer 7

can be divided into two broad categories: guided transmission media, in which communications signals are guided along a solid medium; and wireless, in which the communications signal is broadcast over airwaves as a form of electromagnetic radiation

Question 8

Twisted-­pair wire

Answer 8

contains two or more twisted pairs of wire, usually copper .Proper twisting of the wire keeps the signal from ‘bleeding’ into the next pair and creating electrical interference. Because the twisted­ pair wires are insulated, they can be placed close together and packaged in one group. Hundreds of wire pairs can be grouped into one large wire cable.

Question 9

Coaxial cable

Answer 9

falls in the middle of the guided transmission media in terms of cost and performance. The cable itself is more expensive than twisted­ pair wire but less so than fibre­ optic cable. Coaxial cable offers cleaner and crisper data transmission (less noise) than twisted­ pair wire. It also offers a higher data transmission rate.

Question 10

Fiber ­optic cable

Answer 10

Consisting of many extremely thin strands of glass or plastic bound together in a sheathing (a jacket), transmits signals with light beams . These high­ intensity light beams are generated by lasers and are conducted along the transparent fibers. These fibers have a thin coating, called cladding, which effectively works like a mirror, preventing the light from leaking out of the fiber. The much smaller diameter of fiber ­optic cable makes it ideal when there is not room for bulky copper wires – for example, in crowded conduits, which can be pipes or spaces carrying both electrical and communications wires. Because fiber optic cables are immune to electrical interference, they can transmit signals over longer distances with fewer expensive repeaters to amplify or rebroadcast the data

Question 11

Broadband over power lines

Answer 11

Data transmitted over standard high-voltage power lines
can provide internet service to rural areas
Can be expensive