using information technology
DESCRIPTION
Using Information Technology. Chapter 7 Telecommunications. Telecommunications Networks & Communications--The “New Story” in Computing. 7.1From the Analog to the Digital Age 7.2The Practical Uses of Communications 7.3Communications Channels: The Conduits of Communications - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: Using Information Technology](https://reader036.vdocument.in/reader036/viewer/2022062422/56812c28550346895d909daa/html5/thumbnails/1.jpg)
Using Information Technology
Chapter 7Telecommunications
![Page 2: Using Information Technology](https://reader036.vdocument.in/reader036/viewer/2022062422/56812c28550346895d909daa/html5/thumbnails/2.jpg)
Tele
com
munic
ati
ons
2
Telecommunications Networks & Communications--The “New Story” in Computing
7.1From the Analog to the Digital Age
7.2The Practical Uses of Communications
7.3Communications Channels: The Conduits of Communications
7.4Factors Affecting How Data Is Transmitted...
![Page 3: Using Information Technology](https://reader036.vdocument.in/reader036/viewer/2022062422/56812c28550346895d909daa/html5/thumbnails/3.jpg)
Tele
com
munic
ati
ons
3
Networks & Communications--The “New Story” in Computing
7.5Networks
7.6The Future of Communications
7.7Cyberethics: Controversial Material, Privacy, & Intellectual Property
![Page 4: Using Information Technology](https://reader036.vdocument.in/reader036/viewer/2022062422/56812c28550346895d909daa/html5/thumbnails/4.jpg)
Tele
com
munic
ati
ons
4
7.1 From the Analog to the Digital Age
Analog - continuous and varying in strength and/or quality
Digital - communications signals or information represented in a two-stat (binary) way
![Page 5: Using Information Technology](https://reader036.vdocument.in/reader036/viewer/2022062422/56812c28550346895d909daa/html5/thumbnails/5.jpg)
Tele
com
munic
ati
ons
5
Purpose of the Modem: Converting Digital Signals to Analog Signals & Back
Sending modem - modulates digital signals into analog signals for transmission over phone lines
Receiving modem - demodulates the analog signals back into digital signals
Modem - short for modulate/demodulate
![Page 6: Using Information Technology](https://reader036.vdocument.in/reader036/viewer/2022062422/56812c28550346895d909daa/html5/thumbnails/6.jpg)
Tele
com
munic
ati
ons
6
7.2 The Practical Uses of CommunicationsVideoconferencing & VideophonesVideoconferencing - the use of television video and sound technology as well as computers to enable people in different locations to see, hear, and talk with one another
![Page 7: Using Information Technology](https://reader036.vdocument.in/reader036/viewer/2022062422/56812c28550346895d909daa/html5/thumbnails/7.jpg)
Tele
com
munic
ati
ons
7
Workgroup Computing & Groupware
Workgroup computing - teams of co-workers use networks of microcomputers to share information and to cooperate on projects
Made possible by networks, microcomputers, & groupware
![Page 8: Using Information Technology](https://reader036.vdocument.in/reader036/viewer/2022062422/56812c28550346895d909daa/html5/thumbnails/8.jpg)
Tele
com
munic
ati
ons
8
Telecommuting
Telecommuting - working at home while in telecommunication with the office
![Page 9: Using Information Technology](https://reader036.vdocument.in/reader036/viewer/2022062422/56812c28550346895d909daa/html5/thumbnails/9.jpg)
Tele
com
munic
ati
ons
9
Virtual Offices
Virtual office - an often nonpermanent and mobile office run with computer and communications technology
![Page 10: Using Information Technology](https://reader036.vdocument.in/reader036/viewer/2022062422/56812c28550346895d909daa/html5/thumbnails/10.jpg)
Tele
com
munic
ati
ons
10
Smart Television
Digital television (DTV) - uses a digital signal, or series of 0s and 1s
High-definition television (HDTV) - high-resolution type of DTV
Standard-definition television (SDTV) - allows broadcasters to transmit more information within the HDTV bandwidth
![Page 11: Using Information Technology](https://reader036.vdocument.in/reader036/viewer/2022062422/56812c28550346895d909daa/html5/thumbnails/11.jpg)
Tele
com
munic
ati
ons
11
Other Practical Uses of Communications
Home network - LAN which allows all the personal computers under the same roof to share peripherals and a single modem and Internet service
Information/internet appliance - a device merging computing capabilities with communications gadgets
TV set-top boxesInternet phonesPDAs
![Page 12: Using Information Technology](https://reader036.vdocument.in/reader036/viewer/2022062422/56812c28550346895d909daa/html5/thumbnails/12.jpg)
Tele
com
munic
ati
ons
12
7.3 Communications Channels: The Conduits of Communications
Communications channel - the path (physical medium) over which information travels in a telecommunications system from its source to its destination
![Page 13: Using Information Technology](https://reader036.vdocument.in/reader036/viewer/2022062422/56812c28550346895d909daa/html5/thumbnails/13.jpg)
Tele
com
munic
ati
ons
13
The Electromagnetic Spectrum, the Radio Spectrum, & Bandwidth
Radio frequency spectrum
![Page 14: Using Information Technology](https://reader036.vdocument.in/reader036/viewer/2022062422/56812c28550346895d909daa/html5/thumbnails/14.jpg)
Tele
com
munic
ati
ons
14
Wired Communications Channels
Twisted-pair wire - two strands of insulated copper wire, twisted around each other
![Page 15: Using Information Technology](https://reader036.vdocument.in/reader036/viewer/2022062422/56812c28550346895d909daa/html5/thumbnails/15.jpg)
Tele
com
munic
ati
ons
15
Wired Communications Channels
Coaxial cable - insulated copper wire wrapped in a solid or braided metal shield, then in an external cover
![Page 16: Using Information Technology](https://reader036.vdocument.in/reader036/viewer/2022062422/56812c28550346895d909daa/html5/thumbnails/16.jpg)
Tele
com
munic
ati
ons
16
Wired Communications Channels
Fiber-optic cable - dozens or hundreds of thin strands of glass or plastic that transmit pulsating beams of light rather than electricity
![Page 17: Using Information Technology](https://reader036.vdocument.in/reader036/viewer/2022062422/56812c28550346895d909daa/html5/thumbnails/17.jpg)
Tele
com
munic
ati
ons
17
Wireless Communications Channels
Infrared transmission - the transmission of data signals using infrared-light waves
![Page 18: Using Information Technology](https://reader036.vdocument.in/reader036/viewer/2022062422/56812c28550346895d909daa/html5/thumbnails/18.jpg)
Tele
com
munic
ati
ons
18
Wireless Communications Channels
Broadcast radio - a wireless transmission medium that sends data over long distances--between regions, states, or countries
Microwave radio - transmits voice & data through the atmosphere as super-high-frequency radio waves called microwaves
![Page 19: Using Information Technology](https://reader036.vdocument.in/reader036/viewer/2022062422/56812c28550346895d909daa/html5/thumbnails/19.jpg)
Tele
com
munic
ati
ons
19
Wireless Communications Channels
Communications satellites - microwave relay stations in orbit around the earth
![Page 20: Using Information Technology](https://reader036.vdocument.in/reader036/viewer/2022062422/56812c28550346895d909daa/html5/thumbnails/20.jpg)
Tele
com
munic
ati
ons
20
Long-Distance Wireless Communications
Global Positioning System (GPS) - a series of earth-orbiting satellites continuously transmitting timed radio signals that can be used to identify earth locations
![Page 21: Using Information Technology](https://reader036.vdocument.in/reader036/viewer/2022062422/56812c28550346895d909daa/html5/thumbnails/21.jpg)
Tele
com
munic
ati
ons
21
Long-Distance Wireless Communications
Pagers - simple radio receivers that receive data (but not voice messages) sent from a special radio transmitter
One-way pagersTwo-way pagers (enhanced paging)
Acknowledgments from recipient to senderEmail composition & sendingMessages to other pagers
![Page 22: Using Information Technology](https://reader036.vdocument.in/reader036/viewer/2022062422/56812c28550346895d909daa/html5/thumbnails/22.jpg)
Tele
com
munic
ati
ons
22
Long-Distance Wireless Communications
Analog cellular phones - designed primarily for communicating by voice through a system of ground-area cells
Cell - hexagonal shape, usually 8 miles or less in diameter, & served by a transmitter-receiving tower
![Page 23: Using Information Technology](https://reader036.vdocument.in/reader036/viewer/2022062422/56812c28550346895d909daa/html5/thumbnails/23.jpg)
Tele
com
munic
ati
ons
23
Long-Distance Wireless Communications
Digital wireless services (2G) - support digital cellphones & PDAs, using a network of cell towers to send voice communications & data over the airwaves in digital form
Broadband wireless digital services (3G) - “always on” technology which can quickly transmit video, still pictures, and music, along with offering better ways to tape into websites than today’s 2G wireless systems
2.5G - compromise between 2G and 3G, which is an “always on” version of 2G technology
![Page 24: Using Information Technology](https://reader036.vdocument.in/reader036/viewer/2022062422/56812c28550346895d909daa/html5/thumbnails/24.jpg)
Tele
com
munic
ati
ons
24
Short-Range Wireless Communications
Bluetooth - a short-range wireless digital standard aimed at linking cellphones, PDAs, computers, & peripherals up to distances of 30 feet
WiFI - a short-range wireless digital standard aimed at helping machines inside offices to communicate at high speeds and share Internet connections at distances up to 300 feet
HomeRF - a separate, incompatible standard designed to network up to 10 PCs & peripherals as far as 150 feet apart
![Page 25: Using Information Technology](https://reader036.vdocument.in/reader036/viewer/2022062422/56812c28550346895d909daa/html5/thumbnails/25.jpg)
Tele
com
munic
ati
ons
25
Compression & Decompression: Putting More Data in Less Space
Compression - a method of removing repetitive elements from a file so that the file requires less storage space and therefore less time to transmit
Lossless vs. lossy
Standards
JPEGMPEG
![Page 26: Using Information Technology](https://reader036.vdocument.in/reader036/viewer/2022062422/56812c28550346895d909daa/html5/thumbnails/26.jpg)
Tele
com
munic
ati
ons
26
7.4 Factors Affecting How Data Is Transmitted
Transmission rate - a function of two variables:
Frequency - the cycles of waves per second
Bandwidth - the range between the highest & lowest frequencies
Higher frequency => greater transmission rateLarger bandwidth => greater transmission rate
![Page 27: Using Information Technology](https://reader036.vdocument.in/reader036/viewer/2022062422/56812c28550346895d909daa/html5/thumbnails/27.jpg)
Tele
com
munic
ati
ons
27
Factors Affecting How Data Is Transmitted
Line configurations
Point-to-point line - directly connects the sending & receiving devices
Multipoint line - a single line that interconnects several communications devices to one computer
![Page 28: Using Information Technology](https://reader036.vdocument.in/reader036/viewer/2022062422/56812c28550346895d909daa/html5/thumbnails/28.jpg)
Tele
com
munic
ati
ons
28
Factors Affecting How Data Is Transmitted
Serial vs. parallel transmission
Serial data transmission - bits are transmitted sequentially, one after the other
![Page 29: Using Information Technology](https://reader036.vdocument.in/reader036/viewer/2022062422/56812c28550346895d909daa/html5/thumbnails/29.jpg)
Tele
com
munic
ati
ons
29
Factors Affecting How Data Is Transmitted
Serial vs. parallel transmission
Parallel data transmission - bits are transmitted through separate lines simultaneously
![Page 30: Using Information Technology](https://reader036.vdocument.in/reader036/viewer/2022062422/56812c28550346895d909daa/html5/thumbnails/30.jpg)
Tele
com
munic
ati
ons
30
Factors Affecting How Data Is Transmitted
Direction of transmission: simplex, half-duplex, & full-duplex
Simplex transmission - data can travel in only one direction
![Page 31: Using Information Technology](https://reader036.vdocument.in/reader036/viewer/2022062422/56812c28550346895d909daa/html5/thumbnails/31.jpg)
Tele
com
munic
ati
ons
31
Factors Affecting How Data Is Transmitted
Direction of transmission: simplex, half-duplex, & full-duplex
Half-duplex transmission - data travels in both directions but only in one direction at a time
![Page 32: Using Information Technology](https://reader036.vdocument.in/reader036/viewer/2022062422/56812c28550346895d909daa/html5/thumbnails/32.jpg)
Tele
com
munic
ati
ons
32
Factors Affecting How Data Is Transmitted
Direction of transmission: simplex, half-duplex, & full-duplex
Full-duplex transmission - data is transmitted back and forth at the same time
![Page 33: Using Information Technology](https://reader036.vdocument.in/reader036/viewer/2022062422/56812c28550346895d909daa/html5/thumbnails/33.jpg)
Tele
com
munic
ati
ons
33
Factors Affecting How Data Is Transmitted
Asynchronous transmission - data is sent one byte at a time, with each string of bits making up the byte bracketed with special control bits
Transmission mode: asynchronous vs. synchronous
![Page 34: Using Information Technology](https://reader036.vdocument.in/reader036/viewer/2022062422/56812c28550346895d909daa/html5/thumbnails/34.jpg)
Tele
com
munic
ati
ons
34
Factors Affecting How Data Is Transmitted
Synchronous transmission - data is sent in blocks, with start and stop bit patterns (synch bytes) at the beginning and end of the blocks
Transmission mode: asynchronous vs. synchronous
![Page 35: Using Information Technology](https://reader036.vdocument.in/reader036/viewer/2022062422/56812c28550346895d909daa/html5/thumbnails/35.jpg)
Tele
com
munic
ati
ons
35
Factors Affecting How Data Is Transmitted
Circuit switching - transmitter has full use of the circuit until all the data has been transmitted and the circuit is terminated
Packet switching - electronic messages are divided into packets for transmission over a wide area network to their destination through the most expedient route
![Page 36: Using Information Technology](https://reader036.vdocument.in/reader036/viewer/2022062422/56812c28550346895d909daa/html5/thumbnails/36.jpg)
Tele
com
munic
ati
ons
36
Factors Affecting How Data Is Transmitted
MultiplexersConcentratorsFront-end
processors
Multiplexing - transmission of multiple signals over a single communications channel
![Page 37: Using Information Technology](https://reader036.vdocument.in/reader036/viewer/2022062422/56812c28550346895d909daa/html5/thumbnails/37.jpg)
Tele
com
munic
ati
ons
37
Factors Affecting How Data Is Transmitted
Protocol - a set of conventions governing the exchange of data between hardware and/or software components in a communications network
![Page 38: Using Information Technology](https://reader036.vdocument.in/reader036/viewer/2022062422/56812c28550346895d909daa/html5/thumbnails/38.jpg)
Tele
com
munic
ati
ons
38
7.5 Networks
Benefits of networks:
Sharing of peripheral devices
Sharing of programs and data
Better communications
Security of information
Access to databases
![Page 39: Using Information Technology](https://reader036.vdocument.in/reader036/viewer/2022062422/56812c28550346895d909daa/html5/thumbnails/39.jpg)
Tele
com
munic
ati
ons
39
Types of Networks
Wide area network (WAN) - a communications network that covers a wide geographical area, such as a country or the world
![Page 40: Using Information Technology](https://reader036.vdocument.in/reader036/viewer/2022062422/56812c28550346895d909daa/html5/thumbnails/40.jpg)
Tele
com
munic
ati
ons
40
Types of Networks
Metropolitan area network (MAN) - a communications network covering a city or a suburb
Local area network (LAN) - connects computers and devices in a limited geographical area
![Page 41: Using Information Technology](https://reader036.vdocument.in/reader036/viewer/2022062422/56812c28550346895d909daa/html5/thumbnails/41.jpg)
Tele
com
munic
ati
ons
41
Types of Networks
Host computer - a mainframe or midsize central computer that controls the network
Node - any device that is attached to a network
Backbone - a high-speed network that connects LANs and MANs to the Internet
![Page 42: Using Information Technology](https://reader036.vdocument.in/reader036/viewer/2022062422/56812c28550346895d909daa/html5/thumbnails/42.jpg)
Tele
com
munic
ati
ons
42
Types of LANs
Client/server LAN:
Clients - microcomputers that request data; and
Server - a powerful microcomputer that manages shared devices
![Page 43: Using Information Technology](https://reader036.vdocument.in/reader036/viewer/2022062422/56812c28550346895d909daa/html5/thumbnails/43.jpg)
Tele
com
munic
ati
ons
43
Types of LANs
Peer-to-peer LAN - all microcomputers on the network communicate directly with one another without relying on a server
![Page 44: Using Information Technology](https://reader036.vdocument.in/reader036/viewer/2022062422/56812c28550346895d909daa/html5/thumbnails/44.jpg)
Tele
com
munic
ati
ons
44
Components of LANs
Connection or cabling system
Microcomputers with network interface cards
Network OS
Other shared devices
Routers, bridges, and gateways
![Page 45: Using Information Technology](https://reader036.vdocument.in/reader036/viewer/2022062422/56812c28550346895d909daa/html5/thumbnails/45.jpg)
Tele
com
munic
ati
ons
45
Topology of LANs
Star network - one in which all microcomputers and other communications devices are connected to a central server
![Page 46: Using Information Technology](https://reader036.vdocument.in/reader036/viewer/2022062422/56812c28550346895d909daa/html5/thumbnails/46.jpg)
Tele
com
munic
ati
ons
46
Topology of LANs
Ring network - one in which all microcomputers and other communications devices are connected in a continuous loop
![Page 47: Using Information Technology](https://reader036.vdocument.in/reader036/viewer/2022062422/56812c28550346895d909daa/html5/thumbnails/47.jpg)
Tele
com
munic
ati
ons
47
Topology of LANs
Bus network - one in which all communications devices are connected to a common channel
![Page 48: Using Information Technology](https://reader036.vdocument.in/reader036/viewer/2022062422/56812c28550346895d909daa/html5/thumbnails/48.jpg)
Tele
com
munic
ati
ons
48
Intranets, Extranets, & Firewalls
Intranet - an organization’s internal private network that uses the infrastructure and standards of the Internet and the WWW
Extranets - private intranets that connect not only internal personnel but also selected suppliers and other strategic parties
Firewalls - a system of hardware and software that blocks unauthorized users inside and outside the organization from entering the intranet
![Page 49: Using Information Technology](https://reader036.vdocument.in/reader036/viewer/2022062422/56812c28550346895d909daa/html5/thumbnails/49.jpg)
Tele
com
munic
ati
ons
49
7.6 The Future of Communications
Satellite-based systems
Beyond 3G to 4G
Photonics: optical technologies at warp speed
![Page 50: Using Information Technology](https://reader036.vdocument.in/reader036/viewer/2022062422/56812c28550346895d909daa/html5/thumbnails/50.jpg)
Tele
com
munic
ati
ons
50
7.7 Cyberethics
Controversial material & censorship:
Blocking software
Browsers with ratings
The V-Chip
![Page 51: Using Information Technology](https://reader036.vdocument.in/reader036/viewer/2022062422/56812c28550346895d909daa/html5/thumbnails/51.jpg)
Tele
com
munic
ati
ons
51
Cyberethics
Privacy - the right of people not to reveal information about themselves
Cookie - a file that the web server stores on your hard-disk drive when you visit a website