1. Internet & Communications Technology
SECTION 4
APPLICATIONS & IMPLICATIONS OF INFORMATION TECHNOLOGY & COMMUNICATIONS TECHNOLOGY
Internet & Communications Technology

2. Internet & Communications Technology
On completing Section 4, you should be able
to:
Use terms associated with data communications & networks
Distinguish among Internet, Intranet & Extranet
Explain concepts associated with the internet
Describe measures to secure data & maintain data integrity

3. Internet & Communications Technology
Today’s class will cover the following objectives:
Use terms associated with data communications & networks
Distinguish among Internet, Intranet & Extranet

4. Internet & Communications Technology
Definitions:
Data Communication:
Transmission of data from one location to another to enable interaction between locations.
Network:
Group of computers & peripheral devices that are connected to each other by cables or wireless electronics.
Bandwidth:
Volume of data that can be transmitted through the channel each second

5. Internet & Communications Technology
Definitions: (continued)
Modem (Modulator/Demodulator)
Device that converts digital signals into analog signals and vice versa. It is measured in bits per second (bps).
Upload
Process by which the host computer sends a file to a remote computer via communication channels
Download
Process by which a host computer obtains a file from a remote computer via communication channels.

6. Internet & Communications Technology
Definitions: (continued)
Point-to-Point transmission
Process by which data is sent from one location to another.
Broadcast transmission
Process by which data is transmitted in such a way that any person with the proper equipment can receive it. With this transmission, it is difficult to control who receives the data.
Hotspot
Any location where network access (usually Internet access) is publicly available.

7. Internet & Communications Technology
Definitions: (continued)
Protocol
Set of rules and procedures controlling the transmission and receipt of data so that different devices can communicate with each other
File Server
Computer with large storage capacity that is used to store and manage files which are used by other computers on the network.

8. Internet & Communications Technology
Data Communication
There are 3 categories of data communication channels:
Narrowband:
Data is transmitted at a slow speed (just over 10 characters/second), e.g., telegraphed transmission
Voiceband:
Data is transmitted at rates of up to 8000 characters/second via telephone lines.
Broadband:
Data is transmitted very quickly (hundreds of thousands of characters/second) via the use of fibre-optic cables, microwave and satellite transmissions.

9. Internet & Communications Technology
Types of Communication Modes
Simplex:
Data is transmitted in only one direction
Half Duplex:
Data can be transmitted in both directions, but not at the same time.
Duplex or Full-Duplex:
Communication is allowed in both directions and it can occur simultaneously.
What are examples of each type?

10. Internet & Communications Technology
Networks
There are 3 types of networks that we will look at:
Local Area Network (LAN)
Metropolitan Area Network (MAN)
Wide Area Network (WAN)

11. Internet & Communications Technology
Local Area Networks (LANs)
Two or more computers connected to each other within the same geographical area (not necessarily in the same building – home, office, small group of buildings (school, airport))
Used by small and medium-sized businesses.
Connected using twisted pair cables or coaxial cables.
Wireless technology is being used within LANs. Radio & microwave signals are used to transmit data instead of cables

12. Internet & Communications Technology
Wide Area Networks (WANs)
Covers a wide geographical area.
Not linked by coaxial or twisted pair cables
Communication is possible via the use of fibre-optic cables and telephone lines, satellite and microwave technology.
Large volumes of data can be transmitted across a WAN

13. Internet & Communications Technology
Metropolitan Area Networks (MANs)
Large network spanning a city area or campus
Usually interconnects a number of LANs
The geographic scope falls in between a LAN and a WAN – ranges from several blocks of buildings to entire cities
Depends on communication channels of moderate to high data rates

14. Internet & Communications Technology
Types of Network Layouts
There are 3 main types of layout of computer networks:
Star Network
Each computer is connected to a central hub. It has its own connection to the network
A break in a cable will not affect the other computers
Most expensive to install, but the quickest.

15. Internet & Communications Technology
Types of Network Layouts
Bus Network
All computers are in a line.
Cheap and reliable
If the cable breaks, the network is split.
Slower than star networks

16. Internet & Communications Technology
Types of Network Layouts
Ring Network
The last computer is connected to the first computer forming a ring or loop.
Slower than star networks

17. Internet & Communications Technology
Transmission Media
From the previous section, we noted that there are several types of media used to transmit data across networks
There are two major categories:
Cabled/Wired Media:
Twisted Pair, Coaxial, Fiber-Optic
Wireless Media
Satellite, Microwave, Infra-red

18. Internet & Communications Technology
Cabled/Wired Media
Twisted Pair:
Type of wiring where two conductors are twisted together to cancel out any electromagnetic interference from external sources.
Cheap to acquire
Relatively slow; transmits small volumes of data

19. Internet & Communications Technology
Cabled/Wired Media (continued)
Coaxial:
electrical cable surrounded by conductive and insulating layers
Faster, but more expensive than twisted pair cables.
Used when voice and video transmissions are needed
Also used when large amounts of data needs to be transmitted.

20. Internet & Communications Technology
Cabled/Wired Media (continued)
Fiber-Optic:
Thin cables through which light passes.
Data is transmitted via the light
Allows fast and accurate transmission of large volumes of data
Popular in telecommunication industry

21. Internet & Communications Technology
Wireless Media
Satellite:
A station on the ground sends and receives signals from the satellite
Bandwidth is traditionally approximately 100 GHz
Microwave:
Used in broadcasting and telecommunication transmissions
Short wavelength
More bandwidth in microwave spectrum

22. Internet & Communications Technology
Wireless Media (continued)
Infra-red:
Used in short range communication among computer peripherals
Data is transmitted via an infrared beam which is switched on and off to encode data.

23. Internet & Communications Technology
Wireless Network Technology
The popular wireless technologies that we use today are:
Bluetooth
Open wireless protocol used to exchange data over a short distance
Uses a radio communication system, hence they don’t have to be in line of sight of each other to transmit data.
Wi-Fi
Used with certified products that belong to a class of wireless LAN devices
Used as a synonym for IEEE
Installed in many PCs, video game consoles, smartphones, printers

24. Internet & Communications Technology
Largest computer network system in the world.
Consists of smaller networks connected together by a global public network.
Often called the information superhighway or cyberspace
Intranet:
Private network that belongs to an organization, and is designed to be accessible only by the organization’s members, employees and authorized persons.

25. Internet & Communications Technology
Extranet:
When part of the intranet is made accessible to customers, partners, suppliers, or others outside the company.