Introduction to ICT and Programming Lecture # 3 : Internet & World Wide Web.
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Introduction to ICT and Programming
Lecture # 3 : Internet & World Wide Web
The World of The Internet
The Internet & the World Wide Web
2.1 Choosing Your Internet Access Device & Physical Connection: The Quest for Broadband
2.2 Choosing Your Internet Service Provider (ISP)
2.3 Sending & Receiving E-Mail
2.4 The World Wide Web
2.5 The Online Gold Mine: More Internet Resources, Your Personal Cyberspace, E-Commerce, & the E-conomy
Exploring Cyberspace
2.1 Choosing Your Internet Access
This section discusses the different technologies used to connect individuals to the internet including: – 1. Access device: a personal computer
with a modem – 2. Physical connection: a telephone
line
Device & Physical Connection
Physical connection
The wired or wireless means of connecting to the Internet.
Data Transmission Rates
Data is transmitted in bits per second. – bps stands for bits per second. A bit is the smallest unit
of information used by computers. A computer with an older modem might have a speed of 28,800 bps per second.
– Kbps stands for kilobits per second. This is the most frequently used measure.
– Mbps stands for megabits per second
– Gbps stands for gigabits per second
Bandwidth
- an expression of how much data can be sent through a communications channel in a given amount of time
Broadband - very high speed connection
Download & Upload
Download - to transmit data from a remote computer to a local computer
Upload - to transmit data from a local computer to a remote computer
Telephone (Dial-Up) Modem:
Modem - device that sends and receives data over telephone lines to and from computers
Most modems today have a maximum speed of 56 Kbps.
Low Speed but Inexpensive & Widely Available
Using a modem and phone line to establish a connection to the Internet is called making a dial-up connection.
High-Speed Phone Lines:
Integrated Services Digital network (ISDN) - hardware and software that allows voice, video, and data to be communicated over traditional copper-wire telephone lines. Speeds up to 128 kbps.
Digital Subscriber Line (DSL) - also uses regular phone lines but much faster than ISDN. Download speeds 1.5 – 8.4 Mbps
T1 - a traditional trunk line that carries 24 normal telephone circuits and has a transmission rate of 1.5 Mbps
More Expensive but Available in Most Cities
High-Speed Lines
Cable : Close Competitor to DSLSpeeds up to 10 Mbps
Fiber Optics: Can support speeds up to 2 Gbps
Wireless Systems: Satellite & Other
Satellite: With a pizza-size satellite dish on your roof, you can receive data at the rate of 400 Kbps from a communications satellite, a space station that transmits radio waves called microwaves from earth-based stations.
Other wireless connections: In urban areas, some businesses are using radio waves transmitted between towers that handle cellular phone calls, which can send data at up to 155 Mbps.
Through-the-Air Connections
Thank you
Thank you
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