Part I---Lesson

Networks

Types of Networks

• Local Area Network (LAN) is a collection of computers and devices like printers that are connected by wire over a relatively short distance.

• Wide Area Network (WAN) allow computers to be connected over vast distances using microwaves, satellites and telephone lines.

Advantages of Networks

• Improved data security- data is centrally stored.

• Improved data integrity- data can be regularly backed-up and stored.

• Improved data consistency- easier update

• educed software costs- shared software

• Reduced hardware costs- shared hardware.

• Improved organizational communications

Disadvantages of Networks

• Initial Expense- costly set in terms of adapter cards, cabling, training, setup, etc.

• Ongoing expense- highly-skilled person to continually support users on the network and maintain system,

• Downtown disruptions- everyone’s work can be disrupted if the system goes down.

• Hacker interception- network servers, if not properly secured, make prime targets for hackers.

Modem

• A modem is a peripheral device that allows the transmission of digital information from a computer across telephone lines.

• Telephone lines normally transmit voice data in an analog format.

• The modem converts the outgoing signal from digital to analog, and the incoming signal from analog to digital.

Telephone Network

• Once an outgoing signal has been transformed to analog by the modem, it can be transmitted across a public switched telephone network (PSTN).

• The transfer rate of the data is known as bits per second (Bps). Modems most commonly transfer data at the rate of 56,000 (56K) Bps.

Electronic Mail

• The growth of communications, wide area networks, and local area networks has made it possible to send and receive electronic messages.

• These electronic messages are known as e-mail.

The Internet

• The Internet is a very large network of linked computers that can communicate with each other.

Use of the Internet

• When you log onto the Internet using Netscape or Microsoft's Internet Explorer or some other browser, you are viewing documents on the World Wide Web.

• The development and sophistication of search engines has made it possible for the Internet to provide product information, online courses, and access to all sorts of information.

World Wide Web

• The World Wide Web (www) is a computer network consisting of a collection of internet sites that offer text and graphics and sound and animation resources through the hypertext transfer protocol (http).

Part II—Worksheet

1. _____________ ____________ _______________ is a collection of computers in one geographical location connected via cables.
2. _____________ ____________ _______________ is a collection of computers in diverse locations connected via specialized communications equipment or by a telephone network.
3. A peripheral device that allows the transmission of digital information from a computer across telephone lines is called a___________________________.
4. Telephone lines normally transmit voice data in an ________________ format.
5. The modem converts the outgoing signal from digital to __________________, and the incoming signal from analog to _______________.
6. Once an outgoing signal has been transformed to analog by the modem, it can be transmitted across _________________ ____________________ ___________________ ______________________.
7. The transfer rate of the data is known _____________ ____________ _________________.
8. A very large network of linked computers that can communicate with each other is called the _______________________.
9. The growth of communications, wide area networks, and local area networks has made it possible to send and receive electronic messages, these electronic messages are known _____________________.
10. The ______________ _____________ ____________ is a computer network consisting of a collection of internet sites that offer text and graphics and sound and animation resources through the hypertext transfer protocol (http).