Introduction 3 - Modems

Introduction...

  3. Modems

Modem is the shorter form for MOdulator/DEModulator. It connects a computer to a phone line. A modem converts digital signals (a stream of bits) to analogue signals ( a continuous wave) which is the format used in telephone lines. That analogue signal is sent through the telephone lines.

Figure 1.4 shows how external modems are used with computers to send and receive data over the telephone network. There are internal modems that fit to an expansion slot on the motherboard. Modems have different transmission speeds, measured in bits per second (bps), or in baud.

Figure 1.4: Modems converting digital bit streams to analogue signals and vice versa

Image Credit: CPE Wiki

Introduction 2 - Network Interface Cards

Introduction...

  2. Network Interface Cards

The network interface card (NIC) is installed in an expansion slot of the computer. This card (Figure 1.2) connects the computer to a network, and contains information on the computer's location and also instructions for sending and receiving data over the network.

It adds a serial port to the computer and the port connects directly to a network. NIC converts the computers' low power signals to high power signals that can be transmitted over the network. NIC's speed is measured in megabits per second (Mbps).

Figure 1.2: Network Interface Card (NIC)

Introduction 1 - Computer Networks

INTRODUCTION TO NETWORKING

Introduction

This first post will provide an overview about how simple network is built for data communication. Computers connect to networks either by using a modem (external or internal) or a network interface card (NIC). After that we will consider different types of networks available and compare them. Data transmission takes place over some kind of transmission medium. You will also learn about different transmission media commonly in use today. The 4^th section will discuss two basic methods of building a network (i.e. client server networking and peer-peer networking) in an office or a work place for resource sharing. 

Data Communication

Data communication is the study of how the digital data is transferred. To put it simply, it is the transfer of bits in serial form outside a computer through a transmission medium such as wires, or electro-magnetic waves. It is important to pay more attention to the word outside, because managing data when it is moving between computers is different to, and harder than, managing it within the computer.