Back to: o level computer notes
Unit Objectives
Definition of terminologies associated with computer communication
- Importance of computer communication
- Limitations of computer communication
- Transmission media types.
- Wireless Broadcast
- Data Transmission
- Networking hardware
- Communications software
- Network topologies
Computer Communication
- Computer communication is the transmission of data and information over a channel between two computers.
- Communication between computers can be as simple as cabling two computers to the same printer.
Computer Network
A computer Network is a connection of two or more computers and devices connected by channels so that they can communicate with each other and share resources:
Examples of resources
- Data, a single internet connection,
- Software, peripheral devices, processing power.
Encoding
This is the process through which Information (e.g. data, text, voice or video) from the sending device is converted into signals.
Transmission
This is the process through which the signals are broadcast/ sent out through the medium to the receiving device.
Decoding
This is the process through which the signals are converted back into the information in its original form in the receiving device.
- Telecommunication refers to the transmission of data and information over a long distance, eg television
- Teleprocessing: This refers to access and modification of computer files located elsewhere.
- Downloading: To Download is to transfer a file to your computer from another.
- Uploading means transferring a file from one computer to another.
- Throughput refers to the rate of how much data is moved during a certain amount of time.
- The amount of signals that can travel over a communications channel sometimes is called the Bandwidth. The higher the bandwidth, the more data and information the channel can transmit.
Data Encryption
- This is Process of converting data into coded form (cypher text) to prevent it from being read or understood by unauthorized people.
- Encrypted data is difficult to decode without a secret key
Communications Software
This refers to a set of instructions (software) needed by a computer before it starts sending and receiving data from other computers.
Importance of computer communication
- It allows sharing of hardware like printers.
- It allows sharing of software between two or more computers, hence reducing on cost.
- It allows sharing and transfer of data and information stored on other computers on the network.
- Facilitate communications between people e.g. through electronic-mail, Mobile phones,e.t.c.
- Computer communication has security & tight control measures over data access.
- It enables online learning and collaborative research.
- It allows access to common databases for example in banks.
- Has enabled improved travel service through ebookings and e-reservation.
- Provides for online employment e.g. telecommuting.
Limitations of computer communication
- Data theft. If a computer is a standalone, physical access becomes necessary for any kind of data theft. However, if a computer is on a network, a computer hacker can get illegal access.
- Rapid Spread of Computer Viruses: If any computer system in a network gets infected by computer virus, there is a possible threat of other systems getting infected.
- Expensive Set Up: The initial set up cost of a computer network can be high depending on the number of computers to be connected.
- Dependency on the Main File Server: In case the main File Server of a computer network breaks down, the system becomes useless.
- Exposure to External Exploits. Someone on a different computer can send data to the computer in such a way as to attack it – make it lock up or crash, make it slow down, or even take control of it.
- Automatic Downloads. If a computer is connected to a network, it’s easier to download and install software from the network onto the computer without any human intervention. If the new software hasn’t been tested, it could cause unpredictable behavior.
- Computer Networks can Fail. Computer networks can be so powerful and useful that it is very vital for them to be used. All of the computers in an office building might become completely useless if a single network component fails.
Transmission media (Channels)
- Transmission media refers to the physical materials that are used to transmit data between computers. (Guided)
- For communications between computers that are linked by cable, there are three choices:
- Twisted wire,
- Coaxial cable,
- Fiber optic line.
