## Note on Computer Network and Communication Media

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#### Computer Network

The group of interconnected computers through transmission media in-order to communicate and share resources like hardware, data and software is known as communication media. It is a system for communication between networks. The computers in the network may be connected through cables,telephone-lines, beams etc.

• The computers on the network can share hardware devices like printer, scanner etc.
• Data and software can be shared within the computer on the network.
• Files can be transferred from one computer to another computer.
• Computers in the network can communicate with each other.

• Data and information maybe stolen by computer hackers.
• If any computer in the network get affected by the virus, there is high chance of spreading computer virus.
• Computers on the network have to depend on the server.

#### Types of communication media

There are two main types of communication channels. They are:

1. Guided or Bounded or Wired Communication Media

A transmission media where data signals are transmitted along a specific path through cable is known as Guided Transmission Media. It transfer data from one place to another with the help of wire. There are three types of cables used for wired network. They are:

• Twisted Pair Cable

The twisted pair cable consists of a pair of insulated copper wire twisted around each other. The number of twisted pair may 1, 2, 4 or more. The twisted pair cable is mostly used for connecting computers on the network.

The twisted pair cable comes into two categories:

1. Unshielded Twisted Pair (UTP):A UTP cable is one of the most popular LAN cables. This cable consists of 4 twisted pairs of metal wires (means there are 8 wires). Adding RJ-45 connector at both ends of the cable, it becomes a LAN cable that we generally use.
2. Shielded twisted Pair (STP):A shielded twisted pair cable (also known as IBM Type I) is similar to UTP but it has metallic covering placed just underneath the plastic casing. It is more expensive than UTP cables. STP cable offer the best protection from interference. It can support data transfer rate from 16 to 500 Mb/s (millions of bit per second).
• Co-axial cable

Coaxial cable have wide bandwidth and noise immunity. These are widely used in long distance telephone lines. It's transmission speed is much higher than twisted pair cables.

• Fiber optic cable

Fiber optic cables are made up of plastic or glass fibers and gives high quality transmission of signal at a very high speed. Fiber optic cable transmission are not affected by electromagnetic interference.These can be used to communicate either analog or digital signals. These are most commonly used for point to point one way communication.

2. Unbounded or Unguided or Wireless Communication Media

The way to transfer data without the help of wire is called Unguided media.

Types of Unguided Media

• Microwave: The way to transfer data straightly from one point to another point in the way of light in the universe is called microwave system.
• Radio wave: Radio wave transmissions are used for communication between computers in inaccessible locations or for short range communications. The other benefit is the responsibility of reaching rural and hilly area which are not covered by land telephone line.
• Satellite: Satellite communications are like microwave and has relay stations in the sky. Transponders on the satellite are used to receive and re-transmit signals sent from earth stations. A transponder has a very high capacity and can handle more than 400 channels.

• There are two types of communication media. They are Guided or Bounded or Wired Communication Media and Unguided or Unbounded or Wireless Communication Media.
• The twisted pair cable consists of a pair of insulated copper wire twisted around each other.
• A transmission media where data signals are transmitted along a specific path through cable is known as Guided Transmission Media.
• The group of interconnected computers through transmission media in-order to communicate and share resources like hardware, data and software is known as communication media.
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### Very Short Questions

A communication media is the path through which data, information and files transfers from one computer to other computer in the form of electromagnetic wave i.e. electric signals.
The main two communication media are as follows:

• Guided Transmission Media
• Unguided Transmission Media

Guided transmission media is such a transmission media where signals are transmitted along a specific path through cable.
Any three guided transmission media are as follows:

• Coaxial Cable
• Twisted Pair Cable
• Fiber Optical Cable

Unguided transmission media is such a media where information is transmitted by sending electromagnetic signals through free space, as the signals are not guided in any specific direction or inside any specific medium.
Any three unguided transmission media are:

• Infrared
• Microwave

An optical fiber cable is a cable containing one or more optical fibers. The optical fiber elements are typically individually coated with plastics layers and contained in a protective tube suitable for the environment where the cable will be deployed. The data travels at a very high speed in the form of light.

A type of wire that consists of a center wire surrounded by insulation and then a grounded shield of braided wire. The shield minimizes electrical and radio frequency interface. Coaxial cabling is the primary type of cabling used by the cable television industry and is also widely used in computer networks, such as Ethernet.

An UTP cable is one of the most popular LAN cables. This cable consists of 4 twisted pairs of metal wires(that means there are 8 wires in the cable). RJ45 connectors are used in UTP cables.

The most powerful computer on the network, which does all the processing for the user is known as host computer.

Terminal is a specialized network device on a host-based network that transmits the data entered by the user to the host for processing and displays the results.

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• ### Which of the following is an example of unbounded communication media?

Microwave
UTP
Fiber Optics
Co-axial Cable
• ### What is the full form UTP?

Uniform Transferred Protocol
Unshielded To Pair
Unshielded Twisted Pair
Unshielded Transfer Pair
• ### Twisted Pair is an example of :

Guided Communication Media
Unguided Communication Media
Unbounded Communication Media
Wireless Communication Media

Micro wave
Satellite
None of them
• ### ______________ are made up of plastic or glass fibers and gives high quality transmission of signal at a very high speed.

Unshielded Twisted Pair
Shielded twisted Pair
Coaxial cable
Fiber optic cables
• ### What is Transmission Media?

Powerful and wide ranging network.
Channel through which the data travels in a network.
One direction topology.
Network where there is no central authority.
• ### What is Coaxial Cable?

Cable used on ARC net and IBM terminals
Cable made up of single upper wire
Cable used in coax ethernet networks
Cable used frequently as a backbone
• ### What is fiber optics?

Major networks system that support fiber-optic cabling.
Common type of network cable.
Cable used on ARC net and IBM terminals.
Channel through which the data travels in a network.
• ### What is twisted pair cable?

Cable used on ARC net and IBM terminals
Channel through which the data travels in a network
Common type of network cable
Major network system that support fibre cabling