Computer Network and Communication Media

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.

Advantage of Computer Network

• 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.

Disadvantages of Computer Network

• 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.