Networking and Telecommunication

 Networking and Telecommunication

 

Questions and Answers [70]

 

1.       Communication

 Communication is sending and receiving information between two or more persons.

 2.       Telecommunication [MFT 2075]

 Telecommunication is a system of transmission of sounds, images, texts or data in the form of 

  electronic signals.

 3.       Data Communication [SLC 2067]

 

Data communication is a process of transferring data electronically from one place to other using different transmission mediums. Eg. E-Mail, Chat and phone calls.

 

 

Components of Data Communication.

 i) Data           ii) Sender            iii) Medium            iv) Receiver                v) Protocol

 4.       Medium

 A path through which the sender makes communication to the receiver is known as medium.

 5.       Protocol [MFT 2075]

 

Protocol is a set of rules by which computers on the network communicate with each other. E.g. TCP/IP, SMTP, HTTP etc.

 

6.       Data Transmission Mode [MF 2076]

 

Data transmission mode is the way of transmission of data from one location to another. There are three types of transmission mode:

 

i)  Simplex mode

 

ii)  Half duplex mode

 

iii)  Full Duplex Mode

 

7.       Simplex mode [MF 2076]

 

The transmission mode in which transmission of data can take place in one direction only is called simplex mode. E.g.: Newspaper, Radio and Television.

 

8.       Half duplex mode [MF 2076]

 

The transmission mode in which transmission of data can take place in both directions but only in one direction at a time is called half duplex mode.

 

E.g.: Wireless handset and walkie-talkie.

 

9.       Full duplex mode [MF 2076]

 

The transmission mode in which data can be transmitted in both directions simultaneously is called full duplex mode.

 

E.g.: Telephone, internet etc.

 

10.   Bandwidth [SEE 2066 S]

 

Bandwidth can be defined as the maximum volume of data that can be transmitted through a communication system.

 

We can measure bandwidth in digital devices by bits per second and in analogue devices by cycles per second or Hertz (Hz).

                                                                                                          

 

11.   Transmission medium / Communication Channel [SLC 2070 S] [SEE 2074 U] [MM 2076] [MFT 2075] Transmission medium is a pathway that can transmit information from a sender to a receiver through wired or wireless medium on a network.

 

The types of communication medium are:

 

i)  Guided Medium (Bounded or Wired)

 

ii)  Unguided Medium (Unbounded or Wireless)

 

12.   Guided medium [SEE 2074 U]

 

The transmission media which comprises of cables or wires through which data is transmitted is called guided medium. They are called guided since they provide a physical channel from the sender device to the receiver device. The signal travelling through these media are bounded by the physical limits of the medium.

 

E.g.: twisted pair cable, co-axial cable, fibre optics cable, etc.

 

13.   Features of guided media: [SEE 2075]

 

-  Data transmits through the physical cable or fixed path

 

-  Data transmission rate is higher.

 

14.   Unguided medium [SEE 2074 U]

 

The transmission media which transfer data in the form of electromagnetic waves that do not require any cables for transmission is called unguided medium. These media are bounded by geographical boundaries.

 

E.g.: radio wave, microwave, infrared etc.

 

15.   Twisted pair cable

 

A pair of wires twisted with each other is known as twisted pair cable. A set of four pairs of twisted wires are bundled to form cable. These are the most common medium for LAN. Wires are twisted with each other so as to reduce crosstalk (A disturbance caused by electromagnetic interference, along a circuit or a cable pair).

 

Its types are:

 

a) Unshielded Twisted Pair Cable b) Twisted Pair Cable

 

16.   Unshielded twisted pair (UTP)

 

Unshielded twisted pair is a popular type of cable that consists of two unshielded wires twisted around each other which are used in telephone wiring and local area networks (LANs). It is called unshielded because it has no additional foil wrap, or shield.

 

RJ-45 connector is commonly used with unshielded twisted pair.

 

17.   Shielded twisted pair (STP)

 

Shielded twisted pair is a type of copper telephone wiring in which each of the two copper wires are twisted together and coated with an insulating coating. The extra covering in shielded twisted pair wiring protects the transmission line from electromagnetic interference.

 

D-shell connectors are used with shielded twisted pair.

 

18.   Co-axial cable

 

Coaxial (or “coax”) cable is a common type of cable used for transmitting data over long distances. They are most commonly used to transmit cable TV and Internet signals.

 

The connectors used with co-axial cables are BNC, T-connectors and terminators in bus topology. 10 Mbps is the maximum speed of co-axial cable.

                                                                                                            

 

19.   Fiber optic cable

 

Fiber optics cable is one of the costlier cables used in data communication which uses light to carry a data signal through the cable.

 

The connectors used in fiber optics are Screw Mounted Adaptors (SMA), Spring-loaded Twist (ST), SC and FC. It is costlier to maintain, produce and install.

 

20.   Radio wave transmission

 

The transmission making use of radio waves through air is called radio wave transmission. It provides low bandwidth for data communication.

 

Radio, TV, cellular phones etc. uses radio transmission in one form or another. The radio waves can travel through walls and through an entire building. Depending upon the frequency, they can travel long distance or short distance. It does not require line of sight for data transmission

 

21.   Microwave transmission

 

Microwave is a line-of-sight wireless communication technology that uses high frequency beams of radio waves to provide high speed wireless connections that can send and receive voice, video, and data information. Microwaves do not pass through buildings. So, indoor receivers cannot be used effectively.

 

It provides higher bandwidth for data communication. It requires line of sight for data transmission.

 

22.   Infrared transmission

 

Infrared Transmission is the transmission of data or voice information over infrared (IR) light over short ranges. It requires line-of-sight and is unable to break through walls.

 

23.   Computer network [SLC 2066] [SLC 2068 S] [SLC 2069 S] [SLC 2070 S] [SLC 2071 S] [SEE 2074] [MF 2076]

 

A computer network means two or more computers connected with each other to share data, hardware, software and other resources.

 

24.   Advantages of computer network [SLC 2065 S] [SLC 2069] [SLC 2071 S] [SEE 2075 S2] [MF 2076] [MFT 2075]

 

a)       Computer in a network can access the network-connected hardware devices like printers, disk drives, etc.

 

b)      Data in a network environment can be updated from any computer. Updated data can be accessed by all computers on the network.

 

c)       Computers in a network system share different software packages.

 

d)      Information can be exchanged rapidly in computer network.

 25.   Disadvantages of computer network [SEE 2075 S2] [MF 2076] [MFT 2075]

 a)       The sharing of information may leak the privacy of other clients.

 b)      The networking cost is high

 c)       If hardware or software malfunctions, it affects the whole network.

 d)      Data and information may be stolen by computer hackers if the security of network is not reliable.

 26.   Services of computer network.

 a)       Directory services

 b)      File services

 c)       Application services

 d)      Communication services