Transmission medium - Guided Media and Unguided Media [Computer Science - Grade X - New Syllabus]

 

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)

 

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.

 

Features of guided media:  [SEE 2075]

a)      Data transmits through the physical cable or fixed path

b)     Data transmission rate is higher.

 

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.

 

Guided VS Unguided Media

Guided Medai	Unguided Media
Guided media is a medium that sends signals through a solid physical path.	Unguided media is a medium that transmits signals through free space.
There is a specific direction to send signals.	There is no particular direction to send signals.
Used in wired transmission	Helps wireless transmission
Twisted pair, coaxial cable, and fiber optics	Radio wave, microwave, and infrared

 

 

 

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

 

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.

 

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.

 

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    bps is the maximum speed of co-axial cable.

 

 

 

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.

 

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

 

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.

 

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.

Data Communication - Data Transmission Mode - Bandwidth [Computer Science - Grade X - New Syllabus]

 

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

 

Telecommunication [MFT 2075]
Telecommunication is a system of transmission of sounds, images, texts or data in the form of electronic signals.

 

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

 

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

 

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.

 

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

 

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.

 

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.

 

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.

 

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).

Computer Security – SEE Computer Science – Grade X [New Course] #2076B.S. #Solved Objectives of Asia Publications

 Computer Security – SEE Computer Science – Grade X [New Course] #2076B.S. #Solved Objectives of Asia Publications

1.               Fill in the blanks:

 Set 1

 a)     Computer Security is the process of preventing and detecting unauthorized use of your computer.

b)     Confidentiality refers to protecting information from disclosure.

c)     Computer Emergency Response Team (CERT) has defined threats as “any circumstances or events

that have potential to cause harm to a system or a network.”

d)     A firewall is a system design to prevent unauthorized access to or from a private network.

e)     Antivirus software is a program designed to detect and remove viruses from the computer system.

 

Set 2

 

a)     Hardware security protects the machine and peripheral hardware from theft, electronic, intrusion

and damage.

b)     The temperature in the computer system should be maintained between 21⁰C to 24⁰C.

c)     Security lighting and closed-circuit television cameras are the methods of hardware protection.

d)     UPS is a device that allows your computer to keep running for at least a short time when the primary

power source is lost.

e)     Voltage regulator is a device or circuit that maintains a load voltage nearly constant over a range of

variations of input voltage and load current.

 

 

2. Tick the correct response and correct the wrong one:

 

Set 1

 

a)     Security attacks comprise all actions that breaches the computer security. True

b)     Information Security programs are build around 3 objectives, commonly known as  CIA

(Confidentiality, Integrity, Availability). True

c)     Availability refers to ensuring that the data or information is not corrupted or modified by

unauthorized users. False

d)     Firewalls prevent unauthorized internet users from accessing private networks connected to the

internet, especially intranets. True

e)     The encrypted information is called plain text. False

 

Set  2

 

a)     Routine servicing of hardware is a must to keep equipment in good operating condition and to find and correct problems before they develop into severe malfunctions. True

b)     The temperature in the computer system should be maintained between 31°C to 34°C. False

c)     Computer equipment should be used and stored at a relative humidity of 50 percent with 5 percent variation. True

d)     Security lighting and closed-circuit television cameras are the methods of software protection. False

e)     A computer requires a constant source of electrical power.  True

 

 

3. Write the technical terms for the following statements:

 

Set  1

 

a)     The practice of preventing unauthorized access, use, disclosure, disruption, disruption, modification, inspection, recording or destruction of information. Information security

b)     A set of rules designed to enhance computer security by encouraging users to employ strong passwords and use them properly. Password policy

c)     The process of identifying individuals for authentication. Biometric

d)     A system designed to prevent unauthorized access to or form a private network. Firewall

e)     The process of converting ordinary plain text into unintelligible text and vice-versa. Cryptography

 

Set  2

 

a)     A program designed to detect and remove viruses from the computer system. Antivirus software

b)     A type of security that protects the machine and peripheral hardware from theft, electronic intrusion and damage. Hardware security

c)     A device that allows your computer to keep running for at least a short time when the primary power source is lost. UPS

d)     A device or circuit that maintains a load voltage nearly constant over a range of variations of input voltage and load current. Voltage regulator

e)     A device that shields computer and other electronic devices from surges in electrical power, or transient voltage, that flow from the power supply. Surge suppressor

 

4. Give the full forms of the following abbreviations:

a)     CIA – Confidentiality, Integrity, Availability

b)     CERT- Computer Emergency Response Team

c)     UPS – Uninterruptible Power Supply

 

5. Select the best answer from the list of choices. [MCQ]

 

            Set-1

 

a.      The ................... threats arise from hackers who intrude into systems posing as authorized users.

i.

Authorization

ii.

Application

iii.

Physical security

iv.

All of the above

b.     ...............is a method of storing and transmitting data in a particular form so that only those for it is intended can resd and process it.

i.

Firewall

ii.

Biometrics

iii.

Cryptography

iv.

All of the above

c.      ....................... protect the machine and peripheral hardware from theft, electronic intrusion and damage.

i.

Information security

ii.

Hardware security

iii.

Software security

iv.

None of the above

 

                    Set-2

 

a.      Some of the methods of hardware protetion are ...................

i.

Fire Alarms

ii.

Security lighting

iii.

Closed-circuit cameras

iv.

All  of the above

b.     The temperature in the computer system should be maintained between .................to............................

i.

210C and 240C

ii.

200C and 250C

iii.

230C and 280C

iv.

None of the above

c.      ........................ is a device that protect your PC against power surges and spikes.

i.

UPS

ii.

Voltage regulator

iii.

Surge suppressor

iv.

All  of the above

 

6. Match the following:

 

a)     Information security	c) The process of preventing and  detecting unauthorized use of your computer
b)     Biometrics	a) The practice of preventing unauthorized access, use, disclosure, disruption,  modification, inspection, recording or destruction of information.
c)     Computer security	b) The process of identifying individuals for authentication.
d)     Cryptography	e) A system designed to prevent unauthorized access to or from a private network.
e)     Firewall	d) The process of converting ordinary plain text into unintelligible text and vice-versa.

 

 #ThankYou Bandana Khadka, Shreyasha Dhakal and Aadesh Rai for Typing support