Thursday 1 June 2017

CBSE Class 12 - Computer Science / Informatics Practices - Computer Networking - Data Transmission Media - Q and A (#cbseNotes)

Data Transmission Media

Computer Networking

Class 12 - Computer Science / Informatics Practices

Q & A

CBSE Class 12 - Computer Science / Informatics Practices - Computer Networking - Data Transmission Media - Q and A (#cbseNotes)

Q: Define transmission media.

Answer: The means or channel through which we send our data from one place to another are called transmission media.

Q: What are different categories of transmission media?

Guided or Wired Media- Examples are
Twisted Pair Cable
Co-axial cable
Fibre active cable

Unguided or Wireless Media - Examples are:

Q: Define baud.

Answer: Baud is used as measurement for the information carry of a communication channel. It is measured in Kbps (kilobits Per Second), KBPS (Kilo Byte Per Second), and Mbps (Mega bits Per Second )

Q: Write a short note about twisted pair cable. What are its advantages and disadvantages?

Twisted Pair Cable
credits: Baran Ivo, Wikimedia
Answer: It consists of two identical 1 mm thick copper wires insulated and twisted together. The twisted pair cables are twisted in order to reduce crosstalk and electromagnetic induction.

(i) It is easy to install and maintain.
(ii) It is very inexpensive

(i) It is incapable to carry a signal over long distances without the use of repeaters.
(ii) Due to low bandwidth, these are unsuitable for broadband applications.

Q: What is a co-axial cable? What are its advantages and disadvantages?

co-axial cable
By Tkgd2007 (Own work) [CC BY 3.0 ],
via Wikimedia Commons

Answer: It consists of a solid wire core surrounded by one or more foil or braided wire shields, each separated from the other by some kind of plastic insulator. It is mostly used in the cable wires.

(i) Data transmission rate is better than twisted pair cables.
(ii) It provides a cheap means of transporting multi-channel
television signals around metropolitan areas.

(i) Expensive than twisted pair cables.
(ii) Difficult to manage and reconfigure.

Q: How does optical fibre transmit data? Mention its advantages and disadvanatges.

fibre optics
Answer: An optical fibre consists of thin silicon glass fibers that can carry information in the form of visible light. Fiber optic cables have the highest data carrying capacity of any wired medium i.e. 50 terabits per second (tps).

(i) Transmit data over long distance with high security.
(ii) Data transmission speed is high
(iii) Provide better noise immunity
(iv) Bandwidth is up to 10 Gbps.

(i) Expensive as compared to other guided media.
(ii) Need special care while installation

Q: Write a short not on radio wave transmission.

Answer: Radio Wave is an electromagnetic wave with a wavelength between 0.5 cm and 30,000m. The transmission making use of radio frequencies is termed as radio-wave transmission

(i) Radio wave transmission offers mobility.
(ii) It is cheaper than laying cables and fibers.
(iii) It offers ease of communication over difficult terrain.

(i) Radio wave communication is an insecure communication.
(ii) Radio wave propagation is susceptible to weather effects like rains, thunder storms etc.

Q: What is microwave based data transmission?

Answer: Microwaves are high energy radio waves that are used for line of sight communication. Microwave radio energy travels largely in straight lines.

1. Suitable for high speed, long distance and overseas communication.
2. No need for laying cable.

1. Micro wave communication is an insecure communication.
2. Microwave propagation of waves is susceptible to weather effects like Rain, thunder
3. Only straight line transmission is possible.

Q: What is Satellite link transmission?

Answer: The satellite transmission is also a kind of line of sight transmission that is used to transmit signals throughout the world. Satellites are now extensively used for communication purposes. Two major communication satellite architectures are used commonly i.e.

CBSE Class 12 - Computer Science / Informatics Practices - Computer Networking - Data Transmission Media - Q and A (#cbseNotes)

geostationary satellites and
low earth orbit satellites (LEOS)

(i) Area covered is quite large.
(ii) No line of sight restrictions such as natural mountains, tall building, towers etc.
(iii) Earth station which receives the signals can be fixed position or relatively mobile.

(i) Very expensive as compared to other transmission mediums.
(ii) Installation is extremely complex.
(iii) Signals sent to the stations can be tampered by external interference.

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