DATA COMMUNICATION AND COMPUTER NETWORK Manual (314318)

February 06, 2025

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DATA COMMUNICATION AND COMPUTER NETWORK (314318)

Manual Answers

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data networking
Data Communication and Computer Network

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Practical No.1 

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Q 1. Explain use of Amplitude Shift keying (ASK)

Ans. Amplitude Shift Keying (ASK) is a digital modulation technique where the amplitude of a carrier wave is varied in accordance with the binary data signal while keeping the frequency and phase constant.

Uses of Amplitude Shift Keying (ASK)

Amplitude Shift Keying (ASK) is used in various digital communication systems due to its simplicity and ease of implementation. Some key applications include:

a. Optical Fiber Communication

  • Used in On-Off Keying (OOK) for transmitting digital signals over optical fiber.
  • Common in LED-based optical communication systems.

b. Radio Frequency Identification (RFID)

  • ASK is widely used in RFID systems for short-range wireless communication, such as in access cards, toll collection, and inventory management.

c. Low-Speed Wireless Communication

  • Used in remote-control systems like garage door openers and wireless key fobs.
  • Employed in near-field communication (NFC) applications.

d. Early Dial-up Modems

  • ASK was used in early modem technologies (such as Bell 103 standard) to transmit digital data over telephone lines.

e. AM Radio Broadcasting

  • While AM (Amplitude Modulation) is an analog technique, the concept is similar to ASK in digital communication.

f. Embedded Systems and IoT Devices

  • ASK is used in low-power IoT devices where bandwidth and power consumption are limited.

g. Data Transmission in Satellite Communication

  • ASK is used in some low-power satellite communication systems, especially in telemetry applications.\

Q 2. Explain advantages of Amplitude Shift keying (ASK)

Ans.

Advantages of Amplitude Shift Keying (ASK)

  1. Simple Implementation

    • ASK is easy to implement using basic circuit components like modulators and demodulators.
    • Requires minimal hardware, making it cost-effective.

  2. Low Bandwidth Requirement

    • Compared to Frequency Shift Keying (FSK) and Phase Shift Keying (PSK), ASK requires less bandwidth, making it efficient for low-data-rate applications.

  3. Efficient for Short-Range Communication

    • Works well for short-distance wireless communication, such as RFID systems, remote controls, and NFC applications.

  4. Compatible with Optical Communication

    • ASK is widely used in On-Off Keying (OOK) for fiber-optic communication, where simple binary encoding is beneficial.

  5. Low Power Consumption

    • Ideal for low-power applications like IoT devices and embedded systems where power efficiency is crucial.

  6. High Data Transmission Rate in Ideal Conditions

    • In environments with low noise and interference, ASK can achieve higher data rates compared to some other modulation schemes.


Q 3. Explain modulation and demodulation of ASK

Ans. 

ASK Modulation & Demodulation 

Modulation (ASK Generation)

  • The amplitude of a carrier signal is varied based on binary data (1s and 0s).
  • A high amplitude represents binary '1', and low/zero amplitude represents binary '0'.
  • Uses a carrier generator, multiplier circuit, and binary data source.

Demodulation (ASK Detection)

  • Extracts the original binary data from the received ASK signal.
  • Coherent Demodulation: Uses a synchronized carrier for accurate detection.
  • Non-Coherent Demodulation: Uses an envelope detector to detect amplitude variations.
  • A low-pass filter removes noise, and a decision circuit determines 1s and 0s.


Q 4. Explain working Amplitude shift keying (ASK)

Ans. 

Working of Amplitude Shift Keying (ASK) 

Amplitude Shift Keying (ASK) works by varying the amplitude of a high-frequency carrier wave according to the digital data while keeping the frequency and phase constant.

Working Principle:

  1. Modulation:

    • Binary '1' → High-amplitude carrier signal.
    • Binary '0' → Low/zero-amplitude carrier signal.

  2. Transmission:

    • The ASK signal is transmitted over a communication channel (wired or wireless).

  3. Demodulation:

    • The receiver extracts the amplitude variations.
    • A detector circuit or envelope detector recovers the original binary data.

Key Points:

  • Simple to implement but prone to noise.
  • Used in RFID, optical fiber (OOK), and low-power wireless systems.


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Practical No. 4

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Q 1. Which tool is used to test network cable?

Ans. 

A Cable Tester is used to test network cables.

Common Types:

  1. Continuity Tester – Checks for broken or miswired connections.
  2. Wire Map Tester – Identifies incorrect wiring in twisted pair cables.
  3. TDR (Time-Domain Reflectometer) – Locates faults and measures cable length.
  4. Fluke Network Tester – Advanced tool for testing speed, signal quality, and cable integrity.


Q 2. Explain Use of Cable in networking

Ans. 

Use of Cables in Networking 

Network cables are used to transmit data between devices in a network, such as computers, routers, switches, and servers.

Common Uses:

  1. Data Transmission – Transfers digital data between network devices.
  2. Internet Connectivity – Connects devices to the internet via routers/modems.
  3. Device Communication – Links computers, printers, and servers in a LAN.
  4. Power over Ethernet (PoE) – Provides both power and data to devices like IP cameras and VoIP phones.

Types of Network Cables:

  • Twisted Pair (Ethernet cables – Cat5e, Cat6, etc.)
  • Coaxial Cable (Used in cable internet and CCTV)
  • Fiber Optic Cable (High-speed, long-distance communication)


Q 3. Explain types of Transmission medium

Ans. 

Types of Transmission Medium in Networking

Transmission medium refers to the physical or wireless path used to transmit data between devices. It is classified into guided (wired) and unguided (wireless) media.

1. Guided (Wired) Media – Uses physical cables for data transmission.

  • Twisted Pair Cable – Used in Ethernet networks (e.g., Cat5e, Cat6).
  • Coaxial Cable – Used in cable TV and older computer networks.
  • Fiber Optic Cable – High-speed data transmission over long distances.

2. Unguided (Wireless) Media – Uses electromagnetic waves to transmit data.

  • Radio Waves – Used in Wi-Fi, Bluetooth, and mobile networks.
  • Microwaves – Used in satellite and long-distance wireless communication.
  • Infrared (IR) Waves – Used in remote controls and short-range communication.


Q 4. State the purpose to use RJ45 connector.

Ans. 

The RJ45 connector is used to connect Ethernet cables (such as Cat5e, Cat6) to network devices, enabling communication in local area networks (LANs).

Purpose of RJ45 Connector:

  1. Network Connectivity – It is primarily used for wired network connections (Ethernet).
  2. Data Transmission – Allows the transmission of data between devices like computers, routers, switches, and hubs.
  3. Standardization – It is the industry standard for most Ethernet networks.
  4. Support for High Speeds – Supports data speeds up to 10Gbps (depending on the cable type).


Q 5. Give the names of RJ45 pinout for each pin along with pin number.

Ans. 

Color Coding for T568A and T568B Standards

Here’s a comparison of the color coding for the T568A and T568B wiring standards used for Ethernet cables (RJ45 connectors):

T568A Standard (Color Code)

Pin Number
Wire Color
1
White/Green
2
Green
3 White/Orange
4 Blue
5
White/Blue
6 Orange
7 White/Brown
8 Brown

T568B Standard (Color Code)

Pin Number
Wire Color
1 White/Orange
2 Orange
3 White/Green
4 Blue
5
White/Blue
6
Green
7 White/Brown
8 Brown

Key Differences

  • The primary difference between T568A and T568B is the order of the green and orange wire pairs.

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Practical No. 6

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Q 1. Write down applications of TDM.

Ans.

Applications of Time Division Multiplexing (TDM) 

  1. Telecommunication Systems: Used to combine multiple voice channels (e.g., in T1/E1 lines).
  2. Cellular Networks: Enables multiple calls/data over the same frequency (e.g., GSM, CDMA).
  3. Data Communication: Facilitates high-speed data transfer (e.g., ISDN).
  4. Voice and Data Integration: Combines voice and data in VoIP systems.
  5. Broadcasting: Combines multiple audio/video signals for radio/TV.
  6. Digital Subscriber Lines (DSL): Allocates time slots for voice and data over the same line.
  7. Television Transmission: Used in digital video broadcasting systems.

TDM helps efficiently use available bandwidth and share communication channels.


Q 2. Why TDM more suitable for digital signal transmission.

Ans. 

  1. Time-Based Division: TDM divides time into slots, which fits well with the discrete nature of digital signals (on/off states).
  2. Efficient Use of Bandwidth: TDM allows multiple digital signals to share the same channel without interference, optimizing bandwidth usage.
  3. Synchronization: Digital signals are easier to synchronize in time slots, reducing noise and errors.
  4. Compatibility with Digital Systems: TDM naturally integrates with digital technology like ISDN and VoIP for efficient data transmission.

In short, TDM is efficient, easy to synchronize, and aligns well with digital systems’ discrete and time-sensitive nature.


Q 3. State the function of commutator and decommutator switches.

Ans. 

Function of Commutator and Decommutator Switches

  1. Commutator Switch:
    • Function: It connects and directs different input signals to the output during multiplexing. In digital communication, it combines multiple signals into one transmission line by assigning them different time slots (TDM).
  2. Decommutator Switch:
    • Function: It reverses the process of commutation by separating the multiplexed signal back into its original individual channels during demultiplexing.

In short, the commutator combines signals, and the decommutator separates them.

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