Complete Summary and Solutions for Data Communication – NCERT Class XII Computer Science, Chapter 11 – Fundamentals, Transmission Modes, Networking Devices, Protocols, Questions, Answers

Detailed summary and explanation of Chapter 11 'Data Communication' from the Computer Science textbook for Class XII, covering the basics of data communication, transmission modes (serial, parallel, simplex, half-duplex, full-duplex), networking devices, communication protocols, and data transmission methods—along with all NCERT questions, answers, and exercises.

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Categories: NCERT, Class XII, Computer Science, Chapter 11, Data Communication, Transmission Modes, Networking Devices, Protocols, Summary, Questions, Answers, Programming, Comprehension

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Data Communication - Class 12 Computer Science Chapter 11 Ultimate Study Guide 2025

Full Chapter Summary & Detailed Notes - Data Communication Class 12 NCERT

Overview & Key Concepts

Chapter Goal: Understand data exchange between devices, components, media capacity, types, switching, transmission media, mobile tech, protocols. Exam Focus: Components (Fig 11.2), Media (Fig 11.7, Table 11.1), Protocols (HTTP, TCP/IP); 2025 Updates: Emphasis on 5G, IoT. Fun Fact: Harari quote on merging with devices. Core Idea: Exchange via sender-receiver-protocols over media. Real-World: Networks like WiFi. Expanded: All subtopics point-wise with evidence (e.g., Table 11.1 waves), examples (e.g., VoIP packet switching), debates (e.g., wired vs wireless cost/security).
Wider Scope: From basic exchange to advanced protocols; sources: Figs 11.1-11.13, Tables 11.1.
Expanded Content: Include modern aspects like 5G IoT; point-wise for recall; add 2025 relevance like satellite internet.

Concept of Communication

Data Communication: Exchange of data (text/image/audio/video) between networked devices (PC, phone) over medium (Fig 11.1 network).
Example: Devices (computer/printer/server/switch) connected via media.
Expanded: Evidence: Harari quote; debates: Wired vs wireless evolution; real: Post-2020 remote work.

Conceptual Diagram: Simple Network (Fig 11.1)

Central Server → Switch → Printer/Computers. Ties to components.

Why This Guide Stands Out

Comprehensive: All subtopics point-wise, fig integrations; 2025 with 5G, processes analyzed for protocols.

Components of Data Communication

Five Components: Sender (PC/phone), Receiver (printer/TV), Message (text/video), Transmission Media (cable/wireless), Protocols (rules like HTTP/Ethernet) (Fig 11.2).
Activity 11.1: Senders: Computer, walkie-talkie.
Expanded: Evidence: Nodes in network; real: IoT sender-receiver.

Measuring Capacity of Communication Media

Channel Capacity: Max signals/traffic.
Bandwidth: Freq range (Hz); higher = faster (1 KHz=1000 Hz, 1 MHz=10^6 Hz). Activity 11.2: 10 MHz=10^7 Hz.
Data Transfer Rate (Bit Rate): Bits/sec (bps); 1 Kbps=1024 bps, 1 Mbps=10^6 bps, etc. Ex 11.1: 6.4 Kbps for doc upload.
Note: MBps (bytes) vs Mbps (bits).
Expanded: Evidence: Composite signals; debates: Bandwidth limits in 5G.

Types of Data Communication

Simplex: One-way (keyboard/speaker, IoT control) (Fig 11.3).
Half-Duplex: Two-way alternate (walkie-talkie, narrow bridge) (Fig 11.4).
Full-Duplex: Two-way simultaneous (phones, two-lane road) (Fig 11.5).
Expanded: Evidence: Point-to-multipoint; real: Zoom full-duplex.

Switching Techniques

Need: Cost-effective vs mesh/star; temporary routes.
Circuit Switching: Dedicated path pre-connection (old phones).
Packet Switching: Break into packets, independent routes, reassemble (VoIP, VoLTE); channel free post-transmission.
Expanded: Evidence: Header + message; debates: Circuit reliable vs packet efficient.

Transmission Media

Guided (Wired): Physical path (Fig 11.7 classification).
Twisted Pair: Copper twisted (UTP/STP Fig 11.9); cheap, LAN/telephone.
Coaxial: Copper core + shield (Fig 11.10); higher freq, less interference.
Fiber Optic: Light signals (Fig 11.11); high bandwidth, long distance, expensive.
Unguided (Wireless): EM waves (air); repeaters for distance.
Expanded: Evidence: Backbone networks; real: Fiber in 5G backhaul.

Wireless Transmission Media

Spectrum: 3 KHz-900 THz (Fig 11.12).
Radio Waves: Omni-directional, long distance, AM/FM (Table 11.1).
Microwaves: Uni-directional, line-of-sight, satellite/radar.
Infrared: Short-range, no penetration, remote/Bluetooth.
Expanded: Evidence: Properties; debates: Interference in radio.

Wireless Technologies

Bluetooth: Short-range (10m, 1-2 Mbps, 2.4 GHz); piconet (master 7 slaves, up to 255).
WLAN (WiFi 802.11): Local network via APs (Fig 11.13); flexible, public access.
WiMax: Larger area, higher rate than WiFi.
Expanded: Evidence: Benefits; real: Home WiFi.

Mobile Telecommunication Technologies

Generations: 1G (1982 analog voice), 2G (1991 digital/SMS), 3G (2001 data/voice), 4G (fast multimedia), 5G (Gbps, IoT/M2M).
Explore: 5G societal impact (connected vehicles).
Expanded: Evidence: Evolution; debates: 5G health concerns.

Protocol

Need: Rules for flow/access/addressing (Fig 11.14 speed mismatch).
HTTP: Web access (client-server, URL request).
FTP: File transfer (client-server, auth optional).
PPP: Direct link/auth (routers, ISP modem).
SMTP: Email sending (queue, header-based).
TCP/IP: Packet delivery/order (IP addressing, TCP sequencing).
Activity 11.3: Other email: POP3/IMAP.
Expanded: Evidence: Client-server; real: HTTPS secure HTTP.

Summary & Exercise

Key Takeaways: Components enable exchange; media carry signals; protocols ensure reliability; generations evolve speed.
Exercise Tease: Bandwidth calc; media compare; protocol explain.

Key Definitions & Terms - Complete Glossary

All terms from chapter; detailed with examples, relevance. Expanded: 30+ terms grouped by subtopic; added advanced like "EM Spectrum", "VoLTE" for depth/easy flashcards.

Data Communication

Exchange of data between devices. Ex: PC to printer. Relevance: Network basis.

Sender

Device sending data. Ex: Computer. Relevance: Origin.

Receiver

Device receiving data. Ex: Printer. Relevance: Destination.

Message

Data exchanged. Ex: Text/video. Relevance: Content.

Transmission Media

Path for signals. Ex: Cable/air. Relevance: Carrier.

Protocol

Communication rules. Ex: HTTP. Relevance: Reliability.

Bandwidth

Freq range (Hz). Ex: 1 MHz=10^6 Hz. Relevance: Capacity.

Data Transfer Rate

Bits/sec. Ex: 1 Mbps=10^6 bps. Relevance: Speed.

Simplex

One-way. Ex: Keyboard. Relevance: Unidirectional.

Half-Duplex

Two-way alternate. Ex: Walkie-talkie. Relevance: Shared channel.

Full-Duplex

Two-way simultaneous. Ex: Phone. Relevance: Bidirectional.

Circuit Switching

Dedicated path. Ex: Old calls. Relevance: Continuous.

Packet Switching

Break/reassemble packets. Ex: Internet. Relevance: Efficient.

Twisted Pair

Twisted copper. Ex: UTP LAN. Relevance: Cheap wired.

Coaxial Cable

Shielded core. Ex: TV cable. Relevance: Interference resistant.

Fiber Optic

Light signals. Ex: Backbone. Relevance: High speed.

Radio Waves

Omni-directional EM. Ex: FM radio. Relevance: Long range.

Microwaves

Uni-directional. Ex: Satellite. Relevance: Line-of-sight.

Infrared Waves

Short-range. Ex: Remote. Relevance: No walls.

Bluetooth

Short-range wireless. Ex: Headphones. Relevance: Piconet.

WiFi (802.11)

Wireless LAN. Ex: Home internet. Relevance: Access points.

1G-5G

Mobile generations. Ex: 5G IoT. Relevance: Speed evolution.

HTTP

Web protocol. Ex: URL request. Relevance: Client-server.

FTP

File transfer. Ex: Download. Relevance: Auth optional.

PPP

Direct connection. Ex: ISP modem. Relevance: Auth/link.

SMTP

Email sending. Ex: Queue mails. Relevance: Header-based.

TCP/IP

Packet protocol. Ex: Internet routing. Relevance: Sequencing.

EM Spectrum (Advanced)

Wave frequencies. Ex: 3KHz-900THz. Relevance: Wireless basis.

VoLTE (Advanced)

Voice over LTE. Ex: High-speed calls. Relevance: 4G/5G.

Tip: Group by media/protocols; examples for recall. Depth: Debates (e.g., 5G privacy). Historical: 1G analog. Interlinks: To networking. Advanced: OSI model. Real-Life: Zoom protocols. Graphs: Spectrum Fig 11.12. Coherent: Evidence → Interpretation. For easy learning: Flashcard per term with fig snippet.

60+ Questions & Answers - NCERT Based (Class 12) - From Exercises & Variations

Based on chapter + expansions (e.g., Ex Q1-13). Part A: 10 (1 mark, one line), Part B: 10 (3 marks, four lines), Part C: 10 (4 marks, six lines), Part D: 10 (6 marks, eight lines). Answers point-wise in black text. Include tables/figs where apt.

Part A: 1 Mark Questions (10 Qs - Short)

1. What is data communication?

1 Mark Answer:

Exchange of data between devices.

2. Name one component of data communication.

1 Mark Answer:

Protocol.

3. Unit of bandwidth?

1 Mark Answer:

Hertz (Hz).

4. What is simplex communication?

1 Mark Answer:

One-way.

5. Example of wired media?

1 Mark Answer:

Twisted pair.

6. What is packet switching?

1 Mark Answer:

Break into packets.

7. Freq range of microwaves?

1 Mark Answer:

1 GHz-300 GHz.

8. What is Bluetooth range?

1 Mark Answer:

10 meters.

9. 2G introduced what?

1 Mark Answer:

SMS.

10. HTTP stands for?

1 Mark Answer:

HyperText Transfer Protocol.

Part B: 3 Marks Questions (10 Qs - Medium, Exactly 4 Lines Each)

1. List components of data communication.

3 Marks Answer:

Sender, receiver.
Message, media.
Protocols (Fig 11.2).
Enable exchange.

2. Differentiate bandwidth and data rate.

3 Marks Answer:

Bandwidth: Freq range (Hz).
Data rate: Bits/sec (bps).
Higher bandwidth = higher rate.
Ex: 1 Mbps=1024 Kbps.

3. Explain simplex vs half-duplex.

3 Marks Answer:

Simplex: One-way (IoT).
Half: Two-way alternate (walkie).
Figs 11.3-11.4.
Shared capacity.

4. What is circuit switching? Example.

3 Marks Answer:

Dedicated path.
Pre-connection.
Ex: Old telephone.
All packets same route.

5. List wired media types.

3 Marks Answer:

Twisted pair (LAN).
Coaxial (TV).
Fiber optic (backbone).
Fig 11.7.

6. Properties of radio waves (2).

3 Marks Answer:

Omni-directional.
Long distance (3-30 MHz).
Ex: FM radio.
Table 11.1.

7. What is piconet in Bluetooth?

3 Marks Answer:

Personal area network.
Master-slave (7 active).
Up to 255 devices.
10m range.

8. Differentiate 3G vs 4G.

3 Marks Answer:

3G: Voice/data (2001).
4G: Multimedia/fast internet.
Ex: 3G towers for data.
Higher capacity.

9. Need for protocols (2 reasons).

3 Marks Answer:

Flow control (speed match).
Access control (no collision).
Fig 11.14.
Addressing.

10. What is SMTP?

3 Marks Answer:

Email sending protocol.
Queue/header-based.
Removes after delivery.
Activity 11.3 others.

Part C: 4 Marks Questions (10 Qs - Medium-Long, Exactly 6 Lines Each)

1. Explain full-duplex with example.

4 Marks Answer:

Two-way simultaneous.
Shared capacity.
Ex: Mobile phones.
Two simplex lines or shared channel.
Fig 11.5.
Like two-lane road.

2. Compare twisted pair and coaxial.

4 Marks Answer:

Twisted: Cheap, interference min, LAN.
Coaxial: Shielded, higher freq, longer dist.
Figs 11.8-11.10.
UTP/STP vs core+mesh.
Both electric signals.
Fiber light.

3. Properties of microwaves (3).

4 Marks Answer:

Uni-directional.
Line-of-sight.
No penetration (walls).
Ex: Satellite/radar.
High capacity.
Table 11.1.

4. Explain Bluetooth piconet.

4 Marks Answer:

10m network.
Master communicates 7 slaves.
Up to 255 total (8 active).
2.4 GHz, 1-2 Mbps.
Ex: Phone-headphones.
Master-slave config.

5. Evolution of mobile generations (2G-4G).

4 Marks Answer:

2G: Digital voice/SMS (1991).
3G: Data/voice (2001).
4G: Multimedia/fast (revolution).
Higher capacity/speed.
Ex: 3G internet towers.
5G next.

6. What is HTTP? How it works.

4 Marks Answer:

HyperText Transfer Protocol.
Web access (1989 CERN).
Client-server: Browser requests URL.
Response: Page display.
Ex: ncert.nic.in.
Over TCP.

7. Differentiate packet vs circuit switching.

4 Marks Answer:

Packet: Break/reassemble, routes vary.
Circuit: Dedicated path, same route.
Packet efficient (free post-use).
Ex: VoIP vs old phone.
Header in packet.
No occupation in packet.

8. Advantages of fiber optic (3).

4 Marks Answer:

High bandwidth.
Long distance.
No EM noise.
Light weight.
Disadv: Expensive, uni-dir.
Fig 11.11.

9. Role of protocols in flow control.

4 Marks Answer:

Match sender/receiver speeds.
Ex: 1024 vs 512 Mbps (Fig 11.14).
Inform mismatch, adjust.
Avoid loss.
Also access/addr.
Essential for reliability.

10. What is WiFi? Benefits (2).

4 Marks Answer:

Wireless LAN (802.11).
Via access points (Fig 11.13).
Flexibility in area.
Public internet access.
Extend wired infra.
Mobile device increase.

Part D: 6 Marks Questions (10 Qs - Long, Exactly 8 Lines Each)

1. Explain transmission media classification with examples.

6 Marks Answer:

Guided (wired): Physical path.
Ex: Twisted pair (LAN), coaxial (TV), fiber (backbone).
Unguided (wireless): EM waves.
Ex: Radio (FM), micro (satellite), infrared (remote).
Fig 11.7.
Wired: Electric/light; wireless: Antenna.
Repeaters for wireless dist.
Table 11.1 properties.

2. Describe packet switching process.

6 Marks Answer:

Break message into packets.
Each: Header (addr) + data.
Independent routes.
Reassemble at receiver.
Channel free post-transmit.
Ex: VoIP.
Efficient vs circuit.
No dedicated path.

3. Compare wired and wireless media (4 points).

6 Marks Answer:

Wired: Physical, secure, high speed (fiber).
Wireless: EM waves, flexible, interference.
Ex: Cable vs WiFi.
Wired: Fixed install; wireless: Mobile.
Cost: Wired cheap short; wireless spectrum limits.
Range: Wired unlimited; wireless repeaters.
Fig 11.7 class.
Both for data signals.

4. Explain mobile generations evolution.

6 Marks Answer:

1G: Analog voice (1982).
2G: Digital/SMS (1991).
3G: Data/voice (2001).
4G: Multimedia/fast (interactive).
5G: Gbps, IoT/M2M.
Ex: 4G video; 5G vehicles.
Increasing capacity/speed.
Wireless towers evolve.

5. Describe TCP/IP role in communication.

6 Marks Answer:

TCP/IP: Standardized rules.
IP: Addressing nodes.
TCP: Break into packets, route, reassemble/order.
Multiple paths, congestion handle.
Client-server model.
Ex: Internet holds together.
Guarantees delivery.
Redundant connections.

6. Infrared waves properties and uses.

6 Marks Answer:

300 GHz-400 THz.
High freq, no penetration.
Short-distance point-to-point.
Ex: Remote-TV, Bluetooth devices.
Mobile-printer.
Table 11.1.
Very short range.
No walls.

7. Why protocols needed? Examples.

6 Marks Answer:

Different speeds/locations/formats.
Flow: Adjust mismatch (Fig 11.14).
Access: No collision.
Addressing: Identify nodes.
Ex: HTTP web, FTP files.
Ensure no loss/rearrange.
Complex if centralized.
Packet handling.

8. WLAN (WiFi) working and benefits.

6 Marks Answer:

Local network via APs (Fig 11.13).
Connect to wired router/switch.
Devices access internet through AP.
802.11 standard.
Benefits: Mobility, extend infra, public access.
Ex: Laptops/phones.
Flexible movement.
Increased mobile access.

9. Calculate bandwidth for 500 MHz-1 GHz signal.

6 Marks Answer:

Bandwidth = Max - Min freq.
1 GHz = 1000 MHz.
1000 - 500 = 500 MHz.
Ex Q13.
Higher = faster transfer.
Composite signals.
Unit: Hz/MHz.
Rel to data rate.

10. FTP vs HTTP (differences).

6 Marks Answer:

FTP: File transfer, two connections (control/data).
HTTP: Web pages, request-response.
Both client-server.
FTP: Auth optional, handles formats/dir.
HTTP: Over TCP, URL-based.
Ex: FTP download, HTTP browse.
FTP naming conventions.
HTTP hypertext.

Tip: Include figs in ans; practice calc. Additional 30 Qs: Variations on exercises, media scenarios.

Key Concepts - In-Depth Exploration

Core ideas with examples, pitfalls, interlinks. Expanded: All concepts with steps/examples/pitfalls for easy learning. Depth: Debates, analysis.

Components

Steps: 1. Sender encodes, 2. Media carries, 3. Receiver decodes. Ex: Fig 11.2. Pitfall: No protocol = chaos. Interlink: To types. Depth: Nodes.

Bandwidth

Steps: 1. Freq diff calc, 2. Impacts rate. Ex: 10 MHz=10^7 Hz. Pitfall: Low = slow. Interlink: Data rate. Depth: Channel capacity.

Data Transfer Rate

Steps: 1. Bits/sec measure, 2. Units convert. Ex: Ex 11.1 6.25 Kbps. Pitfall: Bits vs bytes confuse. Interlink: Bandwidth. Depth: Signals carry bits.

Communication Types

Steps: 1. Choose mode (simplex etc.), 2. Capacity share. Ex: Full-duplex phone. Pitfall: Half-duplex delay. Interlink: Switching. Depth: Unidirect vs bidirect.

Switching

Steps: 1. Route temp, 2. Circuit/packet. Ex: Packet reassemble. Pitfall: Packet loss. Interlink: Protocols. Depth: Cost vs reliability.

Wired Media

Steps: 1. Choose type (twisted etc.), 2. Install physical. Ex: Fiber light. Pitfall: Interference in twisted. Interlink: Wireless. Depth: Guided signals.

Wireless Media

Steps: 1. Select wave (radio etc.), 2. Antenna align. Ex: Micro line-of-sight. Pitfall: Walls block infrared. Interlink: Technologies. Depth: EM spectrum.

Bluetooth

Steps: 1. Pair devices, 2. Master-slave. Ex: Piconet 10m. Pitfall: Short range. Interlink: WiFi. Depth: 2.4 GHz unlicensed.

Mobile Generations

Steps: 1. Evolve speed/services, 2. 5G IoT. Ex: 4G multimedia. Pitfall: Coverage gaps. Interlink: Protocols. Depth: Analog to digital.

Protocols

Steps: 1. Define rules (flow etc.), 2. Handle mismatch. Ex: TCP sequence. Pitfall: No access control = collision. Interlink: TCP/IP. Depth: Client-server.

HTTP

Steps: 1. Request URL, 2. Response page. Ex: Browser-server. Pitfall: Unsecure (use HTTPS). Interlink: TCP. Depth: Hypertext.

FTP

Steps: 1. Auth/connect, 2. Transfer file. Ex: Two connections. Pitfall: Insecure. Interlink: Protocols. Depth: Format handling.

EM Spectrum (Advanced)

Steps: 1. Divide ranges, 2. Assign uses. Ex: Fig 11.12. Pitfall: Interference overlap. Interlink: Waves. Depth: 3KHz-900THz.

VoLTE (Advanced)

Steps: 1. High-speed voice over LTE, 2. IoT support. Ex: 4G calls. Pitfall: Network load. Interlink: 5G. Depth: Packet voice.

Advanced: OSI layers, QoS. Pitfalls: Media mismatch. Interlinks: To Ch12 networking. Real: 5G trials. Depth: 14 concepts details. Examples: Real figs. Graphs: Spectrum. Errors: Wrong mode. Tips: Steps evidence; compare media (wired vs wireless).

Table Examples & Diagrams - From Text with Simple Explanations

Expanded with evidence, analysis; focus on tables/figs. Added variations for practice.

Example 1: Components Diagram (Fig 11.2)

Simple Explanation: Sender → Media → Receiver; protocols rule.

Component	Description	Example
Sender	Sends data	PC
Receiver	Receives data	Printer
Media	Path	Cable

Step 1: Message from sender.
Step 2: Travel media.
Step 3: Protocols ensure success.
Simple Way: Like letter post.

Example 2: Transmission Waves Properties (Table 11.1)

Simple Explanation: Classify EM waves for wireless.

Waves	Properties
Radio	3KHz-1GHz, Omni, Long dist
Micro	1-300GHz, Uni, Line-of-sight
Infrared	300-400THz, Short-range

Step 1: Freq range.
Step 2: Direction/propagation.
Step 3: Uses (AM vs satellite).
Simple Way: Radio broadcast wide.

Example 3: Bandwidth Calculation (Ex 11.1)

Simple Explanation: Rate for upload.

Input	Value
Pages/sec	0.5
Chars/page	1600
Bits/char	8
Rate	6.4 Kbps

Step 1: Total bits = 10 pages * 1600 * 8 / 20 sec.
Step 2: 64000 / 20 = 3200 bps = 3.125 Kbps (wait, text: 6.25? Recalc: 10*1600*8=128000 bits/20=6400 bps=6.25 Kbps).
Step 3: Higher for video.
Simple Way: Bits per time.

Example 4: EM Spectrum (Fig 11.12)

Simple Explanation: Freq divisions (Degree: Ranges, Cardinality: 4 types).

Wave	Range	Use
Radio	3KHz-1GHz	FM
Micro	1-300GHz	Satellite
Infrared	300GHz-400THz	Remote
Light	400-900THz	Visible

Step 1: Plot freq.
Step 2: Assign properties.
Step 3: Wireless selection.
Simple Way: Higher freq shorter range.

Example 5: Mobile Generations

Simple Explanation: Evolution table (2025: 5G focus).

Gen	Year	Key Feature
1G	1982	Analog voice
2G	1991	Digital/SMS
3G	2001	Data access
4G	2010s	Multimedia
5G	2020s	Gbps/IoT

Step 1: Analog to digital.
Step 2: Add services (SMS to IoT).
Step 3: Speed increase.
Simple Way: G = Generation advance.

Example 6: Protocols Comparison

Simple Explanation: Client-server examples.

Protocol	Use	Model
HTTP	Web	Request-response
FTP	Files	Client-server
PPP	Direct link	Auth
SMTP	Email send	Queue
TCP/IP	Packets	Routing

Step 1: Define purpose.
Step 2: Handle issues (formats).
Step 3: Ensure delivery.
Simple Way: Rules for harmony.

Tip: Sketch figs; troubleshoot (e.g., low bandwidth slow). Added for waves, generations.

Quick Revision Notes & Mnemonics

Concise, easy-to-learn summaries for all subtopics. Structured in tables for quick scan: Key points, examples, mnemonics. Covers components, media, protocols. Bold key terms; short phrases for fast reading.

Subtopic	Key Points	Examples	Mnemonics/Tips
Components	5 Cs: Sender/Receiver/Message/Media/Protocols. Nodes in network.	Fig 11.2 flow.	SRMMP (Sender Receiver Message Media Protocols). Tip: "Send Right Message My Protocol" – Exchange chain.
Capacity	BW: Freq range (Hz). Rate: bps (K/M/G/T). Ex 11.1 calc.	1 Mbps=10^6 bps.	BDR (Bandwidth Data Rate). Tip: "Big Bandwidth = Big Data Rate" – Speed formula.
Types	SHF: Simplex/Half/Full-duplex. One/two-way.	Phone full-duplex.	SHF (Simplex Half Full). Tip: "Simple Half Full Like Roads" – Directions.
Switching	CP: Circuit (dedicated)/Packet (break). Temp routes.	VoIP packet.	CP (Circuit Packet). Tip: "Circuit Permanent, Packet Pieces" – Path vs parts.
Media	Wired: Twisted/Coax/Fiber. Wireless: Radio/Micro/IR (Table 11.1).	WiFi radio.	TCF-RMI (Twisted Coax Fiber Radio Micro IR). Tip: "Wired Tough, Wireless Roams" – Guided vs unguided.
Technologies	BT/WiFi: Short/local wireless. APs/piconet.	Bluetooth 10m.	BW (Bluetooth WiFi). Tip: "Blue Tooth Wireless Fidelity" – Short range.
Mobile Gens	1-5G: Voice to IoT. Speed increase.	5G Gbps.	12345 (Gens). Tip: "1 Analog, 2 Digital, 3 Data, 4 Fast, 5 IoT" – Evolution.
Protocols	HFPS T: HTTP/FTP/PPP/SMTP/TCPIP. Flow/access.	HTTP web.	HFPS T (HTTP FTP PPP SMTP TCP/IP). Tip: "Happy Feet Play Soccer Today" – Rules set.

Overall Tip: Use SRMMP-BDR-SHF-CP-TCF-RMI-BW-12345-HFPS T for full scan (5 mins). Flashcards: Front (term), Back (points + mnemonic). Print table for wall revision. Covers 100% chapter – easy for exams!

Key Terms & Processes - All Key

Expanded table 30+ rows; quick ref. Added advanced (e.g., VoIP, OSI).

Term/Process	Description	Example	Usage
Data Communication	Device data exchange	PC-printer	Network
Sender	Data originator	Computer	Transmit
Receiver	Data destination	Printer	Receive
Message	Exchanged info	Video	Content
Transmission Media	Signal path	Cable	Carry
Protocol	Rules set	HTTP	Reliability
Bandwidth	Freq range	1 MHz	Capacity
Data Rate	Bits/sec	1 Mbps	Speed
Simplex	One-way	Keyboard	Unidirect
Half-Duplex	Alternate two-way	Walkie	Shared
Full-Duplex	Simultaneous two-way	Phone	Bidirect
Circuit Switching	Dedicated path	Old call	Continuous
Packet Switching	Packet routes	Internet	Efficient
Twisted Pair	Twisted copper	LAN	Cheap
Coaxial	Shielded core	TV	Interference low
Fiber Optic	Light cable	Backbone	High speed
Radio Waves	Omni EM	FM	Long range
Microwaves	Uni EM	Satellite	Line-sight
Infrared	Short EM	Remote	Point-point
Bluetooth	Short wireless	Headphones	Piconet
WiFi	Wireless LAN	Home net	APs
1G	Analog voice	1982 calls	Basic
2G	Digital SMS	1991	Security
3G	Data voice	2001 internet	Capacity
4G	Multimedia	Video	Fast
5G	Gbps IoT	Vehicles	M2M
HTTP	Web protocol	URL	Browse
FTP	File transfer	Download	Share
PPP	Direct auth	Modem	Link
SMTP	Email send	Queue	Delivery
TCP/IP	Packet rules	Routing	Internet
VoIP (Adv)	Voice over IP	Zoom	Packet voice
EM Spectrum (Adv)	Wave ranges	3KHz-900THz	Wireless
Line-of-Sight (Adv)	Direct path	Micro	Propagation
Piconet (Adv)	BT network	Master-slave	Short
Access Point (Adv)	WiFi hub	Router connect	WLAN
M2M (Adv)	Machine-machine	IoT	5G

Tip: Examples memory; sort subtopic. Easy: Table scan. Added 10 rows depth.

Communication Processes Step-by-Step

Step-by-step breakdowns of core processes, structured as full questions followed by detailed answers with steps. Visual descriptions for easy understanding; focus on actionable Q&A with examples from chapter.

Question 1: How does data flow in components (Fig 11.2)?

Answer:

Step 1: Sender encodes message.
Step 2: Protocols format/check.
Step 3: Media carries signals.
Step 4: Receiver decodes.
Step 5: Acknowledge if needed.
Step 6: Ensure reliability.

Visual: Arrow flow – Sender → Protocols → Media → Receiver. Example: Email send.

Question 2: Calculate data rate for a channel (Ex 11.1 variation).

Answer:

Step 1: Bits total = pages * chars * bits/char.
Step 2: Time in sec.
Step 3: Rate = total bits / time.
Step 4: Convert to Kbps ( /1024).
Step 5: Rel to bandwidth.
Step 6: Higher for media.

Visual: Formula box – (P*C*B)/T. Example: 10pg/20s = 6.25 Kbps.

Question 3: Packet switching process (detailed).

Answer:

Step 1: Break message into packets.
Step 2: Add header (addr/info).
Step 3: Transmit independently (diff routes).
Step 4: Reach destination.
Step 5: Reassemble in order.
Step 6: Free channel.

Visual: Message → Packets (arrows diff paths) → Reassemble. Example: VoIP call.

Question 4: Wireless signal propagation (microwaves).

Answer:

Step 1: Emit from antenna.
Step 2: Line-of-sight align.
Step 3: Travel uni-directional.
Step 4: Weaken over dist.
Step 5: Repeater regenerate.
Step 6: Receive/decode.

Visual: Dish antennas facing – Signal fade → Repeater boost. Example: Satellite link.

Question 5: HTTP request-response (Fig implied).

Answer:

Step 1: User enters URL.
Step 2: Browser (client) sends HTTP request.
Step 3: Server processes.
Step 4: Response with page.
Step 5: Display in browser.
Step 6: TCP ensures delivery.

Visual: Client → Request → Server → Response → Client. Example: ncert.nic.in load.

Question 6: Bluetooth pairing process.

Answer:

Step 1: Devices in range (10m).
Step 2: Master initiates connect.
Step 3: Slave accepts (auth if needed).
Step 4: Form piconet.
Step 5: Communicate (up to 7 active).
Step 6: Disconnect free.

Visual: Master hub → Slaves spokes. Example: Phone to headphones.

Tip: Treat as FAQ; apply to figs. Easy: Q → Steps + Visual. Full Q&A for exam-like practice.

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