Science & Technology
Computers and Information Technology
Internet, Telecommunication and Cyber Security
Networks, optical fibre, internet history and protocols, IP addresses, 1G to 5G, cyber threats, CERT-In, the IT Act 2000, DPDP Act 2023 and the Telecom Act 2023.
Prerequisites
- Computer Basics: bits, bytes and binary, since every message travels as 0s and 1s.
- Physics in Everyday Life: electromagnetic waves and total internal reflection explain radio, mobile signals and optical fibre.
The Hook: A Mobile Tower in an Interior Bastar Village
Connect
For years, people in many villages of the Bastar division walked to a hilltop to catch one bar of mobile signal. When a new tower comes up and an optical fibre line reaches the block headquarters, life changes within months: a student downloads a CGPSC syllabus, a forest-produce collector receives payment on UPI, a health worker sends a patient’s report to a doctor in Jagdalpur.
What actually carries that payment from a phone in the forest to a bank server hundreds of kilometres away? How did “the internet” begin, why is 5G different from 4G, and who protects users when a fraudster calls pretending to be a police officer? This page answers those questions.
Why it matters: Prelims tests abbreviations, protocols, “first/inventor” facts and laws (IT Act sections, DPDP Act). The CGPSC Mains GS-II syllabus explicitly lists IT and computers in communication and in rural India, so you need both the technology and its social effects.
Communication Basics (संचार)
Every communication system has a transmitter → channel (medium) → receiver, with noise disturbing the signal on the way.
| Term | Meaning |
|---|---|
| Analog signal | Continuous wave (old landline voice, AM/FM radio) |
| Digital signal | Discrete 0s and 1s; less affected by noise, easy to encrypt and compress |
| Modulation | Loading the message onto a high-frequency carrier wave: AM (amplitude), FM (frequency, less noise, better music quality), and digital forms |
| Modem | Modulator-demodulator: converts digital data to signals for the line and back |
| Bandwidth | Range of frequencies a channel can carry; for data, the maximum rate (bits per second) |
| Latency | Delay before data starts arriving; low latency matters for video calls, remote surgery, self-driving vehicles |
Transmission modes:
| Mode | Direction | Example |
|---|---|---|
| Simplex | One way only | Radio and TV broadcast |
| Half-duplex | Both ways, but one at a time | Walkie-talkie |
| Full-duplex | Both ways at the same time | Telephone call |
Transmission media
| Guided (wired) | Unguided (wireless) |
|---|---|
| Twisted pair (telephone lines, LAN cables) | Radio waves (FM, mobile phones) |
| Coaxial cable (cable TV) | Microwaves (towers in line of sight, satellite links) |
| Optical fibre: light pulses guided by total internal reflection; huge bandwidth, very low loss, immune to electrical interference | Infrared (TV remote, very short range) |
| Satellite (geostationary satellites about 35,786 km above the equator, used for TV, VSAT and remote connectivity) |
Why optical fibre is the backbone
A hair-thin glass fibre carries far more data than copper, over longer distances, without picking up electrical noise. Charles K. Kao received the 2009 Nobel Prize in Physics for showing how light could be sent through fibre over long distances. BharatNet, India’s rural broadband programme, is essentially a project to lay optical fibre to every gram panchayat.
Computer Networks
| Type | Area covered | Example |
|---|---|---|
| PAN | A few metres | Phone connected to earbuds via Bluetooth |
| LAN | A building or campus | A college computer lab |
| MAN | A city | City-wide cable or Wi-Fi network |
| WAN | Countries, the world | The internet is the largest WAN |
Topologies: bus (one cable, cheap, one break stops all), star (all nodes to a central hub or switch, the most common in LANs), ring, mesh (every node linked to many others, very reliable) and tree.
| Device | Job |
|---|---|
| Hub | Repeats incoming data to every port (unintelligent) |
| Switch | Sends data only to the intended device inside a LAN |
| Router | Connects different networks and picks the best path for data packets (home Wi-Fi router connects your LAN to the internet) |
| Repeater | Boosts a weakening signal over long distances |
| Gateway | Joins networks that use different protocols |
The Internet (इंटरनेट)
Timeline
timeline
title From ARPANET to the Indian internet
1969 : ARPANET, a US Defense Department network, links its first computers
1983 : ARPANET switches to TCP/IP (1 January), the birth of the modern internet
1986 : ERNET links Indian educational and research institutions
1989 : Tim Berners-Lee proposes the World Wide Web at CERN
1995 : VSNL launches public internet service in India (15 August)- TCP/IP was designed by Vint Cerf and Bob Kahn, often called the “fathers of the internet”.
- Tim Berners-Lee created the World Wide Web: HTML, HTTP, URLs and the first web browser and server.
Internet is not the same as the Web
The internet is the global network of networks (the roads). The World Wide Web is one service running on it: linked web pages (the vehicles on one kind of road). Email, UPI transactions, video calls and file transfers use the internet without being “the Web”.
Protocols (rules of communication)
| Protocol | Use |
|---|---|
| TCP/IP | Core suite: IP addresses and routes packets; TCP checks every packet arrives in order |
| HTTP / HTTPS | Web pages; HTTPS adds encryption (TLS), shown by the padlock in the browser |
| FTP | File transfer |
| SMTP | Sending email |
| POP3 / IMAP | Receiving email (IMAP keeps mail synced on the server) |
| DNS | Translates names like cgstate.gov.in into IP addresses: the internet’s “phone book” |
| DHCP | Automatically gives a device an IP address when it joins a network |
| VoIP | Voice calls over the internet (WhatsApp calls) |
Addresses and names
| Item | Key fact |
|---|---|
| IPv4 | 32-bit address, about 4.3 billion addresses, written like 192.168.1.1; nearly exhausted |
| IPv6 | 128-bit address, practically unlimited; needed for billions of IoT devices |
| MAC address | Permanent hardware address of a network card (48-bit) |
| URL | Full web address: protocol + domain + path, e.g. https://www.india.gov.in/ |
| Domain names | Top-level domains: .gov.in, .nic.in, .com, .org; India’s country code is .in |
| ICANN | Global body coordinating domain names and IP address allocation |
Other terms: browser (Chrome, Firefox) vs search engine (Google, Bing); cookies (small files a site stores to remember you); intranet (private network inside an organisation) vs extranet (intranet opened to selected outsiders); dark web (hidden sites needing special software).
Short-range wireless
| Technology | Range / feature | Example |
|---|---|---|
| Wi-Fi | Wireless LAN (IEEE 802.11 standards) | Home broadband, public Wi-Fi hotspots |
| Bluetooth | Short range, low power | Earbuds, smartwatch |
| NFC | A few centimetres | Tap-to-pay cards and phones |
| RFID | Radio tags read without line of sight | FASTag, library books, livestock tags |
| Li-Fi | Data carried by visible light from LED bulbs | Experimental, interference-free zones |
Mobile Telephony: 1G to 6G
| Generation | Key feature | India milestone |
|---|---|---|
| 1G | Analog voice only | Not widely deployed in India |
| 2G | Digital voice, SMS; GSM and CDMA | India’s first mobile call: 31 July 1995, Kolkata to Delhi |
| 3G | Mobile internet, video calls | Rolled out from the late 2000s |
| 4G | All-IP broadband (LTE), HD video streaming | 2010s; the cheap-data boom of the late 2010s pushed rural internet use sharply up |
| 5G | Very high speed, ultra-low latency, massive device connections, network slicing | Launched 1 October 2022 at the India Mobile Congress |
| 6G | Expected around 2030: terahertz frequencies, AI-native networks | Bharat 6G Vision document (March 2023) |
Why 5G matters for rural India
5G’s low latency and capacity enable telemedicine and remote diagnostics, precision farming with sensors and drones, smart grids, and better connectivity at crowded places. The challenge is cost: 5G needs dense towers and fibre backhaul, so rural coverage depends on BharatNet and on funding from the Digital Bharat Nidhi.
Satellite communication: India’s INSAT and GSAT series (ISRO) carry TV, DTH, VSAT banking links, disaster communication and connectivity for islands and remote hills. DD Free Dish gives free-to-air TV through satellite to households beyond cable networks. See Space and Defence Technology.
Cyber Security (साइबर सुरक्षा)
Threats
| Threat | What it is |
|---|---|
| Virus | Malicious code that attaches to a file and spreads when that file runs |
| Worm | Self-replicating malware that spreads through networks on its own |
| Trojan horse | Looks like useful software but hides malicious code |
| Ransomware | Encrypts the victim’s data and demands payment (the WannaCry attack of 2017 hit computers worldwide) |
| Spyware / keylogger | Secretly records activity or keystrokes (passwords) |
| Phishing | Fake emails or websites that trick users into giving passwords or OTPs. Variants: vishing (voice calls), smishing (SMS) |
| DoS / DDoS | Flooding a server with traffic so genuine users cannot reach it |
| SIM swap | Fraudster gets a duplicate SIM to receive your OTPs |
| “Digital arrest” scam | Fraudsters on video calls pose as police or investigators and frighten victims into transferring money. No Indian law provides for arrest over a video call |
| Deepfake | AI-generated fake video or audio of a real person |
Defences
- Firewall (filters traffic between networks), antivirus, regular software updates.
- Encryption: symmetric (one shared key) and asymmetric or public-key (a public key to lock, a private key to unlock; the basis of digital signatures and HTTPS).
- Two-factor authentication (password + OTP or biometric); never share OTPs.
- Report: national cybercrime helpline 1930 and the portal cybercrime.gov.in.
Institutions
| Body | Role |
|---|---|
| CERT-In (Indian Computer Emergency Response Team), under MeitY | National agency for responding to cyber incidents (operational since 2004; statutory role under Section 70B of the IT Act) |
| NCIIPC (under NTRO) | Protects critical information infrastructure such as power grids, banking and telecom (Section 70A) |
| I4C (Indian Cyber Crime Coordination Centre), under the Ministry of Home Affairs | Coordinates action against cybercrime; runs the 1930 helpline and the reporting portal |
Laws on IT and Communication
| Law | Key points |
|---|---|
| Information Technology Act, 2000 | India’s first cyber law, based on the UNCITRAL Model Law on Electronic Commerce (1996). Gives legal recognition to electronic records and digital signatures, defines cyber offences, and set up the Controller of Certifying Authorities |
| IT (Amendment) Act, 2008 | Added offences such as identity theft (66C), cheating by personation (66D), violation of privacy (66E) and cyber terrorism (66F); power to block websites (69A); statutory roles for CERT-In and NCIIPC; also inserted Section 66A (offensive messages) |
| Shreya Singhal v. Union of India (2015) | Supreme Court struck down Section 66A as violating free speech under Article 19(1)(a); upheld Section 69A blocking with safeguards |
| K.S. Puttaswamy v. Union of India (2017) | Nine-judge bench: privacy is a Fundamental Right under Article 21. This led to a data protection law |
| Digital Personal Data Protection (DPDP) Act, 2023 | Received assent in August 2023. Consent-based processing of digital personal data; duties of Data Fiduciaries; rights of Data Principals (access, correction, erasure, grievance redressal); Data Protection Board of India to adjudicate breaches and impose penalties. DPDP Rules, 2025 were notified in November 2025, with obligations phased in over about 18 months (as of 2026) |
| Telecommunications Act, 2023 | Replaced the colonial Indian Telegraph Act, 1885 and the Wireless Telegraphy Act, 1933. Renamed the Universal Service Obligation Fund (USOF) as the Digital Bharat Nidhi, whose rules came into force on 31 August 2024 and whose scope now includes research, start-ups and services in under-served areas |
Mains angle: privacy versus digital governance
Digital governance runs on data: Aadhaar, land records, ration cards, health IDs. The DPDP Act tries to balance innovation and service delivery against privacy. Points often raised in debate: broad exemptions for the State, the independence of the Data Protection Board, and the amendment the Act made to the Right to Information Act regarding personal information. A balanced answer notes both the long-awaited protection for citizens and these concerns.
Memory Tricks
Email protocols: 'SMTP Sends, POP Pulls'
SMTP Sends mail out; POP3/IMAP pull it in. IMAP keeps it on the server (In sync Mail Across devices).
IPv4 vs IPv6: 'Four bytes, sixteen bytes'
IPv4 = 4 bytes = 32 bits. IPv6 = 16 bytes = 128 bits.
Internet timeline: 69–83–89–95
1969 ARPANET → 1983 TCP/IP → 1989 Web proposed → 1995 India online (15 August, VSNL).
Don’t Confuse
| This | vs | That |
|---|---|---|
| Internet: network of networks | vs | WWW: linked pages on the internet (Berners-Lee) |
| Switch: within one LAN | vs | Router: between networks |
| Virus: needs a host file | vs | Worm: spreads on its own |
| Phishing: email or fake site | vs | Vishing: voice call; smishing: SMS |
| Section 66A (struck down, 2015) | vs | Section 69A (blocking power, upheld) |
| CERT-In (Sec 70B): incident response | vs | NCIIPC (Sec 70A): critical infrastructure |
| USOF (old name) | vs | Digital Bharat Nidhi (Telecom Act, 2023) |
| Browser (Chrome) | vs | Search engine (Google Search) |
Common Mistakes
MCQ traps
- “Tim Berners-Lee invented the internet.” False. He created the World Wide Web (1989); the internet’s TCP/IP base came from Cerf and Kahn.
- “Optical fibre works on refraction alone.” The key principle is total internal reflection.
- “IPv6 uses 64-bit addresses.” False. IPv6 is 128-bit; IPv4 is 32-bit.
- “SMTP is used to receive email.” False. SMTP sends; POP3 and IMAP receive.
- “Section 66A of the IT Act is still in force.” False. It was struck down in Shreya Singhal (2015).
- “The DPDP Act covers all personal data, including paper records.” It covers digital personal data, and non-digital data once it is digitised.
Practice
All questions below are original practice questions written in CGPSC style. They are not previous-year questions.
Level 1: Foundation
- The principle that keeps light inside an optical fibre is ______.
- The protocol that translates domain names into IP addresses is ______.
- 5G services were launched in India on ______.
- The Supreme Court struck down Section 66A of the IT Act in the case ______.
Answers
- Total internal reflection.
- DNS (Domain Name System).
- 1 October 2022.
- Shreya Singhal v. Union of India (2015).
Level 2: Prelims MCQs
Q1. Consider the following statements:
- IPv6 addresses are 128 bits long, compared with 32 bits for IPv4.
- SMTP is the protocol used for receiving email from a mail server.
- HTTPS encrypts the data exchanged between a browser and a website.
Which of the statements given above is/are correct?
- (a) 1 and 3 only
- (b) 2 only
- (c) 2 and 3 only
- (d) 1, 2 and 3
Answer and explanation
(a) 1 and 3 only. IPv6 is 128-bit and IPv4 32-bit. SMTP sends mail; POP3 and IMAP receive it, so statement 2 is wrong. HTTPS adds TLS encryption to HTTP.
Q2. Match List I (Device) with List II (Function):
| List I | List II |
|---|---|
| A. Router | 1. Converts digital data into signals for a transmission line and back |
| B. Modem | 2. Boosts a weak signal over long distances |
| C. Repeater | 3. Connects networks using different protocols |
| D. Gateway | 4. Forwards data packets between different networks along the best path |
- (a) A-4, B-1, C-3, D-2
- (b) A-4, B-1, C-2, D-3
- (c) A-1, B-4, C-2, D-3
- (d) A-2, B-1, C-4, D-3
Answer and explanation
(b) A-4, B-1, C-2, D-3. Routers choose paths between networks; a modem modulates and demodulates; a repeater regenerates signals; a gateway translates between networks that use different protocols.
Q3. Which one of the following statements about the Telecommunications Act, 2023 is correct?
- (a) It amended the Indian Telegraph Act, 1885 but kept it in force.
- (b) It renamed the Universal Service Obligation Fund as the Digital Bharat Nidhi.
- (c) It set up the Data Protection Board of India.
- (d) It struck down Section 66A of the IT Act.
Answer and explanation
(b). The 2023 Act replaced the Telegraph Act, 1885 (so (a) is wrong) and renamed USOF as the Digital Bharat Nidhi. The Data Protection Board comes from the DPDP Act, 2023. Section 66A was struck down by the Supreme Court in 2015, not by any Act.
Q4. A malicious program spreads across a computer network by copying itself, without needing to attach to any file or be opened by a user. It is best described as a:
- (a) Trojan horse
- (b) Virus
- (c) Worm
- (d) Spyware
Answer and explanation
(c) Worm. A virus needs a host file and user action; a Trojan disguises itself as useful software; spyware secretly monitors. Worms are self-replicating across networks.
Q5. With reference to the history of the internet, which of the following pairs is correctly matched?
- (a) ARPANET : developed by CERN
- (b) World Wide Web : Tim Berners-Lee
- (c) Public internet in India : launched by BSNL in 2000
- (d) TCP/IP : invented by Charles Kao
Answer and explanation
(b). ARPANET was a US Defense Department project (1969); the Web came out of CERN. Public internet in India was launched by VSNL on 15 August 1995. TCP/IP is credited to Vint Cerf and Bob Kahn; Charles Kao is known for optical fibre.
Level 3: Mains Answer Writing
Q1. (60 words) Why is optical fibre preferred over copper cable for long-distance communication?
Model answer outline
- Principle: light pulses guided by total internal reflection.
- Advantages: far higher bandwidth; very low signal loss, so fewer repeaters; immune to electromagnetic interference; hard to tap, so more secure; light and thin; glass made from silica is abundant.
- Use: backbone of the internet and of BharatNet’s rural broadband.
Q2. (150–200 words) Rising internet use has brought a rise in cyber fraud in rural India. Examine the causes and suggest measures, with reference to the legal framework.
Model answer outline
- Intro: cheap smartphones, cheap data and UPI brought millions of first-time users online; fraudsters target their unfamiliarity.
- Causes: low digital literacy; OTP and KYC-update scams; fake loan apps; SIM swaps; “digital arrest” calls; sharing of phones within households; reporting reluctance; under-equipped local police.
- Legal and institutional framework: IT Act, 2000 (66C identity theft, 66D cheating by personation); DPDP Act, 2023 for data misuse; CERT-In; I4C with the 1930 helpline and cybercrime.gov.in; RBI and NPCI fraud-limit rules.
- Measures: digital literacy through CSCs and self-help groups; awareness in Hindi, Chhattisgarhi and tribal languages; quick freezing of fraud transactions through the 1930 helpline; cyber cells and trained police in every district; bank-level alerts and limits for new users.
- Chhattisgarh angle: first-time smartphone users, including women who received phones under the state’s Sanchar Kranti Yojana (2018), show why digital access must come with digital safety.
- Conclusion: digital inclusion is incomplete without digital safety; awareness, quick redressal and strong enforcement must grow with connectivity.
Quick Revision Table
| Fact | Detail |
|---|---|
| ARPANET | 1969, US Defense Department |
| TCP/IP adopted | 1 January 1983 (Vint Cerf, Bob Kahn) |
| World Wide Web | Tim Berners-Lee, CERN, 1989 |
| Internet in India | VSNL, 15 August 1995; ERNET (1986) for research and education |
| First mobile call in India | 31 July 1995, Kolkata to Delhi |
| 5G launch | 1 October 2022 (India Mobile Congress) |
| Bharat 6G Vision | March 2023 |
| IPv4 / IPv6 | 32-bit / 128-bit |
| SMTP / POP3, IMAP | Send / receive mail |
| DNS | Names to IP addresses |
| Optical fibre | Total internal reflection; Charles Kao, Nobel 2009 |
| Geostationary orbit | About 35,786 km above the equator |
| IT Act | 2000; amended 2008; based on UNCITRAL Model Law |
| Section 66A | Struck down, Shreya Singhal (2015) |
| CERT-In / NCIIPC | Sec 70B / Sec 70A |
| Privacy | Fundamental Right, Puttaswamy (2017) |
| DPDP Act | 2023; Rules notified November 2025; Data Protection Board |
| Telecom Act 2023 | Replaced Telegraph Act 1885; USOF → Digital Bharat Nidhi |
| Cyber fraud helpline | 1930; cybercrime.gov.in |
Key Takeaways
Key Takeaways
- Communication = transmitter, channel, receiver; optical fibre (total internal reflection) is the backbone and wireless carries the last mile.
- The internet (TCP/IP, 1983) is not the Web (Berners-Lee, 1989); India went online on 15 August 1995.
- Each mobile generation added a capability: digital voice (2G), data (3G), broadband (4G), low latency and massive connectivity (5G, India 2022).
- Know the threat types and the defenders: CERT-In (70B), NCIIPC (70A), I4C and the 1930 helpline.
- The legal frame is the IT Act 2000 (66A struck down in 2015), the DPDP Act 2023 (rules November 2025) and the Telecommunications Act 2023 (Digital Bharat Nidhi).
What’s Next
- Digital India, E-Governance and IT in Rural India: how this network delivers services to villages
- IT and E-Governance in Chhattisgarh: Bastar Net, CHOiCE, the PDS model
- Fundamental Rights: Article 19(1)(a) and Article 21, the constitutional roots of Shreya Singhal and Puttaswamy
- Money, Banking and Inflation: UPI and digital payments from the economy side
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