Paper 1: Data Transmission

Question 1

Serial Data Transmission

Answer 1

Data is sent one bit at a time over a single wire. Useful for long distances where fewer wires are preferred (e.g., USB).

Question 2

Parallel Data Transmission

Answer 2

Multiple bits of data are sent simultaneously over several parallel wires. Generally faster for short distances (e.g., within a computer).

Question 3

Simplex Transmission

Answer 3

Data transmission in only one direction (e.g., a radio broadcast).

Question 4

Half-Duplex Transmission

Answer 4

Data transmission in both directions, but only one direction at a time (e.g., a walkie-talkie).

Question 5

Full-Duplex Transmission

Answer 5

Data transmission in both directions simultaneously (e.g., a phone call).

Question 6

Packet Switching

Answer 6

A method of transmitting data by dividing it into small units called packets, which are then sent independently over a network and reassembled at the destination. Makes efficient use of network resources.

Question 7

Parity Check

Answer 7

A simple method of error detection where an extra bit (parity bit) is added to a group of bits to indicate whether the number of 1s is even or odd.

Question 8

Check Digit

Answer 8

An extra digit added to a code (like an ISBN or barcode) to help detect errors during data entry or transmission.

Question 9

Encryption

Answer 9

The process of converting data into a secret code (ciphertext) to prevent unauthorized access.

Question 10

Symmetric Encryption

Answer 10

An encryption method that uses the same key for both encrypting and decrypting data.

Question 11

Asymmetric Encryption

Answer 11

An encryption method that uses two different keys: a public key for encryption and a private key for decryption. The public key can be shared, but the private key must be kept secret.

Question 12

Internet

Answer 12

A global network of interconnected computer networks that use the Internet Protocol Suite (TCP/IP) to communicate.

Question 13

World Wide Web (WWW)

Answer 13

A system of interlinked hypertext documents (web pages) accessed via the Internet. It’s one of the services that runs on the Internet.

Question 14

URL (Uniform Resource Locator)

Answer 14

The address of a resource on the internet (like a web page). It tells the browser how and where to find the resource.

Question 15

HTTP (Hypertext Transfer Protocol)

Answer 15

The protocol used for transferring files (like web pages, images, etc.) on the World Wide Web.

Question 16

HTTPS (Hypertext Transfer Protocol Secure)

Answer 16

A secure version of HTTP that encrypts the communication between the web browser and the web server, protecting sensitive data.

Question 17

HTML (Hypertext Markup Language)

Answer 17

The standard markup language for creating web pages. It defines the structure and content of a web page.

Question 18

CSS (Cascading Style Sheets)

Answer 18

A style sheet language used for describing the look and formatting of a document written in HTML. It controls the visual presentation of a web page.

Question 19

IP Address (Internet Protocol Address)

Answer 19

A unique numerical label assigned to each device connected to a computer network that uses the Internet Protocol for communication.

Question 20

MAC Address (Media Access Control Address)

Answer 20

A unique hardware address assigned to a network interface controller (NIC) of a device. It’s used for communication within a local network.

Question 21

Cookie (Internet)

Answer 21

A small piece of data sent from a website and stored on the user’s computer by the web browser. It can be used to remember information about the user or their browsing activity.

Question 22

Malware

Answer 22

Software that is intended to damage or disable computers and computer systems. Examples include viruses, worms, and spyware.

Question 23

Phishing

Answer 23

A type of online fraud where criminals try to trick you into giving them personal information (like passwords or credit card details) by pretending to be a legitimate organization.

Question 24

Denial-of-Service (DoS) Attack

Answer 24

An attack that aims to make a computer resource unavailable to its intended users, often by overwhelming it with traffic.

Question 25

Firewall (Software/Hardware)

Answer 25

A security system that monitors and controls incoming and outgoing network traffic based on pre-defined security rules. It acts as a barrier between a trusted internal network and an untrusted external network (like the internet).

Question 26

Antivirus Software

Answer 26

Software designed to detect, prevent, and remove malware from a computer system.

Question 27

Password

Answer 27

A secret sequence of characters used to verify the identity of a user and grant access to a system or resource.

Question 28

Authentication (Methods)

Answer 28

The process of verifying the identity of a user. Examples include passwords, PINs, biometric scans (fingerprint, facial recognition), and two-step verification (using two different methods).

Question 29

What is a packet in data transmission?

Answer 29

A small unit of data that is transmitted over a network. The original data is broken down into these smaller pieces.

Question 30

What information is typically included in a packet?

Answer 30

The actual data being sent (the payload), the sender's address, the receiver's address, and sequence numbers.

Question 31

What are the advantages of using packets for data transmission?

Answer 31

More efficient use of network bandwidth, improved reliability (if one packet is lost, only that packet needs to be retransmitted), and allows for different routes to be taken.

Question 32

Name some common serial data transmission methods.

Answer 32

Simplex, half-duplex, and full-duplex.

Question 33

What are the advantages and disadvantages of serial transmission compared to parallel transmission?

Answer 33

Serial: Advantage - fewer wires needed, less cost, longer distances. Disadvantage - slower for transmitting multiple bits at once. Parallel: Advantage - faster for transmitting multiple bits at once. Disadvantage - more wires needed, higher cost, shorter distances due to signal interference.

Question 34

What does USB stand for?

Answer 34

Universal Serial Bus.

Question 35

What is the purpose of USB?

Answer 35

To provide a standardized interface for connecting various peripheral devices (e.g., keyboards, mice, printers, external drives) to a computer.

Question 36

What are some advantages of using USB?

Answer 36

Plug and play capability (devices are automatically detected), supports multiple data transfer rates, can provide power to some devices.

Question 37

What is the goal of error detection methods?

Answer 37

To identify if errors have occurred during transmission so that corrective action can be taken (e.g., retransmission).

Question 38

What are the limitations of a parity check?

Answer 38

It can only detect an odd number of errors within a data block. If an even number of errors occur, the parity will still appear correct, and the errors will go undetected.

Question 39

Describe how a checksum works for error detection.

Answer 39

A numerical value is calculated from the data being sent. This checksum is transmitted along with the data. The receiver performs the same calculation on the received data and compares the result with the received checksum. If they don't match, an error is detected.

Question 40

Describe how the echo method works for error detection.

Answer 40

The receiver sends the received data back to the sender. The sender then compares the echoed data with the original data. If they are different, an error has occurred.

Question 41

What is a disadvantage of the echo method?

Answer 41

It requires transmission in both directions and can introduce delays.

Question 42

How is a check digit typically used?

Answer 42

An algorithm is applied to the original digits to calculate the check digit. When the number is entered or received, the same algorithm is applied, and the result is compared to the check digit. If they don't match, an error is likely.

Question 43

What does ISBN stand for?

Answer 43

International Standard Book Number.

Question 44

What does ARQ stand for in data transmission?

Answer 44

Automatic Repeat Request.

Question 45

What is the purpose of ARQ?

Answer 45

It's a group of protocols used for error control in data transmission. If an error is detected, ARQ mechanisms automatically request the retransmission of the data that was received in error.

Question 46

Name some basic ARQ protocols.

Answer 46

Stop-and-wait ARQ, Go-Back-N ARQ, and Selective Repeat ARQ.

Question 47

Why is there a need for encryption in data transmission?

Answer 47

To protect the confidentiality and security of data being transmitted, especially over public networks like the internet. It prevents unauthorized access and ensures that only the intended recipient can understand the information.

Question 48

What is the basic principle of encryption?

Answer 48

Converting data (plaintext) into an unreadable format (ciphertext) using an algorithm and a key. The ciphertext can only be converted back to plaintext using the correct key.

Question 49

What is a key challenge with symmetric encryption?

Answer 49

Securely sharing the secret key between the sender and the receiver.

Question 50

What are some advantages of symmetric encryption?

Answer 50

Generally faster and less computationally intensive than asymmetric encryption.

Question 51

How does asymmetric encryption work for secure communication?

Answer 51

The sender encrypts the message using the recipient's public key. Only the recipient's private key can decrypt the message.

Question 52

What are some advantages of asymmetric encryption?

Answer 52

Solves the key distribution problem of symmetric encryption, as the public key can be shared openly.

Question 53

What is a disadvantage of asymmetric encryption?

Answer 53

Generally slower and more computationally intensive than symmetric encryption.