Computer Science for IGCSE & O level - Data Transmission (Section 1)
1
What is the function of the 'trailer' in a data packet?
คำตอบ(C)
To detect transmission errors.
2
Which technique does a checksum employ to detect errors in data transmission?
คำตอบ(B)
Calculating a numerical value and comparing it at the receiver.
3
What type of data transmission is best suited for an internet connection?
4
Which of the following is a key characteristic of quantum cryptography?
คำตอบ(A)
Relies on the principles of quantum mechanics.
5
Which of the following methods uses an extra bit added to a byte to ensure an even number of 1s or an odd number of 1s?
6
What does 'hop number' control in a packet-switched network?
7
What is "plaintext" in the context of cryptography?
คำตอบ(B)
The original, unencrypted message
8
In asymmetric encryption, who should keep the private key secret?
9
What does the 'sequence number' in a packet's header ensure?
คำตอบ(A)
The order of transmission of the packets
10
What is the purpose of a 'router' in a network?
11
Which is a characteristic of serial data transmission?
คำตอบ(B)
Suitable for long distances.
12
What is the main purpose of 'hashing' in data security?
คำตอบ(B)
To create a unique fingerprint of data for integrity verification.
13
What is the function of the 'data link layer' in the OSI model?
คำตอบ(A)
Providing reliable node-to-node data transfer.
14
In the context of packet switching, what is the role of a 'router'?
คำตอบ(C)
To determine the best path for each packet.
15
In the ISBN-13 calculation, what is the weight assigned to the first digit?
16
Which error-detection method is based on calculating a value using all bits in the payload?
17
What is the defining characteristic of 'Simplex' data transmission?
คำตอบ(A)
Data transmission in one direction only.
18
What is the purpose of the 'trailer' in a data packet?
คำตอบ(C)
To help detect transmission errors.
19
In an ARQ system, what does a 'negative acknowledgement' (NAK) indicate?
คำตอบ(C)
The receiver has detected an error in the received data.
20
What is the purpose of a 'proxy server'?
คำตอบ(C)
To filter network traffic and provide caching.
21
What are the potential drawbacks of using the USB system?
22
If a single bit error occurs in a data transmission using an even parity scheme, how will it be detected?
23
What does the 'payload' in a data packet contain?
คำตอบ(C)
The actual data being transmitted
24
Which method helps to prevent packets from circulating endlessly in a network?
25
What is a primary advantage of packet switching?
คำตอบ(C)
Allows multiple users to share network resources efficiently.
26
In the context of data transmission, what is a 'packet'?
คำตอบ(B)
A formatted unit of data transmitted over a network.
27
What is the main characteristic of parallel data transmission?
คำตอบ(B)
Data is transmitted multiple bits at a time over several channels.
28
Which of the following is a function of the 'network layer' in the OSI model?
คำตอบ(B)
Routing data packets between networks.
29
What is the main difference between Simplex and Half-duplex data transmission modes?
คำตอบ(B)
Simplex transmits data in one direction only, while half-duplex transmits in both directions, but not simultaneously.
30
คำตอบ(A)
A network of compromised computers controlled by a single attacker.
31
What is the main function of an Automatic Repeat Request (ARQ)?
คำตอบ(B)
To detect and correct errors that occur during transmission.
32
What is the main advantage of using fiber optic cables for data transmission?
คำตอบ(B)
Resistance to electrical interference.
33
What best describes the function of an 'Intrusion Detection System (IDS)'?
คำตอบ(B)
To detect malicious activity and log security events.
34
What is a disadvantage of echo checks?
คำตอบ(B)
It takes more time to send and receive the data.
35
Which of the following is/are advantage(s) of using USB connection?
36
What would cause a "time-out" in ARQ?
คำตอบ(D)
No acknowledgment received within a given period.
37
Which of the following is a main difference between Symmetric and Asymmetric Encryption?
คำตอบ(B)
Symmetric uses same key for encryption and decryption while Asymmetric uses two different keys.
38
What is the role of a 'gateway' in a network?
คำตอบ(B)
To act as the entry point to another network.
39
What happens if the receiver detects an error using a checksum?
คำตอบ(C)
A retransmission is requested.
40
Which of the following are examples of wireless network technologies?
41
What is the purpose of a 'MAC address'?
คำตอบ(A)
To identify a device on a network.
42
What type of error is detectable by a check digit?
43
What does the term 'payload' refer to in data transmission?
คำตอบ(B)
The actual data being transmitted.
44
In an ARQ system, what happens if the sender does not receive an acknowledgment (ACK) within a specific time limit?
คำตอบ(B)
The sender resends the data.
45
What type of checking method is used to make sure that the packets which reaches the destination are complete?
คำตอบ(C)
Cyclic Redundancy Checks (CRCs)
46
In the context of a network, what action does a router primarily perform?
คำตอบ(C)
Forwarding data packets based on their destination address.
47
What does the term 'full-duplex' refer to in data transmission?
คำตอบ(A)
The ability to send and receive data simultaneously.
48
What are the main functions of the data link layer?
49
What is the role of a router in a packet-switched network?
คำตอบ(C)
To determine the best path for a packet.
50
Which of the following is a method for determining data integrity?
