Technical Interview Questions-Electronics & Telecommunication Engineering 2024

Most Commonly Asked Electronics & Telecommunication Engineering -Technical Interview Questions and Answers for freshers 2024.

Question 1: What is your role in the project? (Electronics Project)

Answer: In the project, my role primarily involves designing and implementing the circuitry, ensuring the integration of electronic components, and troubleshooting any issues that may arise. I also collaborate closely with team members to align our efforts and contribute to the overall success of the project.

Question 2: What’s your area of interest? (Engineering – E&TC)

Answer: My area of interest in Electronics and Telecommunications Engineering lies in the design and implementation of communication systems. I am particularly fascinated by signal processing, wireless communication, and the integration of hardware and software in telecommunications.

Question 3: Can you explain the working of each component of your project? (Electronics & Telecommunication Project)

Answer: Certainly. In the project, we have components such as microcontrollers, sensors, amplifiers, and communication modules. The microcontroller processes data from sensors, triggering actions through amplifiers, and communicates the results using designated communication modules. This integration ensures the seamless functioning of the overall system.

Question 4: What are universal gates?

Answer: Universal gates are digital gates that can be used to implement any other type of logic gate. NAND and NOR gates are examples of universal gates. With the proper arrangement, NAND gates or NOR gates alone can be used to perform all the basic logic operations, making them universal building blocks in digital circuit design.

Question 5: Can you explain the OSI model?

Answer: The OSI (Open Systems Interconnection) model is a conceptual framework that standardizes the functions of a telecommunication or computing system into seven abstraction layers. These layers are Physical, Data Link, Network, Transport, Session, Presentation, and Application. Each layer serves specific functions, facilitating interoperability between different systems and enabling a standardized approach to networking and communication protocols.

Read: HR Interview Questions & Answers-Electronics & Telecommunication

Question 6: Can you explain microcontroller processor?

Answer: A microcontroller processor is the central processing unit (CPU) embedded within a microcontroller. It executes instructions stored in memory to control and coordinate the functions of the microcontroller. It plays a pivotal role in processing data, managing input and output, and governing the overall operation of embedded systems.

Question 7: What is the Latest version of C language?

Answer: The most recent publicly available working draft of C23 was released on April 1, 2023. It is expected to be published in 2024. Keep in mind that updates or new versions may have been released since then, so it’s advisable to check for the latest version from authoritative sources.

Question 8: Explain about motors and types of motors?

Answer: Motors are devices that convert electrical energy into mechanical energy. There are various types of motors, including:

DC Motors: Direct current motors, powered by a continuous flow of current.

AC Motors: Alternating current motors, including induction motors and synchronous motors.

Stepper Motors: Used in precise positioning, converting digital input into mechanical movement.

Servo Motors: Controlled by a feedback mechanism, maintaining a specific position or speed.

Question 9: Explain TCP-IP layer?

Answer: TCP/IP (Transmission Control Protocol/Internet Protocol) is a suite of communication protocols. The layers include:

Application Layer: Provides network services directly to end-users.

Transport Layer: Ensures reliable data transfer, with TCP for connection-oriented and UDP for connectionless communication.

Internet Layer: Handles addressing, routing, and fragmentation of data packets.

Link Layer: Manages physical transmission and access to the network medium.

Question 10: Explain functions of the network layer?

Answer: The network layer, also known as the Internet layer in the TCP/IP model, is responsible for logical addressing, routing, and forwarding of data between devices on different networks. It ensures that data packets reach their intended destination by determining the optimal path through interconnected networks. The network layer plays a crucial role in facilitating end-to-end communication across diverse network infrastructures.

Question 11: Can you elaborate on the functions and responsibilities of the transport layer in networking protocols?

Answer: The transport layer, situated in the OSI or TCP/IP model, manages end-to-end communication and ensures reliable data transfer. It uses protocols like TCP for connection-oriented and UDP for connectionless transmission. The transport layer handles error detection, flow control, and data segmentation, contributing to the efficient and secure exchange of information between devices.

Question 12: Could you provide insights into the operational principles of motors?

Answer: Motors are devices converting electrical energy into mechanical energy. Their working involves the interaction of magnetic fields, leading to the generation of rotational motion. In simple terms, when current flows through a coil placed in a magnetic field, a force is exerted, resulting in the rotation of the motor shaft.

Question 13: Can you discuss fundamental concepts related to databases?

Answer: Database concepts encompass the organization, storage, retrieval, and management of data. Key elements include tables for data representation, relationships between tables, normalization for data integrity, SQL for querying and manipulation, and indexing for optimized retrieval. Understanding these concepts is crucial for effective database design and usage.

Question 14: What programming languages are you proficient in?

Answer: I am proficient in several programming languages, including but not limited to Python, Java, C++, and JavaScript. Each language has its strengths, and I adapt my choice based on the requirements of the project.

Question 15: Can you provide insights into the field of image processing?

Answer: Image processing involves manipulating and analysing images to extract information or enhance visual quality. Techniques include filtering, edge detection, and segmentation. Applications range from medical imaging to computer vision. Understanding image processing is vital for tasks like pattern recognition, object detection, and enhancement of visual data.

Question 16: Could you explain the distinctions between a latch and a flip-flop in digital circuits?

Answer: Latches and flip-flops are sequential logic circuits. A latch is level-sensitive, holding its output as long as the input meets certain conditions. In contrast, a flip-flop is edge-triggered, changing state on a clock signal’s rising or falling edge. Both play crucial roles in storing and processing digital information.

Question 17: Can you provide an overview of modulation in telecommunications?

Answer: Modulation is a process of altering a carrier signal’s properties, such as amplitude, frequency, or phase, to encode information for transmission. It allows efficient data transfer over communication channels by adapting signals to the characteristics of the transmission medium.

Question 18: What is topology?

Answer: Network topology refers to the arrangement of nodes and the interconnections between them in a computer network. Common topologies include star, bus, ring, mesh, and tree. The choice of topology impacts factors like data transmission efficiency, fault tolerance, and scalability.

Question 19: What are different types of data structure?

Answer: Data structures are arrangements for organizing and storing data efficiently. Common types include arrays, linked lists, stacks, queues, trees, and graphs. Each serves specific purposes, optimizing data retrieval, insertion, and manipulation based on application requirements.

Question 20: What controllers did you use?

Answer: In my experience, I have worked with a variety of controllers, including microcontrollers like Arduino, PIC, and STM32. Additionally, I have expertise in using programmable logic controllers (PLCs) for industrial automation applications. Adaptability to different controllers allows me to tackle diverse projects effectively.

Question 21: What is the software development cycle?

Answer: The software development cycle, also known as the software development life cycle (SDLC), is a systematic process for designing, developing, testing, deploying, and maintaining software. It typically consists of phases such as requirements gathering, design, implementation, testing, deployment, and maintenance. This structured approach ensures the creation of high-quality software that meets user needs and is delivered on time and within budget.

Question 22: What’s the difference between ROM & RAM?

Answer: ROM (Read-Only Memory) and RAM (Random Access Memory) are types of computer memory with key differences. ROM is non-volatile memory, meaning its contents are permanent and retained even when the power is off. It stores essential firmware and cannot be easily modified. In contrast, RAM is volatile memory used for temporary storage during a computer’s operation. It is quickly accessible but loses its data when the power is turned off.

Question 23: Can you explain MATLAB?

Answer: MATLAB, short for MATrix LABoratory, is a high-performance programming language and environment primarily used for numerical computing, data analysis, and visualization. It provides a vast array of built-in functions and toolboxes for diverse applications, including mathematics, signal processing, image processing, machine learning, and control systems.

Question 24: Can you explain the functions of MATLAB?

Answer: MATLAB offers a wide range of functions for various applications. It excels in mathematical modeling, simulation, and algorithm development. Some key functions include matrix manipulation, data analysis, plotting and visualization, signal processing, image and video processing, machine learning, and control system design. Its versatility makes it a powerful tool for engineers, scientists, and researchers.

Question 25: Can you explain NAND gate?

Answer: A NAND gate is a digital logic gate that performs a logical operation based on the principles of Boolean algebra. It produces a high output (1) only when both of its inputs are low (0). In other words, it negates the conjunction of its inputs. The symbol for a NAND gate is a triangle pointing to the right with a small circle at its output. NAND gates are fundamental building blocks in digital circuit design and are used to create various logical functions.

Question 26: Why are NAND gates used in VLSI?

Answer: NAND gates are often preferred in VLSI (Very Large Scale Integration) design for their universality. With proper configurations, NAND gates can be used to construct all other logic gates, making them versatile building blocks. This simplifies the design process and reduces the number of different gate types required, leading to more efficient and cost-effective VLSI circuits.

Question 27: What is noise margin?

Answer: Noise margin is the measure of a digital circuit’s tolerance to noise or variations in input levels. It represents the difference between the minimum acceptable voltage for a high logic level (1) and the maximum acceptable voltage for a low logic level (0). A higher noise margin ensures better reliability in the face of signal distortions or fluctuations.

Question 28: Can you explain AM and FM waves?

Answer: AM (Amplitude Modulation) and FM (Frequency Modulation) are modulation techniques used in analog communication. In AM, the amplitude of the carrier wave is varied based on the strength of the audio signal. In FM, the frequency of the carrier wave is altered in response to changes in the audio signal. Both methods encode information for transmission over radio waves.

Question 29: Explain AM and FM modulation.

Answer: In AM modulation, the amplitude of the carrier wave is varied in proportion to the instantaneous amplitude of the modulating signal (audio signal). This variation creates sidebands around the carrier frequency, containing the information to be transmitted.

In FM modulation, the frequency of the carrier wave changes based on the instantaneous frequency of the modulating signal. This modulation technique is known for its resistance to amplitude variations and provides high-quality audio transmission.

Question 30: What is image processing?

Answer: Image processing involves the manipulation and analysis of images to extract information, enhance visual quality, or perform various tasks. It encompasses a wide range of techniques, including image enhancement, segmentation, feature extraction, and pattern recognition. Image processing finds applications in diverse fields such as medical imaging, computer vision, remote sensing, and multimedia.

Question 31: What is a cross compiler?

Answer: A cross compiler is a compiler that runs on one platform but generates executable code for a different platform or architecture. It allows developers to write code on one system and compile it for execution on another system with a different architecture. Cross compilers are commonly used in embedded systems development and for targeting specific hardware platforms.

Question 32: What are the structures in C?

Answer: In C, a structure is a composite data type that allows you to group variables of different data types under a single name. The declaration of a structure defines a collection of fields (members), each with its own data type. Accessing structure members is done using the dot notation.

For example:

struct Point {

int x;

int y;


Question 33: What is an array and pointers in C?

Answer: An array in C is a collection of elements of the same data type, stored in contiguous memory locations. It is defined with a fixed size. Pointers, on the other hand, are variables that store memory addresses. They are often used to manage dynamic memory allocation and facilitate efficient array manipulation by pointing to the array’s first element.

Question 34: What are keywords in C?

Answer: Keywords in C are reserved words that have predefined meanings in the language. They cannot be used as identifiers (variable names or function names) because they are part of the C language syntax. Examples of keywords include int, float, if, while, for, return, and others.

Question 35: Explain an ODD & EVEN program.

Answer: An ODD & EVEN program in C checks whether a given integer is odd or even. Here is a simple example:

#include <stdio.h>
int main() {
int number;
printf("Enter an integer: ");
scanf("%d", &number);
if (number % 2 == 0) {
printf("%d is even.\n", number);
} else {
printf("%d is odd.\n", number);
return 0;

This program takes an integer input, checks whether it’s divisible by 2, and prints whether it’s even or odd accordingly.

Question 36: What is static and dynamic memory allocation?


Static Memory Allocation: Memory is allocated at compile-time and is fixed throughout the program’s execution. Variables and their memory locations are determined during the compilation phase.

Dynamic Memory Allocation: Memory is allocated at runtime using functions like malloc and free in C. It allows for flexible memory usage, enabling the program to allocate and release memory as needed.

Question 37: What is the function of the session layer?

Answer: The session layer, part of the OSI model, manages sessions or connections between applications. It establishes, maintains, and terminates communication sessions, ensuring data integrity, synchronization, and error recovery. It also handles dialog control, allowing for full-duplex or half-duplex communication between devices.

Question 38: Can you explain full wave, half wave rectifier, and bridge?


Half-Wave Rectifier: Converts only one-half of the AC input waveform to pulsating DC. It uses a single diode, allowing current flow only during the positive half-cycle.

Full-Wave Rectifier: Converts both halves of the AC input waveform to pulsating DC. It can be implemented using two diodes in a bridge configuration or using a center-tapped transformer and two diodes.

Bridge Rectifier: Utilizes four diodes arranged in a bridge configuration to rectify both positive and negative half-cycles of the AC input, providing a more efficient conversion of AC to DC.

Question 39: What controllers did you use?

Answer: In my experience, I have worked with various controllers, including microcontrollers such as Arduino, PIC (Peripheral Interface Controller), and STM32. Additionally, I have experience with programmable logic controllers (PLCs) commonly used in industrial automation applications.

Question 40: What is a sensor and actuators?


Sensor: A sensor is a device that detects and measures physical properties or changes in the environment and converts this information into electrical signals or other readable forms. Examples include temperature sensors, motion sensors, and light sensors.

Actuator: An actuator is a device that receives a control signal and converts it into physical action. It is responsible for executing a specific task based on the input it receives. Examples include motors, solenoids, and hydraulic pistons.

Question 41: Can you explain the architecture of 8051?

Answer: The 8051-microcontroller architecture consists of a CPU, RAM, ROM, I/O ports, timers, counters, and a serial communication control. It operates with a Harvard architecture, featuring separate buses for data and program memory.

The CPU processes instructions from the program memory, and the architecture supports a variety of addressing modes. Key components include the ALU (Arithmetic Logic Unit), registers, and multiple interrupt sources.

Question 42: Can you explain sampling theorem?

Answer: The sampling theorem, also known as Nyquist-Shannon theorem, states that to accurately reconstruct a continuous signal from its sampled version, the sampling frequency must be at least twice the highest frequency present in the original signal. This theorem is fundamental in digital signal processing and ensures faithful representation of analog signals in digital systems.

Question 43: What is HTTP?

Answer: HTTP (Hypertext Transfer Protocol) is the foundation of data communication on the World Wide Web. It is an application-layer protocol that facilitates the transfer of hypertext documents, typically in the form of HTML files. HTTP defines how messages are formatted and transmitted and how web servers and browsers respond to various commands.

Question 44: Explain SMTP.

Answer: SMTP (Simple Mail Transfer Protocol) is a protocol used for sending and relaying email messages between email servers. It defines the rules for how email clients send messages to a mail server and how mail servers communicate with each other to deliver emails. SMTP operates over TCP (Transmission Control Protocol) and is a crucial part of the email delivery process.

Question 45: What happens on typing a web address?

Answer: When you type a web address (URL) into a browser and press Enter, several steps occur:

  • The browser checks its cache for the corresponding IP address.
  • If not found, a DNS (Domain Name System) lookup is performed to obtain the IP address associated with the domain.
  • The browser initiates a TCP connection to the web server’s IP address on port 80 (for HTTP) or port 443 (for HTTPS).
  • Once connected, the browser sends an HTTP request for the specific web page.
  • The web server processes the request, retrieves the requested page or resources, and sends them back to the browser.
  • The browser renders the received content, displaying the web page to the user.

Question 46: What are pointers and how are they accessed?

Answer: Pointers in C are variables that store memory addresses. They point to the location of another variable or data structure in the memory. Pointers are accessed by dereferencing, using the * operator. Dereferencing a pointer retrieves the value stored at the memory address the pointer is pointing to.

Question 47: Can you list out some manufacturers of PLC?

Answer: Some manufacturers of Programmable Logic Controllers (PLCs) include:

  • Siemens
  • Allen-Bradley (Rockwell Automation)
  • Schneider Electric
  • Mitsubishi Electric
  • ABB
  • Omron
  • Delta Electronics
  • Bosch Rexroth

Question 48: Can a motor be converted into a generator?

Answer: Yes, a motor can be converted into a generator. When a motor is turned manually or by an external force, it generates electrical energy. This process is known as regenerative braking or generator action. The generated voltage can be harnessed and used as a power source.

Question 49: Can you write a C program for the Fibonacci series?

#include <stdio.h>
void generateFibonacci(int n) {
int first = 0, second = 1, next;
printf("Fibonacci Series up to %d terms: ", n);
for (int i = 0; i < n; i++) {
printf("%d, ", first);
next = first + second;
first = second;
second = next;
int main() {
int n;
printf("Enter the number of terms for Fibonacci series: ");
scanf("%d", &n);
return 0;

Question 50: What are the ranges of FM, AM, and MICROWAVE?

Answer: The frequency ranges are approximate and can vary based on regional standards and specific applications:

AM (Amplitude Modulation): Typically spans from 530 kHz to 1700 kHz for broadcasting.

FM (Frequency Modulation): Generally, falls within the range of 88 MHz to 108 MHz for FM radio broadcasting.

Microwave: Encompasses frequencies ranging from 1 GHz to 300 GHz, commonly used in communication, radar, and cooking applications.

Question 51: What should be connected in between motors and controller for proper working of the motor?

Answer: In between motors and controllers, devices such as motor drivers or motor controllers are commonly connected. These devices act as an interface, managing the power supply and signals between the microcontroller or PLC and the motor. Motor drivers help regulate the voltage, current, and speed of the motor, ensuring proper functioning and protecting the motor from damage.

Question 52: Explain frequency bands in communication with ranges.

Answer: Communication frequency bands are segments of the electromagnetic spectrum allocated for specific communication purposes. Common bands include:

HF (High Frequency): 3 MHz to 30 MHz

VHF (Very High Frequency): 30 MHz to 300 MHz

UHF (Ultra High Frequency): 300 MHz to 3 GHz

SHF (Super High Frequency): 3 GHz to 30 GHz

EHF (Extremely High Frequency): 30 GHz to 300 GHz

Different bands are suitable for various applications like AM/FM radio (HF), TV broadcasting (VHF/UHF), and satellite communication (SHF/EHF).

Question 53: Explain the architecture of 8051.

Answer: The 8051-microcontroller architecture includes:

CPU: Central Processing Unit that executes instructions.

RAM: Random Access Memory for temporary data storage.

ROM: Read-Only Memory for storing the program.

I/O Ports: Input/Output Ports for interfacing with external devices.

Timers/Counters: Peripheral devices for time-related operations.

Serial Communication Control: Handles serial communication.

Interrupt Control: Manages interrupts for multitasking.

Control Registers: Various control registers for configuration.

ALU (Arithmetic Logic Unit): Performs arithmetic and logical operations.

Question 54: What are PLCs?

Answer: PLCs (Programmable Logic Controllers) are industrial digital computers designed for control and automation of manufacturing processes. They monitor inputs, make decisions based on a stored program, and control outputs to automate machinery or processes.

PLCs are widely used in industries for tasks such as controlling production lines, managing equipment, and facilitating real-time monitoring.

Question 55: What is DTMF? Explain how it works.

Answer: DTMF (Dual-Tone Multi-Frequency) is a signaling system used in telecommunication and control systems. It works by assigning a unique pair of audio frequencies to each key on a telephone keypad. When a key is pressed, two simultaneous tones are generated, and these tones represent the selected digit. DTMF is commonly used for telephone keypad input and remote-control applications.

Question 56: Explain flip-flops?

Answer: Flip-flops are digital circuits used to store binary information. They are bistable multivibrators that can be in one of two stable states, typically representing 0 or 1. Common types include SR (Set-Reset), D (Data or Delay), JK, and T flip-flops. They are fundamental building blocks in digital circuits, memory elements, and sequential logic circuits.

Question 57: Write code for the conversion of a number from hexadecimal to binary in C?


#include <stdio.h>
int main() {
char hex[20];
long long binary = 0;
int i = 0;
// Input hexadecimal number
printf("Enter a hexadecimal number: ");
scanf("%s", hex);
// Convert each hexadecimal digit to binary
while (hex[i]) {
long long temp = 0;
if (hex[i] >= '0' && hex[i] <= '9') {
temp = hex[i] - '0';
} else if (hex[i] >= 'A' && hex[i] <= 'F') {
temp = hex[i] - 'A' + 10;
} else if (hex[i] >= 'a' && hex[i] <= 'f') {
temp = hex[i] - 'a' + 10;
binary = binary * 16 + temp;
// Display the binary equivalent
printf("Binary equivalent: %lld\n", binary);
return 0;

Question 58: What is computer networking?

Answer: Computer networking involves connecting multiple computers or devices to share resources and information. It facilitates communication and data exchange between devices, allowing them to work together. Networks can be classified based on their size (LAN, WAN) and their connectivity (wired or wireless). Computer networking enables tasks like file sharing, internet access, and collaborative work.

Question 59: Explain KVL (Kirchhoff’s Voltage Law) & KCL (Kirchhoff’s Current Law)?

Answer: KVL (Kirchhoff’s Voltage Law): It states that the sum of the voltages in any closed loop of a circuit is equal to the sum of the electromotive forces (EMFs) in that loop. In other words, the total voltage around a closed loop is zero.

KCL (Kirchhoff’s Current Law): It states that the total current entering a junction (or node) in a circuit is equal to the total current leaving the junction. In simple terms, the total current flowing into a point in a circuit is equal to the total current flowing out of that point.

Question 60: Full Forms of GPS and GPRS?


GPS: Global Positioning System

GPRS: General Packet Radio Service

Question 61: What is a latch?

Answer: A latch is a digital circuit that can store one bit of information. It is a bistable multivibrator, meaning it has two stable states (0 or 1). Latches are used to store data temporarily in a digital system. They are often employed in sequential logic circuits, such as memory elements or storage devices.

Question 62: What is a servo system?

Answer: A servo system is a closed-loop control system that uses feedback to maintain or control the position, velocity, or other characteristics of a mechanical system. It typically consists of a motor, a sensor (such as an encoder), a controller, and a feedback loop. Servo systems find applications in robotics, automation, and various control systems where precise motion control is required.

Question 63: What is a microcontroller?

Answer: A microcontroller is a compact integrated circuit that contains a processor core, memory, and programmable input/output peripherals. It is designed for embedded systems and is capable of executing a specific set of tasks or functions.

Microcontrollers are commonly used in devices such as embedded systems, appliances, automotive control systems, and various electronic gadgets. They provide a cost-effective and power-efficient solution for controlling specific applications.

Question 64: What is selectivity, fidelity?


Selectivity: Selectivity refers to the ability of a system or device to respond to signals of a specific frequency or wavelength while rejecting or attenuating signals at other frequencies. It is a measure of how well a system can distinguish between different frequencies without interference.

Fidelity: Fidelity in communication systems refers to the accuracy with which a system reproduces the input signal at the output. High fidelity means that the output faithfully represents the input, preserving the original signal’s quality and details.

Question 65: What is a transponder?

Answer: A transponder is a combined transmitter and receiver device used in communication and navigation systems. It receives a signal, processes it, and retransmits it back to the source or to other receivers. Transponders are commonly used in satellite communication, radar systems, and radio-frequency identification (RFID) applications.

Question 66: What’s the difference between a microcontroller and a microprocessor?


Microcontroller: A microcontroller is a compact integrated circuit that contains a processor core, memory, and input/output peripherals. It is designed for embedded systems and is often used to control specific tasks or functions in devices like appliances, automotive systems, or electronic gadgets.

Microprocessor: A microprocessor is the central processing unit (CPU) of a computer. It performs arithmetic and logic operations and manages data flow within a computer system. Unlike a microcontroller, a microprocessor typically does not have integrated peripherals and is used in more general-purpose computing applications.

Question 67: What’s the difference between flip-flop and RAM?


Flip-Flop: A flip-flop is a bistable circuit element that can store one bit of information. It is commonly used in digital circuits for memory storage, sequential logic, and clocked systems. Flip-flops are faster than RAM but are generally used for smaller amounts of data storage.

RAM (Random Access Memory): RAM is a type of computer memory that allows data to be read and written randomly. It is a volatile memory, meaning it loses its content when the power is turned off. RAM is used in computers for temporary data storage and quick access by the CPU.

Question 68: What is a dark zone?

Answer: In the context of telecommunications, a dark zone refers to an area where signal reception or transmission is weak or nonexistent. It can occur in wireless communication due to obstacles, interference, or attenuation of the signal.

In optical fiber communication, a dark zone may refer to a section of the fiber link where the signal strength is insufficient for proper data transmission.

Question 69: What’s the range of mobile communication?

Answer: The range of mobile communication can vary based on factors such as the type of technology used, frequency bands, and environmental conditions. Generally, mobile communication can cover a range from a few meters for Bluetooth and Wi-Fi to several kilometers or more for cellular networks.

Question 70: What is 1G, 2G, 3G, 4G, and 5G? Features? Speed?


1G (First Generation): Analog cellular networks introduced in the late 1970s. Limited to voice calls.

2G (Second Generation): Digital networks, enabling text messaging (SMS). Introduced in the early 1990s.

3G (Third Generation): Improved data transfer, enabling mobile internet. Rolled out in the early 2000s.

4G (Fourth Generation): Enhanced data rates, providing high-speed internet. Introduced around 2010.

5G (Fifth Generation): Ultra-fast data rates, low latency, and massive device connectivity. Began deployment in the 2020s.


1G: Analog voice calls

2G: Up to 0.3 Mbps (GPRS)

3G: Up to 42 Mbps (HSPA+)

4G: Up to 1 Gbps

5G: Up to 20Gbps

Question 71: What is the difference between 5G and 6G?

Answer: 6G is a conceptual stage, and specific standards and features may evolve. However, the general expectations for 6G include even higher data speeds, lower latency, advanced AI integration, and new use cases, such as holographic communication and advanced augmented reality.

Question 72: What’s the difference between GSM and CDMA?


GSM (Global System for Mobile Communications):

  • Uses a SIM card for subscriber identity.
  • More prevalent globally.
  • Allows for easier device switching by swapping SIM cards.
  • Supports time division multiple access (TDMA).

CDMA (Code Division Multiple Access):

  • Does not use SIM cards; subscriber identity is embedded in the device.
  • More common in North America and parts of Asia.
  • Device activation is tied to the network.
  • Utilizes spread spectrum technology.

Question 73: Explain GSM architecture?


GSM architecture consists of the following key components:

Mobile Station (MS): The mobile device used by the subscriber.

Base Station Subsystem (BSS):  Its manages the radio communication with the mobile station.

Base Station Controller (BSC): Its manages multiple BTS and handles call setup, handovers, and frequency hopping.

Network Switching Subsystem (NSS): Manages the switching and routing of calls.

Base Transceiver Station (BTS): Radio equipment responsible for communication with the mobile device.

Mobile Switching Center (MSC): Connects calls, manages call handovers, and performs network management functions.

Home Location Register (HLR): Stores subscriber information and handles call routing.

Visitor Location Register (VLR): Keeps track of the location of mobile devices currently in the network.

Authentication Center (AuC): Verifies the identity of the subscriber.

Equipment Identity Register (EIR): Stores a list of valid mobile equipment on the network.

Operation and Support Subsystem (OSS): Handles operations, maintenance, and support functions for the network.

Question 74: Can you explain the function of the network layer?

Answer: The network layer, which operates at the third layer of the OSI model, is responsible for routing packets from the source to the destination across multiple networks. Its key functions include:

Logical Addressing: Assigns logical addresses (IP addresses) to devices for identification and location.

Routing: Determines the optimal path for data transmission from source to destination through routers.

Packet Forwarding: Breaks down messages into packets and manages their delivery.

Error Handling: Detects and, in some cases, corrects errors in data transmission.

Fragmentation and Reassembly: Divides large packets into smaller fragments for efficient transmission and reassembles them at the destination.

Question 75: What is a Wi-Fi network? Which protocols are used?

Answer: A Wi-Fi network is a wireless local area network (WLAN) that allows devices to connect and communicate wirelessly within a certain range. Wi-Fi uses radio frequency signals for data transmission. Common Wi-Fi protocols include:

802.11a/b/g/n/ac/ax: These are different generations of Wi-Fi standards, each offering improvements in terms of speed, range, and efficiency. The latest standard as of my last update is Wi-Fi 6 (802.11ax).

Question 76: What is MAC?

Answer: MAC stands for Media Access Control. It is a unique identifier assigned to network interfaces for communication on a network. In the context of networking, MAC refers to the hardware address of a device, which is typically burned into the network interface card (NIC) during manufacturing. The MAC address is used for addressing and identifying devices on a network.

Question 77: Can we change MAC? How?

Answer: Yes, it is possible to change the MAC address of a network interface on many devices. On most operating systems, you can change the MAC address using software tools or commands specific to the platform. However, keep in mind that changing the MAC address might violate network policies, and it should be done responsibly. On Windows and Linux, you can use commands like ipconfig or ifconfig to change the MAC address.

Question 78: What is a Firewall?

Answer: A firewall is a network security device or software that monitors and controls incoming and outgoing network traffic based on predetermined security rules. It establishes a barrier between a secure internal network and untrusted external networks, such as the internet.

Firewalls can be hardware-based or software-based and are essential for protecting networks from unauthorized access, cyberattacks, and other security threats. They examine and control data packets to allow or block traffic based on predefined security rules.

Question 79: What is an array?

Answer: An array is a data structure that stores a collection of elements, all of the same data type, in contiguous memory locations. Each element in the array is identified by an index or a key. Arrays are used to store and organize data efficiently, allowing for easy access and manipulation.

Question 80: Regulator of fan, what is the advancement in it?

Answer: Traditional fan regulators used resistive wire wound components to control the speed of the fan by adjusting voltage. Advancements in fan regulators include the use of electronic regulators with features like:

Electronic Control: Utilizes electronic components for smoother and more precise control.

Remote Control: Allows users to control the fan speed remotely.

Timer Function: Enables setting a specific duration for fan operation.

Energy Efficiency: Provides energy-saving features and improved efficiency.

Question 81: Which is better, GPP or DSP processor?

Answer: The choice between a General Purpose Processor (GPP) and a Digital Signal Processor (DSP) depends on the specific application requirements.

GPP (General Purpose Processor): Suitable for general-purpose computing tasks. Examples include Intel and AMD processors used in personal computers.

DSP (Digital Signal Processor): Designed for tasks involving signal processing, such as audio and video processing, communications, and real-time control systems.

The “better” processor depends on the application. GPPs are versatile and handle a wide range of tasks, while DSPs excel in specialized signal processing applications.

Question 82: What is NAND, NOR? Name the ICs of it.


NAND Gate: NAND gate is a digital logic gate that performs the operation of logical AND followed by logical NOT. It produces a low output only when both inputs are high. IC examples include:

7400 series: 74HC00, 74LS00, etc.

NOR Gate: NOR gate is a digital logic gate that performs the operation of logical OR followed by logical NOT. It produces a low output only when both inputs are low. IC examples include:

7400 series: 74HC02, 74LS02, etc.

Question 83: Which is better, NAND, or NOR? Why?

Answer: The choice between NAND and NOR gates depends on the specific requirements of the logic circuit. Both gates are functionally complete, meaning either can be used to build any other logic gate.

NAND Gate Advantages:

  • Simplicity in manufacturing.
  • Easier to fabricate, leading to smaller, faster, and more power-efficient circuits.
  • Commonly used in memory devices.

NOR Gate Advantages:

  • Easier to understand in terms of Boolean expressions.
  • Used in some types of memory cells.
  • Used in certain applications where NOR gates are more convenient.

The choice depends on factors like speed, power consumption, and the specific needs of the circuit being designed. In practice, both NAND and NOR gates find applications in various digital circuits.

Question 84: Can you tell me the names of different ICs used?

Answer: The names of Integrated Circuits (ICs) can vary widely depending on their function and application. Here are a few examples:

555 Timer IC: Used in timer and pulse-width modulation applications.

741 Op-Amp: Operational amplifier IC used in analog circuits.

ATmega328: Microcontroller IC commonly used in Arduino boards.

LM386: Audio amplifier IC.

MAX232: RS-232 line driver/receiver IC.

Question 85: Which controller is used in a printer?

Answer: Printers often use microcontrollers or microprocessors for control and communication. The specific controller can vary based on the type and brand of the printer. Some printers use custom controllers, while others may use general-purpose controllers like ARM-based microcontrollers or dedicated printer controller ICs.

Question 86: What are the different types of data structures?

Answer: Data structures are ways of organizing and storing data to perform operations efficiently. Some common types include:

Arrays: Ordered collection of elements.

Linked Lists: Elements linked together, allowing dynamic size.

Stacks: Last In, First Out (LIFO) structure.

Queues: First In, First Out (FIFO) structure.

Trees: Hierarchical structures like Binary Trees and AVL Trees.

Graphs: Nodes connected by edges.

Hash Tables: Key-value pairs for efficient data retrieval.

Heaps: Specialized tree-based structures used in priority queue

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