Category: IOT Objective Questions

IOT Assessment Questions on “Analog to Digital Converter”.

1. Quantization is the method used for conversion?
a) True
b) False

Answer: a
Clarification: The conversion involves quantization of the input, is it necessarily introduces a small amount of error. Furthermore, instead of continuously performing the conversion, an ADC does the conversion periodically, sampling the input.

2. ENOB stands for_________
a) Effective no of bits
b) Effective no of bytes
c) Efficient no of bits
d) Efficient no of bytes

Answer: a
Clarification: The dynamic range of an ADC is often summarized in terms ofits effective no of bits(ENOB), the number of bits of each measure it returns that are on average not noise. An ideal ADC has an ENOB equal to its resolution.

3. Perfect resolution is possible when?
a) sampling rate greater than thrice the bandwidth of the signal
b) sampling rate greater than twice the bandwidth of the signal
c) sampling rate less than twice the bandwidth of the signal
d) sampling rate less than thrice the bandwidth of the signal

Answer: b
Clarification: If an ADC operates at the sampling rate greater than twice the bandwidth of the signal, then perfect reconstruction is possible given an ideal ADC and neglecting quantization error.

4. Resolution is expressed in __________
a) Bytes
b) Bits
c) Word
d) Nibble

Answer: b
Clarification: The values are usually stored electronically in binary form, so the resolution is usually expressed in bits.

5. The discrete levels available are_________
a) Sides
b) Edges
c) Levels
d) Bytes

Answer: c
Clarification: The number of discrete values available, or levels, is assumed to be power of two.

6. Resolution is expressed in terms of_________
a) Milli volts
b) Ampere
c) Milli ampere
d) Volts

Answer: d
Clarification: Resolution can also be defined electrically, and expressed in volts. The minimum change in voltage required to guarantee a change in the output code level is called least significant bit.

7. The rate of new values is called the sampling rate or sampling frequency.
a) True
b) False

Answer: a
Clarification: The analog signal is continuous I time and it is necessary to convert this to a flow of digital values. It is therefore required to define the rate at which new digital values are sampled from the analog signal. The rate of new values is called the sampling rate or sampling frequency of the converter.

8. How many common ways are there for implementing an ADC?
a) 2 ways
b) 5 ways
c) 8 ways
d) 10 ways

Answer: d
Clarification: The most common ways for implementing ADC are direct conversion, successive approximation, ramp compare, Wilkinson, integrating, delta encoded, pipelined, sigma delta, time interleaved, intermediate FM stage, other types.

9. Other name for data conversion is ________
a) Flash ADC
b) Wilkinson
c) Sigma delta
d) Ramp compare

Answer: a
Clarification: A direct conversion ADC or flash ADC has a bank of comparators sampling the input signal in parallel, each firing for their decoded voltage range.

10. Which ADC narrows the range?
a) Flash ADC
b) Wilkinson
c) Sigma delta
d) Successive approximation

Answer: d
Clarification: A successive approximation ADC uses a comparator to successively narrow a range that contains the input voltage.

11. Clock jitters is caused by __________
a) Sampling rate
b) Spectrum
c) Phase noise
d) Sampling frequency

Answer: c
Clarification: Clock jitter is caused by phase noise. Phase noise is the frequency domain representation of rapid, short term, random fluctuations in the phase of a waveform, caused by time domain instabilities.

12. The analog signal is __________ in __________
a) Continuous, frequency
b) Continuous, time
c) Discrete, frequency
d) Discrete, time

Answer: b
Clarification: The analog signal is continuous in time and it is necessary to convert this to a flow of digital values.

13. Sample and hold circuit is a _______ circuit.
a) Analog device
b) Digital device
c) Both analog and digital
d) Neither analog nor digital

Answer: a
Clarification: An input circuit called a sample and hold performs task, most cases by using a capacitor to store the analog voltage at the input, and using an electronic switch or gate to disconnect the capacitor from the input.

14. Nyquist rate is defined as ___________
a) twice the lowest frequency
b) trice the highest frequency
c) twice the highest frequency
d) trice the lowest frequency

Answer: c
Clarification: Nyqist rate, defined as twice the highest frequency of interest, then all frequencies in the signal can be reconstructed.

15. To avoid aliasing we use a __________ filter.
a) Digital filter
b) Aliasing filter
c) Analog filter
d) Anti-aliasing filter

Answer: d
Clarification: To avoid aliasing, the input to an ADC must be low pass filtered to remove frequencies above half the sampling rate. This filter is called an anti-aliasing filter.

IOT Questions on “IOT Gateway( Wind Intelligent Device)”.

1. Wind River Intelligent Device offers what?
a) Gateway security
b) Application enablement
c) Device Connectivity
d) All of the mentioned

Answer: d
Clarification: Wind River Intelligent Device Platform XT offers:
Gateway security: Secures communication channel, the data and the end device
Application Enablement: Provides JAVA OSGi application environment is provided
Device connectivity: Connection between devices using MQTT protocol
Remote device management: Supports well established management protocol such as TR-069.

2. Pre integrated and smart connectivity enables what?
a) Long term security
b) Products life span increases
c) Saves time and cost
d) Secure remote management

Answer: c
Clarification: Connectivity, manageability, and security are core IoT building blocks, essential for reducing device manufactures, time-to-market, complexity, and risk. Wind River Intelligent Devices has Connectivity benefit which enables rich network option s to save development time and costs.

3. Does manageability provide what?
a) Saves time and cost
b) Product life span increases
c) Long term security
d) Secure remote management

Answer: a
Clarification: Connectivity, manageability, and security are core IoT building blocks, essential for reducing device manufactures, time-to-market, complexity, and risk. Wind River Intelligent Devices has manageability benefit which reduces development time while increases the product‘s life span and uptime.

4. What will Security provide?
a) Saves time and cost
b) Product life span increases
c) Long term security
d) Secure remote management

Answer: c
Clarification: Connectivity, manageability, and security are core IoT building blocks, essential for reducing device manufactures, time-to-market, complexity, and risk. Wind River Intelligent Devices has security benefit which are designed for IoT software development to protect critical data throughout the device lifecycle.

5. Wind River software.
a) True
b) False

Answer: a
Clarification: Wind River, a wholly owned subsidiary of Intel corporation, is a world leader in delivering software for intelligent connected systems.

6. Wind River is introduced by ____________
a) IBM
b) Intel
c) Tech Mahindra
d) Syntel

Answer: b
Clarification: Wind River is introduced by Intel.

7. Wind River provides what?
a) Safe and Secure
b) Secure remote management
c) Save time and cost
d) Product life time increases

Answer: a
Clarification: Wind River the technology and expertise that enables the innovation and deployment of safe, secure, and reliable intelligent systems.

8. Which transportation brings new control?
a) Route Navigation
b) Industrial automation
c) Smart Energy
d) Building Automation

Answer: d
Clarification: Building Automation bring new control, visibility, and efficiencies for reducing power consumption, ensuring safety, and providing services to new and existing buildings.

9. Which transportation brings intelligence to their operations?
a) Building Automation
b) Industrial Automation
c) Smart Energy
d) Route Navigation

Answer: b
Clarification: Wind River helps industrial manufactures bring intelligence to their operations. Gain insights from your machine data with smart devices management.

10. Which transportation build more intelligent energy infracture?
a) Building Automation
b) Industrial Automation
c) Smart Energy
d) Route Navigation

Answer: c
Clarification: Smart energy builds more intelligent energy infrastructure by combining traditional and emerging power sources for the delivering of cleaner, safer, and more economical energy. Perform power management tasks with finer precision and faster response time.

IOT Multiple Choice Questions on “Cloud – Runtime Adaption Engine”.

1. QoE stands for _________
a) Quality of Energy
b) Quality of Experience
c) Quality of Envelop
d) Quality of Encryption

Answer: b
Clarification: If the light weight query engine returns a poor result, then the user may have to issue my query redundantly to the cloud based query processing engine with the hope of getting a better result. This may hurt the overall Quality of Experience.

2. The RAE learns the _________ algorithm to learn the most cost effective policy.
a) Logistic Regression
b) Device/cloud algorithm
c) QoE algorithm
d) Anatomous algorithm

Answer: a
Clarification: The RAE learns the logistic regression algorithm to learn the most cost effective policy for distributing the task among devices and cloud, given the resource state.

3. _________ is the weighted sum of resource state, network, and cpu.
a) Logistic Regression
b) Cloud
c) Device
d) Cost function

Answer: d
Clarification: The cost function is the weighted sum of resource state, network, and CPU usage.

4. The policy obtained by running logistic regression is enforced by _________ module.
a) Device/cloud section
b) Only device
c) Only Cloud
d) Cost function

Answer: a
Clarification: The policy obtained by running logistic regression is enforced by Device/cloud section module, based on the expected cost value for a given task.

5. The mechanism of the RAE is _________ which can be deployed on each device and cloud.
a) QoE
b) Logistic regression
c) Anatomous agent
d) Device/cloud

Answer: c
Clarification: The mechanism of the RAE is anatomous agent, which can be deployed on each device and cloud.

6. OAD stands for ___________
a) Optimal Application Distribution
b) Orientational Application Distribution
c) Orientation Application Development
d) Optimal Application Development

Answer: a
Clarification: The exponential growth of cloud service offering in the last year has increased the number of alternative for engineering and re-engineering applications to be partially or completely run in a cloud environment.

7. _________ enables the application developer to enhance the application design.
a) Cloud Blueprint
b) TOSCA standard
c) Both Cloud blueprint and TOSCA standard
d) Utility function

Answer: c
Clarification: TOSCA standard and Cloud Blueprint enable the application developer to enhance the application design by providing the means to model which cloud offering is used to host which parts of the application stack.

8. _________ process must support the analysis and evaluation of the application topology.
a) Support of different Migration types
b) Enrichment of Topology specification
c) Management and Configuration
d) Top-down and bottom-up

Answer: d
Clarification: Top-down and bottom-up application evaluation process must support the analysis and evaluation of the application topology alternatives both based on previous knowledge and empirical analysis, and during the application productive phase.

9. _________ process has to support the definition of application topologies in various formats.
a) Top-down and bottom-up
b) Enrichment of Topology specification
c) Management and Configuration
d) Support of different Migration types

Answer: b
Clarification: Enrichment of Topology specification process has to support the definition of application topologies in various formats such as TOSCA or Blueprints and must consider non-functional aspects specified as extension of the previous formats.

10. Any tool providing _________ process must provide management and configuration for cloud services.
a) Top-down and bottom-up
b) Enrichment of Topology specification
c) Management and Configuration
d) Support of different Migration types

Answer: c
Clarification: Any tool providing Management and Configuration process must provide management and configuration for cloud services from different providers covering all cloud service and delivery models.

11. In order to re- distribute an application _________ process has to support all cloud native and non cloud native applications.
a) Top-down and bottom-up
b) Enrichment of Topology specification
c) Management and Configuration
d) Support of different Migration types

Answer: d
Clarification: In order to re- distribute an application support of different migration types process has to support all cloud native and non cloud native application types identified.

12. _________ process must support the characterization of different adaptation actions.
a) Characterization of adaptation strategies
b) Independence of Architectural Paradigm
c) Support and reaction to application resources
d) Support of hardware

Answer: a
Clarification: Characterization of adaptation strategies process must support the characterization of different adaptation actions that can be used during run time for a given application.

13. In _________ the application to be re directional is based on 3-layered architecture.
a) Characterization of adaptation strategies
b) Independence of Architectural Paradigm
c) Support and reaction to application resources
d) Support of hardware

Answer: b
Clarification: In Independence of Architectural Paradigm the application to be re directional is based on 3-layered architecture, must be supported.

14. As the workload of an application is subjected to fluctuation over time _________ process must support the identification.
a) Characterization of adaptation strategies
b) Independence of Architectural Paradigm
c) Support and reaction to application resources
d) Support of hardware

Answer: c
Clarification: s the workload of an application is subjected to fluctuation over time support and reaction to application resources demand evolution process must support the identification.

15. _________ process must consider such characteristics for optimizing the overall application performance.
a) Characterization of adaptation strategies
b) Independence of Architectural Paradigm
c) Support and reaction to application resources
d) Support of hardware

Answer: d
Clarification: Support of hardware, software, application characteristics process must consider such characteristics for optimizing the overall application performance.

IOT online quiz focuses on “IoT Characteristics and Reliability Issues”.

1. Which characteristics involve the facility the thing to respond in an intelligent way to a particular situation?
a) Intelligence
b) Connectivity
c) Dynamic Nature
d) Enormous Scale

Answer: a
Clarification: IoT comes with the combination of algorithms and computation, software and hardware that makes it smart. Ambient Intelligence in IoT enhances its capabilities which facilitate the things to respond in an intelligent way to a particular situation.

2. ________ empowers IoT by bringing together everyday objects.
a) Intelligence
b) Connectivity
c) Dynamic Nature
d) Enormous Scale

Answer: b
Clarification: Connectivity empowers IoT by bringing together everyday objects. Connectivity of these objects is pivotal because simple object level interactions contribute towards collective intelligence in IoT network.

3. The collection of data is achieved with ________ changes.
a) Intelligence
b) Connectivity
c) Dynamic Nature
d) Enormous Scale

Answer: c
Clarification: The primary activity of Internet of Things is to collect data from its environment, this os achieved with the dynamic changes that take place around the devices.

4. The number of devices that need to be managed and that communicate with each other will be much larger.
a) Intelligence
b) Connectivity
c) Dynamic Nature
d) Enormous Scale

Answer: d
Clarification: The number of devices that need to be managed and that communicate with each other will be much larger than the devices connected to the current internet.

5. ________ Provide the means to create capability that reflects true awareness of the physical world and people.
a) Sensors
b) Heterogeneity
c) Security
d) Connectivity

Answer: a
Clarification: Sensing technologies provide the means to create capability that reflects true awareness of the physical world and people in it. The sensing information is simply the analogue input from the physical world.

6. ________ in IoT as one of the key characteristics, devices have different hardware platforms and networks.
a) Sensors
b) Heterogeneity
c) Security
d) Connectivity

Answer: b
Clarification: Heterogeneity in IoT as one of the key characteristics, devices have different hardware platforms and networks. And can interact with other devices or services platforms through different networks.

7. IoT devices are naturally vulnerable to ________ threats.
a) Sensors
b) Heterogeneity
c) Security
d) Connectivity

Answer: c
Clarification: IoT devices are naturally vulnerable to security threats. There is a high level of transparency and privacy issues with IoT.

8. Which challenge comes under IoT devices, reliable bidirectional signaling.
a) Signaling
b) Security
c) Presence detection
d) Power consumption

Answer: a
Clarification: With connected IoT devices, reliable bidirectional signaling is essential for collecting and routing data between devices.

9. Which challenge comes under securing the information?
a) Signaling
b) Security
c) Presence detection
d) Power consumption

Answer: b
Clarification: Security is a huge umbrella, but it’s paramount in Internet of Things connectivity.

10. ________ gives an exact, up to the second state of all devices on a network.
a) Signaling
b) Security
c) Presence detection
d) Power consumption

Answer: c
Clarification: Its important to immediately know when an IoT device drops off the network and goes offline and when comes online back. Presence detection of IoT devices gives an exact, up to the second state of all devices on a network.

11. Which challenge comes when we use many devices on the same network?
a) Signaling
b) Security
c) Presence detection
d) Power consumption

Answer: d
Clarification: You need minimal battery drain and low power consumption. You can’t afford to use up 100% of an IoT devices small and expensive embedded CPU power.

12. ________ a cellular network is expensive, especially with many IoT devices.
a) Signaling
b) Security
c) Bandwidth
d) Power consumption

Answer: c
Clarification: In addition to power and CPU, bandwidth consumption is another challenge for IoT connectivity. Bandwidth on a cellular is expensive, especially with many IoT devices.

13. Which of the following issues are considered in IoT?
a) Security Issue
b) Reliablity Issue
c) Standard Issue
d) All issues

Answer: d
Clarification: We should be very careful while building IoT as it has the following issues:
Security Issue
Reliablity Issue
Standard Issue.

14. SBC stands for?
a) Standard Building Center
b) Smart Business Center
c) Standard Business Center
d) Smart Building Center

Answer: b
Clarification: One of the key subsystems from point of view of security of the complex IoT system is a smart business center system.

15. IoT is a paradigm that involves ubiquitous presence in the environment.
a) True
b) False

Answer: a
Clarification: IoT is a paradigm that involves ubiquitous presence in the environment of different things that are using wireless and wire networks.

IOT Multiple Choice Questions on “Microcontroller (8051- Pin, Registers, Timers)”.

1. Number of pins in 8051 microcontroller with ________ package.
a) 40 pin with LLC
b) 60 Pin with QFP
c) 40 pin with DIP
d) 60 pin with QFP

Answer: c
Clarification: The 8051 family members have different packages, such as DIP(Dual In Line), QFP(Quad Flap Package), LLC(Leadless Chip Carrier) they all have 40 pins that are dedicated to different functions. Especially 8051 have a Dual in Line package.

2. Does an 8051 microcontroller need external oscillator to run?
a) True
b) False

Answer: a
Clarification: The 8051 has an on chip oscillator but requires an external oscillator clock to run it. Most often a quartz crystal oscillator is connected to inputs XTAL1 and XTAL2.

3. We use any other frequency source other than crystal oscillator.
a) True
b) False

Answer: a
Clarification: A frequency source other than crustal oscillator is used. It can be a TTL oscillator, it should be connected to XTAL1 and XTAL2 id left unconnected.

4. Reset work is __________
a) To make program counter zero but values in registers values are made as zero
b) Program counter is not zero but values in registers values are made as
Zero
c) Program counter not zero but values in registers values remain same
d) To make program counter zero but values in registers values remain same

Answer: d
Clarification: It is an input pin and active high. When we apply a high pulse it terminates all activities and it cost all the values in the register to be zero. It will also set program counter to zero.

5. What is the minimum no of cycles required for reset operation?
a) 3 cycle
b) 2 cycles
c) 1 cycles
d) 4 cycles

Answer: c
Clarification: When power is turned on, the circuit holds the RST pin high for an amount of time that depends on the capacitor value and the rate at which it changes. To ensure a valid reset the RST pin must be held high long enough to allow the oscillator to start up plus two machine cycles.

6. PSEN stands for ________
a) Program Select Enable
b) Peripheral Store Enable
c) Program Store Enable
d) Peripheral Select Enable

Answer: c
Clarification: This is an output pin. In an 8031-based system in which an external ROM holds the program code, this pin is connected to the OE pin of the ROM.

7. Find the machine cycle for AT89C51 if XTAL = 11.0592MHz.
a) 90.42us
b) 361.68us
c) 1.085us
d) 150.145us

Answer: b
Clarification: Machine cycle = No.of cycles/frequency
Time = 1/frequency
Time(ns) = 1/11.0592MHz
= 90.42ns
Machine cycles = 12*90.42
= 1.085us.

8. What is the operation for mode 0?
a) 13-bit timer mode, 8-bit timer/counter THx and TLx as 5-bit prescalar
b) 16-bit timer mode, 16-bit timer/counter THx and TLx are cascaded, no prescalar
c) 8-bit auto reload mode, 8-bit auto reload time/counter; THx holds a value which is to be reloaded into TLx each time it overflows
d) Spilt timer mode

Answer: a
Clarification: Mode 0 is exactly same like mode 1 except that it is a 13-bit timer instead of 16-bit. The 13-bit counter can hold values between 0000 to 1FFH in Th-Tl.

9. What is the operation for mode 1?
a) 13-bit timer mode, 8-bit timer/counter THx and TLx as 5-bit prescalar
b) 16-bit timer mode, 16-bit timer/counter THx and TLx are cascaded, no prescalar
c) 8-bit auto reload mode, 8-bit auto reload time/counter; THx holds a value which is to be reloaded into TLx each time it overflows
d) Spilt timer mode

Answer: b
Clarification: It is a 16-bit timer; therefore it allows value from 0000 to FFFFH to br loaded into the timer’s register TL and TH. After TH and TL are loaded with a 16-bit initial value, the timer must be started.

10. Which is the operation for mode 2?
a) 13-bit timer mode, 8-bit timer/counter THx and TLx as 5-bit prescalar
b) 16-bit timer mode, 16-bit timer/counter THx and TLx are cascaded, no prescalar
c) 8-bit auto reload mode, 8-bit auto reload time/counter; THx holds a value which is to be reloaded into TLx each time it overflows
d) Spilt timer mode

Answer: c
Clarification: It is an 8 bit timer that allows only values of 00 to FFH to be loaded into the timer’s register TH. After TH is loaded with 8 bit value, 8051 gives a copy of it to TL.

11. Which is the operation for mode 3?
a) 13-bit timer mode, 8-bit timer/counter THx and TLx as 5-bit prescalar
b) 16-bit timer mode, 16-bit timer/counter THx and TLx are cascaded, no prescalar
c) 8-bit auto reload mode, 8-bit auto reload time/counter; THx holds a value which is to be reloaded into TLx each time it overflows
d) Spilt timer mode

Answer: d
Clarification: Mode 3 is also known as a split timer mode. Timer 0 and 1 may be programmed to be in mode 0, 1 and 2 independently of similar mode for other time.

12. Function of IE1 in TCON register?
a) External interrupt 1 Edge flag. Not related to timer operations
b) External interrupt 1 Edge flag. Not related to timer operations
c) External interrupt 0 single type control bit
d) External interrupt 1 to be triggered by a falling edge signal

Answer: a
Clarification: TCON register has 8 bits. 3rd bit has an IE1 register. This is an external interrupt.

13. 8051 controller contains how many registers?
a) 5
b) 3
c) 1
d) 2

Answer: d
Clarification: 8051 microcontroller has 2 types of registers. They are Special Function Registers and the other is General purpose register. Each of having 128KB of memory. And GPR is a Byte addressable register and SFR is a Bit addressable register.

14. General purpose memory is called as ________
a) ROM memory
b) RAM memory
c) SRAM memory
d) EPROM memory

Answer: b
Clarification: The general purpose memory is called as the RAM memory of the 8051 microcontroller, which is divided into 3 areas such as banks, bit-addressable area, and scratch-pad area.

15. Which timer register has both timers in it?
a) TMOD
b) TCON
c) Both TMOD and TCON
d) Neither TMOD nor TCON

Answer: a
Clarification: In the TMOD register, lower 4 bits are set for timer0 and the upper 4 bits are set aside for timer1. In each case, the lower 2 bits are used to set the timer mode and upper 2 bits to specify the operation.

IOT Multiple Choice Questions on “UART Protocol”.

1. GPS module like SIM900/800 uses which protocol?
a) UART protocol
b) USART protocol
c) SPI protocol
d) I2C protocol

Answer: a
Clarification: GSM/GPS modules like SIM900/800 uses UART communication for accepting AT commands that are used to control them and gather the replies.

2. Finger print sensor uses which interface?
a) USART protocol
b) UART protocol
c) SPI protocol
d) I2C protocol

Answer: b
Clarification: Projects that use RFID modules can be built with modules that have a UART interface. This even applies to some finger print sensors.

3. RS232 is used for long range wired communication.
a) True
b) False

Answer: a
Clarification: For long range communications we can convert UART protocol using an external IC to RS232 or RS485, the latter of which can be used for wired communication @100 kbits/sec up to 1.2km.

4. UART is similar to _________
a) SPI protocol
b) I2C protocol
c) HTTP protocol
d) MQTT protocol

Answer: b
Clarification: UART(Universal Asynchronous Receiver/Transmitter) is a small, efficient communication device, similar to I2C.

5. What does UART contain?
a) Parallel register
b) Shift register
c) Clock
d) Parallel shift register

Answer: b
Clarification: UART contains a shift register, which is the fundamental method of conversion between serial and parallel forms.

6. Communication in UART is ___________
a) Only simple
b) Only duplex
c) Only full duplex
d) Simplex, half duplex, full duplex

Answer: d
Clarification: Communication may be simplex(in one direction only no provision for the receiving device to send data back to the transmission device), full duplex(both devices send and receive data at the same time), half duplex(devices takes turns transmitting and receiving).

7. Start bit of UART is logic high.
a) True
b) False

Answer: b
Clarification: The start bit is logical low. The start bit signals the receiver that a new character is coming.

8. Which error occurs when the receiver can’t process the character?
a) Overrun error
b) Underrun error
c) Framing error
d) Break condition

Answer: a
Clarification: An over run error occur when the receiver cannot process the character that just came in before the next one arrives. If the CPU or DMA controller does not service the UART quickly enough and the buffer become full, an over run will occur, and incoming will be lost.

9. What is WD1402A?
a) SPI
b) USART
c) SPIUART
d) I2C

Answer: c
Clarification: WD1402A is the first single chip UART on general sale. Introduced about 1971. Compatible chip included the Fairchild TR1402A and the general instruments AY-5-1013.

10. What is the speed of the 8250 UART?
a) 4800bits/sec
b) 1200bits/sec
c) 12000bit/sec
d) 9600bits/sec

Answer: d
Clarification: The 8250 UART has one character buffer for the receiver and the transmitter each, which meant that communications software performed poorly at speed above 9600bits/sec, especially it operating under a multitasking system or if handling interrupts from disk controllers.

11. Which error occurs when UART transmitter has completed sending a character and the transmit buffer is empty?
a) Overrun error
b) Underrun error
c) Framing error
d) Break condition

Answer: b
Clarification: An Under run error occurs when UART transmitter has completed sending a character and the transmit buffer is empty. In asynchronous mode this is treated as an indication that no data remains to be transmitted.

12. Which error occurs when the designated start and stop bits are not found?
a) Overrun error
b) Underrun error
c) Framing error
d) Break condition

Answer: c
Clarification: A framing error occurs when the designated start and stop bits are not found. If the data line is not in the expected state when the stop bit is expected, a framing error will occur.

13. Which error occurs when the parity of the number of 1 bit disagrees with that specified by the parity bit?
a) Overrun error
b) Underrun error
c) Framing error
d) Parity error

Answer: d
Clarification: A parity error occurs when the parity of the number of 1 bit disagrees with that specified by the parity bit. Using parity is optional, so this error will only occur if parity checking has been enabled.

14. A __________ occurs when the receiver input is at the space level.
a) Overrun error
b) Underrun error
c) Framing error
d) Break condition

Answer: d
Clarification: A break condition occurs when the receiver input is at the space level for longer than some duration of time, typically, for more than a character time.

15. The term break derives from ___________ signaling.
a) Current loop
b) Voltage loop
c) Power loop
d) Current and Power loop

Answer: a
Clarification: The term break derives from current loop signaling, which was the traditional signaling used for teletypewriters.