Peripheral Devices

Question 1

Three categories of peripheral devices

Answer 1

• Input devices
• Output devices
• Input & Output (I/O) devices

Question 2

Keyboard

Answer 2

Keyboards connect through a USB port. Many keyboards include special function keys that simplify playing music or browsing the internet. Some keyboards include a built-in USB port that can be used to connect other peripheral devices.

Almost every desktop computer requires at least a keyboard to function. Most computers require a keyboard, mouse, and display device in order to function properly

Question 3

Mouse

Answer 3

A mouse can be either wired or wireless.

• A wired mouse uses a USB port to connect to the computer.
• A wireless mouse uses an internal battery for power and uses RF signals (e.g., Bluetooth) to connect to a receiver, which is either connected to a USB port or integrated with the computer.

When selecting a mouse, consider the following:

• Because optical mice use light rays to detect motion, they don’t work on some surfaces.
• Some mice have internal motion sensors, allowing them to detect movements while in the air. This particular device can attach to a user’s head and move the cursor when the head moves.
• You can select mice with additional buttons or a scroll wheel to add functionality.
• High-end gaming mice use a rating of dots per inch (DPI). The rating denotes how many steps (cursor movements) are counted in a single inch

Question 4

Digitizer

Answer 4

A digitizer captures some type of analog signal and converts it into digital data. Some common types of digitizer devices include:

• Graphics Tables—Graphics tablets capture analog stylus strokes written on a pad and convert them to digital data. These are mostly used by graphic artists to capture hand-drawn images.
• Document Scanners—Document scanners are specifically designed to convert paper documents into digital documents, such as PDFs or Rich Text Format files. Document scanners use optical character recognition (OCR) to create editable word processor documents. There are two types of document scanners. Automatic Document Feeder (ADF) scanners automatically scan a stack of papers. Flatbed scanners require that you place each page on a scanning surface one by one.
• 3D Scanners—3D scanners use either physical contact or lasers to map the size and shape of a physical object and convert it into a 3D digital model

Question 5

Game controllers

Answer 5

Game controllers are input devices designed specifically for computer gaming. There are two main types of game controllers:

• Gamepads are handheld controllers with directional controls on the left and buttons on the right.
• Joysticks consist of a stick that pivots on a base. Both the stick and the base have several input buttons. Joysticks are typically used with flight simulator games

Question 6

Scanner

Answer 6

Scanners are used to scan hard-copy images and documents and convert them into digital input for the PC. For example, film photos can be scanned and saved as image files.

Some scanners combine the functionality of a document scanner and are able to create editable documents.

Question 7

Motion sensor

Answer 7

Motion sensors are devices that are able to detect the slightest amount of movement in an area. They are typically used with security systems and require special software and configuration. Two types of motion sensors exist:

• Active motion sensors use ultrasonic sound waves to detect movement in an area. If movement is detected, something happens (e.g., a door opens or an alarm triggers).
• Passive motion sensors detect infrared energy, which is emitted by humans and animals. Passive motion sensors ignore small changes in infrared energy in order to avoid false alarms. Passive motion sensors are sometimes called passive infrared sensors (PIR).

Question 8

Touch pad

Answer 8

Touch pads are typically found on notebook computers and are used in place of a mouse. Users slide their finger on the touch pad to manipulate the cursor. Touch pads can also be used with desktop computers. These touch pads connect to the computer through a USB port and are used instead of a mouse

Question 9

Card reader

Answer 9

A card that contains an embedded microchip or a magnetic strip is inserted into the reader. The reader then scans the chip or strip, verifies its contents, and authenticates the user. Card readers can be stand-alone devices or integrated with other peripherals (e.g., a keyboard or workstation).

Question 10

Biometric scanner

Answer 10

Biometric scanners are used as a form of authentication. They are able to scan users’ unique physical features and use them to verify their identity. Common physical features used by biometric scanners include:

• Retina (eyes)
• Fingerprint
• Face
• Heart beat

Question 11

Barcode reader

Answer 11

A barcode reader is a device that can scan barcodes.

• Barcodes are most commonly used in retail environments at checkout stands. Shipping companies, hospitals, and other organizations use barcodes to track or inventory items.
• Most bar code readers use a laser to scan the barcode. Some use cameras or optical scanners.
• Barcode readers include software that interprets the meaning of the barcode.

By installing a special app, smart phones are able to function as a barcode reader by using the phone’s built-in camera.

Question 12

Near Field Communication (NFC)/ Tap Pay Device

Answer 12

NFC is a set of communication protocols that allows devices to communicate when they are within 1.6 inches of one another. NFC technology is most often employed between a base and a smart phone to allow Tap Pay transactions at stores and restaurants; the user places their phone within proximity of the base and uses an app to make an electronic transactions from their mobile phone. NFC is also used to share contacts, photos, videos, and documents, such as identity documents and key cards.

Question 13

Virtual Reality (VR) Headset

Answer 13

A device worn on the head that covers the eyes and provides separate images for each eye, stereo sound, and motion tracking sensors to create a virtual reality experience for the user. Some headsets also have eye tracking sensors and work with handheld gaming controllers. Virtual reality is widely used to train medical and military professionals. As it becomes more affordable, it is being widely adopted in many fields.

Question 14

Microphone

Answer 14

A microphone converts sound into an electrical signal. Some computers have a built-in microphone, and many headsets and camera systems that connect to computers include microphones.

Question 15

Signature Pad

Answer 15

Signature pads are used to obtain signatures for transactions and agreements. The user uses a stylus on a touch screen to sign his or her name. The signature is captured and stored digitally. Signature pads are commonly used in retail stores and restaurants.

Question 16

Projector

Answer 16

Projectors are display devices that use light to project display output onto a wall or screen. Projectors are often used in classrooms and meetings to display information for a large audience. The brightness of light from projectors and other output devices is measured in lumens. Projectors may use light-emitting diodes (LEDs), organic light-emitting diodes (OLEDs), or other hardware.

Question 17

KVM Switch

Answer 17

A KVM (keyboard, video, mouse) switch allows multiple computers to use a single keyboard, mouse, and monitor. KVM switches have multiple input groups, with each group accepting keyboard, video, and mouse connections from one computer. A single output group connects to the shared peripheral devices. Buttons on the KVM switch are used to toggle between each connected computer.

• Rackmount KVM switches can support up to 16 computers and are typically used in data centers to manage servers from a central console.
• Desktop KVM switches typically support two or three computers, which must be within about 5 meters.
• Networked or remote KVM switches use special hardware devices that send keyboard, mouse, and video content through a network connection.

Question 18

When connecting peripheral devices, consider the following recommendations

Answer 18

• Make sure the computer supports the connection type used by the device.
  
  • Most peripheral devices use USB connectors.
  • Older peripheral devices can use PS/2, serial, or parallel connectors. For these devices, you can use an adapter (e.g., a PS/2 to USB adapter).
  • An expansion card can be added to provide the necessary connections.
• Identify the system requirements of the peripheral device. Some peripheral devices specify a minimum CPU speed, memory size, or OS version.
• Install any necessary drivers or software.
• Configure the device in the OS and verify it is working correctly.

Question 19

USB

Answer 19

The Universal Serial Bus (USB) is the most commonly used connection interface. Almost every device (e.g., laptops, smart phones, tablets, desktop computers) uses USB in some capacity. USB:

• Uses serial communication (bits are sent sequentially)
• Supports plug-and-play and hot plugging (adding and removing devices without rebooting)
• Allows up to 127 devices to be connected to a single bus, directly to the host or via hubs (hubs are limited to five tiers)
• Shares the bandwidth among all devices connected to a single bus
• Provides 5 V of power through the cable

Question 20

USB versions

Answer 20

USB has several versions, all of which are backwards compatible. The following table describes the specifications of each version:

Version

Speed

Data Rate

Max Cable Length

1.1

Low Speed

1.5 Mbps

3 m

Full Speed

12 Mbps

5 m

2.0

Hi-Speed

480 Mbps

5 m

3.0/3.1

SuperSpeed

Up to 5 Gbps

3 m

SuperSpeed+

Up to 10 Gbps

5 m

Question 21

Name and describe this USB type

Answer 21

Type A

A rectangular connector that generally plugs directly into the computer or a hub. Almost all USB cables have one Type-A connector on one of the ends.

Question 22

Name and describe this USB type

Answer 22

Type B

A square connector with two beveled corners. Type-B connectors are mostly used with printers. Some networking devices, such as hubs and modems, also use this connector.

Most USB cables that use this connector have a Type-A connector on one end that plugs into the computer.

Question 23

Name and describe this USB type

Answer 23

Type C

A long, thin oval connector designed to be a universal USB port that works with many devices and connectors.

Question 24

Name and describe this USB type

Answer 24

miniUSB

This connector is used by portable electronic devices, such as digital cameras and some portable storage devices.

Question 25

Name and describe this USB type

Answer 25

microUSB

microUSB connectors are designed for smart phones and tablet devices. microUSB connectors are approximately half the thickness of miniUSB connectors, making them more appropriate for smaller devices.

Question 26

Name and describe this USB type

Answer 26

Type-A USB 3.0

The blue tab indicates that the connector is a USB 3.0 Type-A connector and capable of USB 3.0 speeds. USB 3.0 Type-A connectors are backwards compatible with all previous USB versions.

Question 27

Name and describe this USB type

Answer 27

USB 3.0 Type-B

The USB 3.0 Type-B connector is larger in size and designed to carry both data and power. Due to their increased size, USB 3.0 Type-B connectors cannot be plugged into older USB Type-B ports. However, USB 3.0 peripherals that use this port are able to accept older USB Type-B connectors.

Question 28

Name and describe this USB type

Answer 28

Micro-B

The USB 3.0 Micro-B connector is used by portable devices, such as compact external storage devices, digital cameras, or smart phones.

Question 29

USB devices can be classified according to how they receive power. Name the 2 ways.

Answer 29

Type

Description

Self-Powered

Devices that rely on their own power supply (i.e., they are plugged into an AC outlet) are self-powered devices (sometimes called active devices). USB 2.0 devices that draw more than 500 mA of power are required to be self-powered; USB 3.0 devices that draw more than 900 mA of power are required to be self-powered.

Bus-Powered

USB cables have wires to carry both power and data. Bus-powered (sometimes called passive) devices get their power via the USB cable. Bus-powered devices are classified as low-powered or high-powered devices, depending on the amount of power they draw from the USB bus.

• Low powered devices use 100 mA or less
• High-powered devices use between 100 and 500 mA (up to 900 mA for USB 3.0)

Like USB devices, USB hubs can be bus-powered or self-powered. You cannot connect high-powered devices to a bus-powered hub (you can connect only low-powered or self-powered devices to a bus-powered hub). Therefore, self-powered hubs that provide 500 mA per port are recommended to ensure an adequate power supply to all bus-powered devices that you may wish to connect to the hub.

Question 30

LCD

Answer 30

LCDs (liquid-crystal displays) use liquid crystal technology to display visual information. LCDs are the most common type of display device and range in size from less than an inch to over 10 feet. Modern LCDs use LEDs (light-emitting diodes) to backlight the screen.

• Edge-Lit White LED (EL-WLED or WLED) displays use white LEDs along one edge (usually the top) of the LCD and a light diffuser to backlight the screen. EL-WLED LCDs are the least expensive, thinnest, and most widely used type of LCD.
• Full-array WLED displays have an array of white LEDs behind the screen. Full-array WLED LCDs are able to dim specific regions of the screen, resulting in a much higher contrast ratio than LCDs that use EL-WLED technology.
• RGB-LED displays have an array of special LEDs that are able to emit red, green, and blue light, resulting in superior color accuracy. RGB-LED displays are the most expensive type of backlighting technology.

Older LCD monitors and some LCD HDTVs use cold cathode fluorescent lamps (CCFLs) for backlighting. CCFLs are able to produce better colors than EL-WLED and full-array WLED technologies, but consume a lot more energy and require an internal inverter.

LCDs use one of the following panel technologies:

• TN (twisted nematic) panels are the most common technology used by LCDs. TN panels have very good response times (1–5 ms) and refresh rates (60–144 Hz), so are great for PC gaming.
  
  • TN panels have imperfect color reproduction because only six bits per color can be displayed. They mimic true 24-bit color using dithering and other techniques.
  • TN panels have poor viewing angles and contrast ratios.
• IPS (In-plane switching) panels have the best color reproduction quality and viewing angles among LCDs, making them well suited for graphic artists, designers, and photographers.
  
  • IPS panels have relatively slow response times (5–16 ms) and refresh rates (60 Hz) and have a slight purple tint when viewed from a wide angle.
  • High-end IPS LCDs are very expensive (over $1000).

Because of how they draw frames, LCDs suffer from motion blur when fast movements occur on the display. While motion blur can be reduced with higher refresh rates and lower response times, it can’t be eliminated entirely.

LCD screens are used in the following devices:

• HDTVs
• Computer displays
• Tablets
• Smart phones
• Mobile devices
• Wearable technology

Display devices that are called LED monitors or LED TVs are simply LCDs that use LED backlighting.

Question 31

Plasma

Answer 31

Plasma displays use millions of small cells that contain electrically charged ionized gases. When electrical current is applied to a plasma cell, the gas within the cell forms a plasma and emits a photon of light. Each pixel in a plasma display is made up of a red, green, and blue cell. As with OLED monitors, plasma monitors don’t require a backlight.

Plasma displays have several advantages:

• Plasma displays usually display colors more accurately than LCD displays.
• Because no backlighting is used, plasma displays have high contrast and can produce true black (displays that use backlighting can only display very dark grey).
• Plasma displays have almost no motion blur due to the speed of the gas reaction and the way they draw frames. Because of this, most plasma displays do not specify response times.

Plasma displays have several disadvantages:

• Plasma displays consume two to three times as much power as LCDs.
• They generate much more heat than other display types.
• The gasses inside the cells are sensitive to air pressure fluctuations.
• Plasma displays also suffer from a problem known as image retention (IR). Static images that are displayed for a long time cause the phosphors to overheat, which creates a temporary shadow of the image that is visible even when the display is turned off. If the static image was displayed for too long, screen burn-in can occur, and the shadow image will be permanent.

Plasma displays smaller than 32 inches are not sold because manufacturing them is not profitable.

Question 32

OLED

Answer 32

OLED displays use a thin layer of an organic compound (called an OLED) that lights up in response to an electrical current. OLED displays are more efficient, offer a wider viewing angle, and provide faster response times (< 0.01 ms). However, they are costly to manufacture; OLEDs are the most expensive type of display device. In addition, the pixels in OLEDs (the organic compound) wears out faster than the pixels in LED or plasma displays.

OLEDs can be used in any device that uses a flat-panel display. And because of their size, OLEDs can even be used in textiles (clothing and upholstery).

Flexible materials can be used to create OLED screens, resulting in a bendable—sometimes even foldable—screen. These types of OLEDs are called FOLEDs (flexible OLEDs).

Question 33

Projector

Answer 33

Projectors use a powerful light source (either an LED or laser diode) and a lens to project visual content onto a surface, which is typically a specialized screen. Visual output is achieved by controlling the flow of light.

• LCD projectors use a small internal LCD screen to control light and create images. LCD projectors are inexpensive and can be very compact; some can fit inside a pocket.
  
  • At larger projection sizes, LCD projectors suffer from what is called the screen door effect. This is when each RGB pixel of the display is easily seen.
  • LCD projectors also suffer from motion blur due to the way liquid crystal technology functions.
• DLP projectors use a spinning color wheel to create RGB color and a DMD (digital micromirror device) to control light. The DMD is a small chip that contains millions of tiny mirrors that can redirect light extremely fast. DLP projectors are capable of very high-resolution output at even large projection sizes.
  
  • DLP projectors are much more expensive than LCD projectors.
  • DLP projectors are not as compact as LCD projectors and also use more energy and generate more heat.

Projectors are affected by environmental factors, such as physical obstructions, ambient light, and the surface being projected onto. As such, projectors are only practical in controlled environments

Question 34

Several common video issues along with a possible solutions

Answer 34

Issue

Solution

System does not boot

Computers require a functioning video card in order to boot.

• If the system does not boot and the monitor is blank, check the monitor’s power and video connections.
• If the motherboard returns a POST error (either a code or a series of beeps), ensure the video card is seated properly and has the necessary power connections. If the motherboard still returns a POST error, the video card is bad and should be replaced.

Colors not correct
Colors are not smooth

Incorrect colors are often caused by low color depth settings.

• A color palette is the current list of colors that can be shown on the screen.
• Color shift occurs when a new image must load a different palette than is currently used.
• To correct color shift, increase the color depth of the display.

Blurry images, strange color tints

This problem is often caused by a weak or corrupt signal from the video card.

• Make sure the monitor cable is securely fastened to the video card.
• Check for bent or missing pins.

Image missing, doesn’t fill the screen, skewed, or cut off

Set the display resolution to the monitor’s native resolution. If the display isn’t visible at all, check the monitor’s brightness settings to verify that the screen isn’t dimmed.

Program or system lockup, system crashes, slow video performance

Software or system problems can be caused by incorrect video settings, especially for programs that have high video demands. To correct the problem:

• Update the video card drivers.
• Decrease the video acceleration settings. This decreases the amount of processing done by the video card.

Screen flickers or appears wavy, user reports headaches

A flickering screen can be caused by too low of a refresh rate or a loose video cable.

• Make sure the video cable is properly connected.
• Set the refresh rate to the maximum allowed by the monitor.
• If you cannot increase the refresh rate, try decreasing the resolution size and see if higher refresh rates become available.

Maximum refresh rate is determined by the monitor, the video card, and the video cable. To achieve higher refresh rates, one (or all) of these components may need to be upgraded.

Scrambled or distorted images, blank screen

These problems are typically caused by improper resolution settings or settings outside the scope of the monitor.

• Always set the resolution to the display’s native resolution.
• If necessary, upgrade the monitor to allow for higher resolutions.

Image does not display on a second monitor

For problems with dual-monitor systems:

• Make sure the video card supports dual display.
• Verify that the operating system supports and is configured for dual displays.
• In display settings, extend the desktop onto the second monitor.

Slow performance when drawing screens

By default, Windows automatically adjusts visual effects based on system performance. You can manually modify the types of effects used to optimize how Windows looks and performs.

• In general, the more visual effects that are enabled, the more CPU and graphics processing is required.
• If the system has a slow processor, low memory, or not enough video memory, using visual effects can make the system respond slowly.
• Use the advanced system settings to edit performance settings for visual effects.
  
  1. In File Explorer, right-click This PC and select Properties.
  2. Select Advanced system settings.
  3. On the Advanced tab under Performance, select Settings.
• Optimizing for appearance turns on all visual effects. Optimizing for performance turns off all effects. Effects can be enabled or disabled individually.

Stuck/dead pixels

A pixel that is stuck is in an always on state and displays white. A dead pixel is stuck in an off state and displays black.

• Stuck pixels can be fixed by playing special videos that display a series of colors. Sometimes the video needs to be played for several hours.
• Most of the time, dead pixels are caused by a malfunctioning pixel and cannot be fixed.

If playing the video does not fix stuck or dead pixels, the only way to fix the problem is by replacing the monitor.

Image retention, screen burn-in

Image retention (IR) is caused by a static image being displayed for too long on a screen, creating a shadow of the image that is visible even when the display is off. This is typically a problem for plasma displays only. Most of the time, IR can be fixed by displaying bright white on the screen for an extended period of time. When the image cannot be fixed and is permanent on the screen, it is known as burn-in.

Video files do not play, audio plays but no video

Digital video can be saved in one of several file formats (called codecs). Before you can play a video file, your computer must have the corresponding codecs installed. Many video files use two codecs: one for video and one for audio. If the audio plays but the video does not, you know you have the correct audio codec but need the video codec installed.

Question 35

Hot Swapping/Plugging

Answer 35

Hot swappable devices are devices that can be added and removed without shutting down the computer (technically speaking, hot plug refers to automatically detecting and configuring devices that are added, while hot swap refers to the ability to both add and remove devices).

• Hot swapping must be supported by the BIOS, the bus type or controller, the device, and the driver/operating system.
• USB and FireWire devices are examples of buses and devices designed specifically with hot swap support.
• Most newer SATA drives are hot swappable.
• When you connect a hot swappable device, Windows automatically detects the device, configures a driver (if one is not already installed), and enables the device.
• To remove a hot swappable component, use the Safely Remove Hardware feature to shut down the device before unplugging it from the system.

Question 36

Driver

Answer 36

A driver is program that enables the operating system to interact with hardware devices.

• Both legacy and plug and play devices need drivers to configure and use the device.
• Windows detects newly installed devices and tries to find and load the driver automatically.
  
  • Many drivers are automatically included with the operating system.
  • Some drivers are preinstalled during the operating system installation. Windows will automatically use preinstalled drivers when they match new devices.
  • Windows can search the internet for some drivers.
  • If Windows cannot find a suitable driver, you are prompted to identify alternate locations to search in order to find the correct driver.
• Signed drivers are drivers that include a digital signature. The digital signature proves that the driver:
  
  • Comes from the reported publisher.
  • Has not been altered or modified..
  • Is compatible with the operating system version

Drivers that have passed specific tests on Windows qualify for the Certified for Windows logo and are given a special digital signature.

• An unsigned driver is one without a digital signature; a self-signed driver is one that includes a digital signature, but the identity of the entity that signed the driver cannot be verified. You can install unsigned or self-signed drivers.

In addition to drivers, many devices come with special software that interacts with the driver and the operating system to customize how the device works

Question 37

Plug and Play

Answer 37

Newer systems use plug and play to automatically configure the resources each device needs. Be aware of the following about plug and play:

• The device, the BIOS, and the operating system must support plug and play standards.
• All new devices and operating systems are plug and play compatible.
• Plug and play allows IRQ sharing and ensures that the DMA and I/O resources used by each device are unique.
• A legacy device is one that does not support Plug and Play. In older systems, you had to manually configure the resources used by each device. Troubleshooting legacy systems often involved finding and resolving resource conflicts.
• Although a plug and play system attempts to assign configuration resources around a legacy device’s needs, legacy devices often interfere with a plug and play system’s ability to properly assign resources.

Question 38

System Resources

Answer 38

A computer assigns system resources to hardware devices, and the computer uses these assignments to communicate with the device. You should be familiar with three categories of system resources:

• Devices use IRQ (Interrupt Request) to interact with the CPU. An IRQ allows a device to interrupt the CPU and request processing time. All new devices allow the sharing of an IRQ; older (legacy) devices had to be assigned a unique IRQ.
• DMA (Direct Memory Access) channels are conduits high-speed devices use to bypass the CPU and communicate with RAM directly.
  
  • Devices such as hard drives, sound cards, and FireWire cards use DMA channels to increase the speed of data transfers.
  • Devices must have a unique DMA channel.
• An I/O address (also known as a port address) allows two devices in a computer to send information to each other.
  
  • When a device wants to send information to another device, it addresses the data to the receiving I/O port number and sends it out on the system bus.
  • Each device in a computer must have its own I/O address.

Question 39

Use Device Manager to view installed devices and their status. Describe the steps.

Answer 39

• To open Device Manager:
  
  • Right-click Start and select Device Manager.
  • In the search field on the taskbar, type Device Manager.
  • Press the Windows key + R and type devmgmt.msc.
• Use the device icon to identify the status of the device:
  
  • If the icon for the device is not there, then Windows did not detect the device. Try scanning for new hardware or rebooting the system to detect the device.
  • A normal icon means the device was configured, the appropriate driver was installed, and the device is working properly.
  • An icon with a yellow exclamation mark means the device was detected, but could not be configured properly. In this case, make sure you have the latest driver for the device.
  • An icon with a black down-arrow means the device is disabled.
• To identify the system resources used by a device:
  
  1. Right-click the device and select Properties.
  2. Select the Resources tab.
• To view all resources used by the computer:
  
  • On the file menu in Device Manager, select View > Resources by type (or Resources by connection).
  • Alternatively, press the Windows key + R, type Msinfo32.

Question 40

Be aware of the following when installing devices

Answer 40

• Before purchasing or installing the device, verify that the device is compatible with the version of Windows you are running. You can:
  
  • Check the product documentation and look for the Certified for Windows logo.
  • Check the Microsoft Hardware Compatibility List (HCL).
  • Contact the manufacturer to see if the device is compatible.
• Obtain the latest driver before installation. Instead of using the driver included on the installation disc, check the manufacturer’s website for the latest driver.
• Read the product documentation and follow the instructions for installation. Always follow the manufacturer’s instructions for installing and configuring a device.
• For USB devices, you will typically install the driver prior to connecting the device.
• For internal and non-hot swappable devices, turn off and unplug the system before installing the device.
• Windows will automatically configure a device if:
  
  • The device is fully plug and play capable.
  • There are no resource conflicts or other problems.
  • Windows finds a suitable driver in its driver database.
  • The driver is signed and from a trusted publisher.
• On Windows, unsigned and self-signed drivers must be manually approved. However, you cannot install unsigned drivers on x64 versions of Windows.

Question 41

If you have installed or connected a device but it is not working properly, try the following

Answer 41

• Make sure that devices are plugged in and turned on, that all cables are securely connected, and that expansion cards are properly seated.
• Update the driver to the latest version by downloading the latest driver from the manufacturer’s website.
• Check BIOS/UEFI settings to ensure that the function is enabled.
• Verify that the device is recognized and enabled in Device Manager.
  
  • If the device is not listed in Device Manager, try rescanning for new devices. If that doesn’t detect the device, make sure the device is plug and play compatible and that it is correctly connected and turned on.
  • A yellow question mark identifies a device that Windows could not recognize (no driver was found for the device). To correct this problem, you can right-click the device and search for a suitable driver. In many cases, you will need to download the driver from the manufacturer’s website or install the driver from the device’s installation disc.
  • A down arrow identifies a disabled device. To use a disabled device, enable it in Device Manager.
  • A device with an exclamation mark indicates some kind of problem with the device. The device might be partially working, but has encountered some type of error.
• If the hardware device still does not work, try replacing it with one you know to be good (ideally, one that is exactly the same). For example, if you can’t get the network card working, replace it with one that you know works. If the new one works, then the old one is broken.
• In addition to swapping the cards, try moving the device to a different bus slot or connector.
• For hardware devices that include firmware, try updating the firmware to fix bugs, make new features available, or reduce security risks.
  
  • Download the firmware update from the manufacturer’s website.
  • Before you update the firmware, back up or write down configuration settings.
  • Do not turn off the device during the update.

Question 42

Occasionally, installing a new device will lead to system instability, crashes, BSODs, or even the inability to boot the system. If your computer has any of these problems and you have recently added a new device or updated a driver, try the following:

Answer 42

• If you can boot the system and log on:
  
  • Roll back the driver to a previous version if it was updated recently.
  • Disable the device in Device Manager.
  • Physically remove the device and then uninstall the device in Device Manager to remove the driver from the system. If you uninstall the device without removing it from the system, Windows will detect the device at the next startup and try to reinstall the driver.
  • Revert the system to a restore point before the device was updated or added.
• If the system crashes during startup before you can log on, try booting using the Last Known Good configuration. This starts Windows using the hardware configuration that existed during the last successful logon.

If you install a new device and then restart the computer and log on successfully, using Last Known Good will not help resolve the problem.

• If the system crashes during startup or has a problem after you log on that prevents you from taking actions to correct the problem, try booting into Safe Mode. Once in Safe Mode, disable or uninstall the device, roll back the driver, or revert to a restore point.
• If you cannot boot the system into Safe Mode:
  
  • Enable boot logging to record a detailed list of drivers that are loading during system startup. Examine the Ntbtlog.txt file and identify the last driver that has loaded successfully. The problem device will be after this device.
  • Boot the system from the installation disc and use System Restore to revert the system to a recent restore point.
• If you still can’t start the system, try reducing the system to a minimum state by removing everything except for the CPU, one memory module, the video card, and the hard disk or optical drive for starting the operating system. Once you can start the system, add hardware devices one by one until you find the component that is causing the problem. You can also perform the process in reverse, removing components until the system becomes stable, then adding components back in

Question 43

Check the following when troubleshooting input devices:

Answer 43

• Make sure the device is plugged in securely.
• For stuck or malfunctioning keyboard keys, you might be able to pop the key off and clean the contact underneath. Be aware that replacing the keyboard might be cheaper than spending a lot of time cleaning it.
• Make sure that nothing is on the keyboard as the system boots. If a key is pressed during the boot up process, a 301 (keyboard) error can result. If this happens, then it is more than likely you will have to reboot.
• For wireless devices, check the battery level. Charge the device or change the batteries if necessary.
• If advanced features are not available for the device, update or install the correct device driver.

Question 44

To troubleshoot USB and FireWire devices, consider the following:

Answer 44

• Install the driver before plugging in the device.
• Overloading the USB bus’s power resources can cause devices to not have sufficient power to work properly. Make sure that you are not exceeding 500 mA of power through the USB bus.
• The cable might be too long for the current setup. Remember that shorter cable lengths are best. Try not to use cables that are longer than 3–4 feet.
• Verify BIOS/UEFI settings for onboard USB. Make sure onboard ports are enabled and that the correct USB version is enabled.