Comptia A+ note

1. Supporting I/O Devices

2. Basic Principles of
Peripheral Installations
 Both hardware and software must be
installed (hardware is controlled by
software)
 Install all levels of software
 Device driver must be written
specifically for the OS
 More than one peripheral device might
attempt to use same resources
 Update drivers, the firmware, or both

3. Installation Overview
1. Install the device (internal or external)
2. Install the device driver
3. Install the application software

4. Ports

5. Using Ports and Expansion
Slots for Add-on Device
 Ports
– Serial
– Parallel
– USB
– IEEE 1394
– SCSI
 Expansion slots

6. Port Speeds

7. Using Serial Ports
 Transmit data in single bits (serially)
 Nine or 25 pins
 Almost always male
 Originally intended for input and
output devices
 Configured as COM1, COM2, COM3, or
COM4

8. Using Serial Ports
(continued)
 Port assignments are made in CMOS
setup
 Conform to standard interface called
RS-232c
 Data Terminal Equipment (DTE) and
Data Communications Equipment
(DCE) designations

9. Port Comparison

10. Default Port Assignments

11. Serial Port Specifications

12. Null Modem Connection
 Enables data transmission between
two DTE devices without the need for
modems
 Special cable (null modem cable) has
several wires cross-connected to
simulate modem connection

13. Pin Connections for a 25-
Pin Null Modem Cable

14. Wire Connections on a
25-Pin Null Modem Cable

15. Infrared Transceivers
 Use resources of a serial port for
communication
 Create a virtual infrared serial port and
virtual infrared port for infrared devices
 UART logic on the motherboard controls
serial ports on the board
 Line-of-sight issue

16. Using Parallel Ports
 Transmit data in parallel, eight bits at a
time
 Almost always female
 Originally intended for printers
 Can be configured as LPT1, LPT2, or LPT3
 Port assignments are made in CMOS setup
 Avoid using a cable longer than 15 feet to
ensure data integrity

17. Types of Parallel Ports
 Standard parallel port (SPP)
– Allows data to flow in only one direction
– Slowest of the three types
 Enhanced Parallel Port (EPP)
– Bi-directional
 Extended Capabilities Port (ECP)
– Bi-directional
– Uses the DMA channel

18. A Standard Parallel Port

19. Configuring Parallel Ports
 Setup can have up to four different
settings for parallel ports

20. Using USB Ports
 Effortless installation of slow peripheral
devices
 Much faster than regular serial ports; use
higher-quality cabling
 Easier to manage; eliminate need to
manually resolve resource conflicts
 Likely to replace serial and parallel ports

21. Using USB Ports (continued)
 Allow for hot-swapping; are hot-pluggable
 Most current motherboards have one to four
USB ports
 Managed by a USB host controller
 As many as 127 USB devices can be daisy-chained
together using USB devices

22. USB Ports

23. USB Host Controller

24. Requirements for
Preparing to Install a USB
Device
 Motherboard or expansion card that
provides a USB port
 OS that supports USB
 USB device
 USB device driver

25. Installing a USB Device
 Some devices (eg, printers) require the
device to be plugged in before installation
 Some devices (eg, scanners) require the
driver to be installed before the device is
plugged in
 Using Device Manager, verify that USB
controller is installed and working properly

26. Using IEEE 1394 Ports
 Transmit data serially; faster than USB
 Likely to replace SCSI for high-volume, multimedia
external devices
 Provide either a 4-pin or 6-pin connector
 Hot-pluggable
– Can be daisy-chained together and managed by a
host controller using one set of system resources
 Use isochronous data transfer
Isochronous transfers involve large streams of data. This format is used to move
continuous, real-time data streams such as voice or video. Data delivery rates are
predetermined and correspond to the sampling rate o the device.

27. IEEE 1394 Port Standards
 IEEE 1394A
– Supports data speeds up to 1.2 Gbps
– Allows for cable lengths up to 15 feet
 IEEE 1394B
– Supports speeds up to 3.2 Gbps
– Allows for cable length up to 328 feet

28. IEEE 1394 Cable
Connections

29. Using IEEE 1394 Ports

30. Keyboards
 Traditional straight design or
ergonomic design
 Two technologies for keys making
contact
– Foil contact
– Metal contact
 Installing keyboards

31. Keyboard Connectors
 PS/2 connector (or mini-DIN)
– Small, round, with six pins
 DIN (Deutsche Industrie Norm) connector
– Round with five pins
 USB port
 Wireless connection
– Requires a driver

32. Keyboard Connectors
(continued)

33. Pinouts for Keyboard
Connectors

34. Pinouts for Keyboard
Connectors
You'll notice a few things about the table. First, there
are only four actual signals used in the standard
keyboard interface; the extra pins on both types of
connector are not used
(This mismatch means that the connectors were
chosen either from existing designs to save
development costs, or that room was left for future
expansion that was never used. Both occur commonly
in the PC industry.)

35. A Keyboard Adapter
Since the signals are the same for the two types of connector--they just use different
pins. This means that simple mechanical adapters can be made to convert between
the two. These adapters let a keyboard that terminates in a large connector work on a
system that requires a small connector, and vice-versa.

36. Troubleshooting
Keyboards
 A few keys don’t work
 Keyboard does not work at all
 Key continues to repeat after being
released
 Keys produce the wrong characters
 Major spills on the keyboard

37. Pointing Devices

38. How a Wheel Mouse
Works

39. How a Mouse Connects
to the Computer
 Dedicated round mouse port (motherboard
mouse or PS/2-compatible mouse)
 Mouse bus card (bus mouse)
 Serial port (serial mouse)
 USB port
 Y-connection with the keyboard
 Cordless technology

40. Pointing Devices
 Touch screens
 Other pointing devices
– Trackballs
– Touch pads

41. Troubleshooting a Mouse
 Check mouse port connection
 Check for dust or dirt; reboot PC
 Try new mouse
 Uninstall and reinstall mouse driver; reboot PC
 Reboot PC and select logged option from startup
menu to create Bootlog.exe file
– Continue to boot and check log for errors

42. Other Devices
 Scanners
 Web Cameras
 Biometric Devices
 Bar Code Readers
 Touch Screens