chapter 10

A+ Guide to Managing and Maintaining Your PCFifth Edition

Chapter 10

Supporting I/O Devices

2 A+ Guide to Managing and Maintaining Your PC, Fifth Edition

You Will Learn… How to use ports and expansion slots for add-

on devices

How to install peripheral I/O devices

About keyboards and how to troubleshoot them

About different types of pointing devices

How monitors and video cards relate to the system, and how to troubleshoot them


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


Installation Overview

1. Install the device (internal or external)

2. Install the device driver

3. Install the application software


Ports


Using Ports and Expansion Slots for Add-on Device Ports

Serial

Parallel

USB

IEEE 1394

SCSI

Expansion slots


Port Speeds


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


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


Port Comparison


Default Port Assignments


Serial Port Specifications


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


Pin Connections for a 25-Pin Null Modem Cable


Wire Connections on a 25-Pin Null Modem Cable


Infrared Transceivers Use resources of a serial port for communication

Create a virtual infrared serial port and virtual infrared port for infrared devices

UART (Universal Asynchronous Receiver-Transmitter ) logic on the motherboard controls serial ports on the board

Line-of-sight issue


Universal Asynchronous Receiver-Transmitter

UART is a piece of computer hardware that translates between parallel bits of data and serial bits.

A UART is usually an integrated circuit used for serial communications over a computer or peripheral device serial port.

UARTs are now built into some microcontrollers.


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


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


A Standard Parallel Port


Configuring Parallel Ports

Setup can have up to four different settings for parallel ports

PORT NAME Interrupt # Starting I/O Ending I/O

LPT1 IRQ 7 378 37f

LPT2 IRQ 5 278 27f

LPT 3 IRQ 5 / IRQ 7 278 27A

LPT 4 IRQ 5 / IRQ 7 1378 137A


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


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


USB Ports


USB Host Controller


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


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


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 transferIsochronous 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.


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


IEEE 1394 Cable Connections


Using IEEE 1394 Ports


Installing an Expansion Card in an Expansion Slot


Using Specialized Devices and Extra Ports


Using PCI Expansion Slots PCI bus

Currently the standard I/O bus Uses an interim interrupt between PCI card and

IRQ line to the CPU PCI bus controller

Manages the PCI bus and expansion slots Assigns IRQ and I/O addresses to PCI expansion

cards Use Device Manager to see which IRQ has

been assigned to a PCI device


Using PCI Expansion Slots (continued)


Using ISA Expansion Slots

Configuration is not automated

ISA bus does not manage system resources, as do USB and PCI bus controllers

ISA device must request system resources at startup


Solving Problems with Legacy ISA Expansion Cards

Resource conflicts between two legacy devices

Use Windows Device Manager

Problems using legacy device drivers

Try to locate a 32-bit driver for the device


Solving Problems with Legacy ISA Expansion Cards (continued)

Create empty copy of Autoexec.bat and Config.sys on hard drive then

• boot up into MS-DOS mode

• run setup program from command prompt

• copy appropriate command lines into original versions of Autoexec.bat and Config.sys


Solving Problems with Legacy ISA Cards


Solving Problems with Legacy ISA Cards (continued)


Keyboards

Traditional straight design or ergonomic design

Two technologies for keys making contact

Foil contact

Metal contact

Installing keyboards


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


Keyboard Connectors (continued)


Pinouts for Keyboard Connectors


Pinouts for Keyboard ConnectorsYou'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.)


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.


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


Pointing Devices


How a Wheel Mouse Works


How a Mouse Connectsto 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


Pointing Devices

Touch screens

Other pointing devices

Trackballs

Touch pads


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


Computer Video

Necessary components for video output

Monitors

Video cards


Monitors

Rated by screen size, resolution, refresh rate, and interlace features

Most meet standards for Super VGA

Use CRT (cathode-ray tube) or LCD (liquid crystal display) technology


How a CRT Monitor Works


Choosing the Right Monitor


Monitors Monitors and ELF emissions

Flat panel monitors Active-matrix

Dual-scan passive matrix

Installing dual monitors Increases size of Windows desktop

You must choose to activate a second monitor before it will be used by Windows


Flat Panel Monitors


Video Cards

Methods of data transfer

RGB video port

DVI port

Composite video

S-Video


Methods of Data Transfer


Transferring Data with anS-Video Cable


Video Cards Quality is rated according to how video

subsystem affects overall system performance, video quality, power-saving features, and ease of use and installation

Main features to look for Bus used (VESA, PCI, or AGP)

Amount and type of video RAM it has or can support


AGP Bus


Graphics Accelerators Type of video card that has its own processor

to boost performance

Features reduce burden on motherboard CPU, (eg, MPEG decoding, 3-D graphics, dual porting, color space conversion, interpolated scaling, EPA Green PC support, digital output to flat panel display monitors, application support for high-intensity graphics software)


Video Memory Stored on video cards as memory chips

Amount of data received from CPU is determined by Screen resolution

Color depth

Alpha blending

Several types (VRAM, SGRAM, WRAM, 3-D RAM)


Troubleshooting Video Problems Power light (LED) does not go on; no picture

Power LED is on, no picture on power-up

Power is on, but monitor displays wrong characters

Monitor flickers, has wavy lines, or both

No graphics display on screen or screen goes blank when loading certain programs


Troubleshooting Video Problems (continued) Screen goes blank 30 seconds or one minute

after keyboard is left untouched

Poor color display

Picture out of focus or out of adjustment

Crackling sound


Video Monitors

Configuring or changing monitor settings and drivers in Windows

Changing video driver configuration

Returning to standard VGA settings


Summary

Procedures and guidelines common to most installations, including how to use serial, parallel, USB, and IEEE 1394 ports as well as expansion slots

Essential I/O devices for a PC Keyboard

Mouse

Video

chapter 10

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