1. Input/Output
Chapter 16

2. Overview In this chapter, you will learn to
Explain how to support common input/output ports
Identify certain common input/output devices on a PC
Describe how certain specialty input/output devices work on a PC
When gaining attention and establishing common ground, ask questions of the class such as, “How many of you have ever used USB or FireWire devices?” or “Who has used digital camera or a webcam?”
For a WIIFM statement, say to the class, “Imagine someone calling you up and saying everything was working fine on their system until they plugged in a digital camera. Then their keyboard stopped working. They plugged the camera into another computer and everything worked fine. They plugged it back into their computer and the mouse stopped working this time. Why could this happen? In this lesson we’ll learn about this, and more.”

3. Supporting Common I/O Ports
Essentials
CompTIA A+ Essentials
Supporting Common I/O Ports

4. Serial Ports Converts data between serial and parallel devices
RS-232 Standard
Primary standard used for serial devices
Rarely used today Other standards (such as USB) much quicker
COM ports are serial
9-pin connector
Used by modems and other devices

5. Serial Properties Speed set in bits per second
75 bps to 128,0000 bps
Size of data chunks sent
7 or 8 bits
Stop bits
Identify end of chunk
Flow control

6. USB Ports Understanding USB
Host controller in chipset: contains root hub

7. USB Speeds USB 2.0 USB 1.1 To get Hi-Speed Speed is total speed of bus
Runs at 480 Mbps (Hi-Speed)
USB 1.1
1.5 Mbps (Low-Speed) and 12 Mbps (Full-Speed)
To get Hi-Speed
Hi-Speed device must be plugged into Hi-Speed port with Hi-Speed cable
Speed is total speed of bus
Divided between all the devices
Most systems support both 1.1 and 2.0

8. USB Hubs and Cables USB controller supports up to 127 devices
Won’t find 127 USB ports on any computer
Add hubs to add additional ports
Hubs can be powered or unpowered
Cables can’t be longer than 5 meters

9. USB Configuration First rule of USB device installation
Always install driver BEFORE installing device
UVCView shows controllers and hubs
Microsoft tool—free download

10. USB Device Manager shows all USB devices Beware of sleeping devices
Locate USB hub under Universal Serial Bus Controller icon
Has a Power tab to show power properties
Beware of sleeping devices
System tells them to sleep to save power
Sleeping devices no longer appear in Device Manager
Uncheck Allow the computer to turn off this device to save power

11. FireWire Similar to USB USB IEEE 1394 FireWire
Different speeds and different connectors
IEEE 1394
1394a runs at 400 Mbps
1394b runs at 800 Mbps
USB
FireWire

12. FireWire Devices can be connected to a hub or daisy-chained
Up to 63 devices supported
Max cable length can be up to 4.5 meters

13. General Port Issues Basic checks If port bad
Is the port bad or the device bad?
Plug in known good device to check port
If port bad
Check CMOS—turned off?
Check Device Manager—disabled?

14. General Port Issues Check for physical damage Bent, missing pins
Sometimes possible to reshape pins and plugs

15. Common I/O Devices

16. Keyboards Primary method of input USB keyboards
Make sure USB keyboard support option enabled in CMOS
Some settings available in Keyboard applet

17. Cleaning the Keyboard Clean the top with cloth dampened with water
Can use isopropyl alcohol for stubborn dirt

18. Cleaning the Keyboard Cleaning under the keys
Start with compressed air
Can sometimes take the layers apart and clean
Keep track of the location of all keys and parts
Allow sheets to dry before reassembling
Careful when removing keys—can break them

19. Mice Hot keys do exist to work without mouse
Mouse applet in Control Panel
Slightly different in 2000 and XP
Can adjust buttons and speed of movement

20. Mice Two primary technologies Common problem with ball mice
Ball mice—use small round ball
Optical mice—use LEDs or lasers
Common problem with ball mice
They get dirty
Mouse pointer becomes jumpy

21. Cleaning the Mouse Remove the ball Optical mouse
Remove dirt from roller
Optical mouse
Rarely need cleaning
Clean optics when necessary

22. Scanners Enable you to make digital copies of Flatbed scanners Photos
Documents
Drawings
And more
Flatbed scanners
Place document on the glass
Close the lid
Run the software

23. Scanners Software used to capture image Default driver:
TWAIN (Technology Without An Interesting Name)
Common software
Photoshop
Paint Shop Pro
Printer-specific

24. How to Choose a Scanner Consider five primary variables:
Resolution: dots per inch (dpi)
Color depth: bits used for color (8, 16, 24, 36, 48)
Grayscale depth: bits for shades of gray (8, 16, more)
Connection: typically USB or FireWire
Scan speed: seconds
72 dpi
300 dpi
1200 dpi

25. Installing and Scanning Tips
Typically USB or FireWire connections
Install drivers before plugging in
Do the best quality possible first
Then manipulate size and quality for end use
Two resources affect what you can do:
RAM: 600 dpi is about 93 MB
Processor speed

26. Installing and Scanning Tips
Keep the glass clean
Dirty glass results in dirty scans
When moving the scanner
Use the locking mechanism for the scanner light assembly

27. Digital Cameras Storage media—digital film Connection
Secure Digital (SD) card common
About the size of Wheat Thin
Sizes range from 64 MB to 1 GB
Connection
USB and FireWire common
Allow you to read data from card while in camera
Card readers allow you to remove card and plug into reader

28. Digital Cameras Quality measured in megapixels Zoom Form factor
2-megapixel can produce quality 4x6-inch photos
5-megapixel can produce quality 8x10-inch photos
Zoom
Optical zoom—physically built into the lens
Digital zoom—software provides zoom capabilities
Optical zoom more important when comparing camera quality
Form factor
Larger usually means better quality

29. Web Cameras Used for Internet interaction
Biggest issue is image quality
Resolutions between 100,000 to 1.3 million pixels
1.3 megapixels best quality achievable with broadband connection
Frame rate
How many pictures per second
30 frames per second considered best

30. Web Cameras Microphones Configuring webcams
Some webcams have microphones
Can use your own headset
Configuring webcams
USB connections common
Install drivers first

31. Web Cameras Configuring software—common steps
Tell the program you want to use a camera
Tell the program whether you want the camera to turn on automatically when you chat
Configure the image quality
Test the camera
Many cameras now have the ability to track you when you move, to keep your face in the picture. This interesting technology recognizes a
human face and rotates its position to keep your face in the picture. Some companies even add funny extras, such as this webcam program’s animated character, which mirrors your movements as you conference with friends or co-workers.

32. Specialty I/O Devices

33. Biometric Devices Used for authentication Fingerprints Retinal scans
Voice recognition

34. Bar Code Readers
Designed to read standard Universal Product Code (UPC)
Frequently used to track inventory
Includes asset inventory
Also used in point-of-sale systems

35. Touch Screens Monitor with sensing device on face
Detects location of touch
Either by finger or stylus
Responds as if it were a mouse click
Touch screens can be seen in
Information kiosks
PDAs
Point-of-sale systems
Tablet PCs