CompTIA A_ Certification All-In-One Exam Guide, Seventh Edition - Michael Meyers [314]
PCs use biometrics for security. Biometric devices scan and remember unique aspects of various body parts such as your retina, iris, head image, or fingerprint, using some form of sensing device such as a retinal scanner. This information is used as a key to prevent unauthorized people from accessing whatever the biometric device is securing. Most biometric devices currently used in PCs secure only themselves. The USB thumb drive in Figure 18-42 has a tiny fingerprint scanner. You slide your finger (any finger you choose) over the drive to unlock the contents of the thumb drive.
Figure 18-42 USB thumb drive with fingerprint scanner (photo courtesy of Lexar Media, Inc)
Less common are biometric security devices that secure entire computers. The Microsoft fingerprint scanner is a USB device that replaces standard user name and password security. Figure 18-43 shows the scanner built into a keyboard. When a program or Web site asks for a user name and password, you simply press your finger against the fingerprint scanner. It confirms your identity (assuming your fingerprint matches), and then special software that comes with the scanner supplies the program or Web site with your stored user name and password.
Biometric devices are also used for recognition. Recognition is different from security in that the biometric device doesn’t care who you are, it just wants to know what you’re doing. The best example of this is voice recognition. Voice recognition programs convert human voice input into commands or text. Voice recognition for PCs has been around for some time. Although it has never achieved enough accuracy to replace a keyboard completely, voice recognition is common in devices that have a limited number of commands to interpret, such as cell phones and PDAs. If you speak the words
Figure 18-43 Microsoft fingerprint scanner on a keyboard
“Call Mike Meyers” into your smartphone, your phone knows what to do—at least, my phone does!
No matter what biometric device you use, you use the same steps to make it work:
1. Install the device.
2. Register your identity with the device by sticking your eye, finger, or other unique body part (Why are you snickering?) into the device so it can scan you.
3. Configure its software to tell the device what to do when it recognizes your scanned identity.
Bar Code Readers
Bar code readers are designed to read standard Universal Product Code (UPC) bar codes (Figure 18-44). We read bar codes for only one reason—to track inventory. Bar code readers enable easy updating of inventory databases stored on PCs. Bar code readers are just about the oldest “specialty” I/O device used with PCs.
Figure 18-44 Typical UPC code
Two types of bar code readers are commonly found with PCs: pen scanners and hand scanners. Pen scanners look like an ink pen and must be swiped across the bar code (Figure 18-45). Hand scanners are held in front of the UPC code while a button is pressed to scan. All bar code readers emit a tone to let you know the scan was successful.
Older bar code readers used serial ports, but all of the newer readers use either PS/2 or USB ports. No configuration is usually necessary, other than making sure that the particular bar code reader works with whatever database/point of sale software you use. When in doubt, most people find the PS/2-style bar code readers work best, as they simply act like a keyboard. You plug the reader into your keyboard port and then plug your keyboard into the reader. Then all you need is software that accepts keyboard input (and what one doesn’t!), and it will work.
Figure 18-45 Pen scanner (photo courtesy of Wasp® Barcode Technologies)
Touch Screens
A touch screen is a monitor with some type of sensing device across