sticking, the key can be removed and cleaned or
replaced.
MOUSE
The mouse is quickly becoming a very popular
input device. Some programs, especially graphic user
interface (GUI) programs, virtually require a mouse.
Mice are available in several shapes and sizes, but
all operate in about the same way. The mouse case is
plastic and designed to fit your hand. On the top of
the mouse are two or more buttons. These buttons are
used to indicate to the computer that an action is
desired at the current location of the pointer. For
example, one popular GUI program will activate a
program when the cursor pointer is placed over a
program icon and the left mouse button is pushed
twice.
If you turn the mouse over, you will see a small
rubber ball. As you move the mouse across the desk
top, this ball rolls and moves the encoders inside the
mouse. Remove the access plate and remove this ball
and you will see two or three rollers. These are the
position encoders that send movement data to the
computer.
Mouse Connections
A mouse can be connected to the computer in
several ways.
These are the mouse port, a serial
mouse, and a bus mouse.
The mouse port is the simplest way to interface
the mouse with the computer. A special, dedicated
port is built into the motherboard of the computer.
The mouse is plugged directly into this port.
The serial mouse is plugged into one of the
computer’s serial ports. When the computer is booted,
the mouse driver searches the ports to determine
which port the mouse is connected to.
computer’s expansion slots.
The mouse then
communicates with the computer across the main bus.
Recently, some manufacturers have introduced the
cordless mouse.
The cordless mouse requires a
special interface card that plugs into one of the
expansion slots. The mouse is equipped with a small,
low-power radio transmitter that transmits mouse
movements to the interface card. The receiver on the
interface card decodes the signal and sends it to the
mouse driver program.
Mouse Maintenance
A mouse requires very little maintenance. About
the only maintenance is to clean the mouse if the
pointer movement is erratic or jerky. To clean the
mouse, turn off the computer and remove the rubber
ball. Clean the ball with a mild detergent and water.
Clean the encoder rollers with a lint-free swab and a
cleaning solvent such as denatured alcohol. Be sure
the ball is completely dry before reinstalling it and
applying power to the computer.
TRACKBALL
The trackball, used with personal computers, is
another pointer device that can be used instead of the
mouse. A trackball is basically a mouse turned over
and the ball exposed. The user rolls the ball, moving
the pointer on the screen. The trackball operates the
same way the mouse does. Many laptop computers
are being manufactured with a trackball installed in
the keyboard, eliminating the need for an external
mouse. Full-size keyboards are also available with a
built-in trackball.
SUMMARY-PERSONAL COMPUTER VIDEO
DISPLAYS AND INPUT DEVICES
This chapter has presented material about video
display monitors, video adapters, and their input
devices.
The following information summarizes
important points you should have learned.
The bus mouse is for users that do not have a free
serial port.
The mouse is plugged into a special
interface board that is installed into one of the
2-6
. . .
