Before you start
Objectives: Learn what different input devices can we use to communicate with our computer.
Prerequisites: no prerequisites.
Key terms: keyboard, mouse, kvm, switch, touchscreen, connect, mechanical, optical, trackball, wireless, finger
Keyboard and Mouse
Typically we connect our keyboard with our PC using PS/2 or USB port. Some keyboards can be connected wirelessly via a Bluetooth, infrared (IR), or proprietary radio frequency (RF). A mouse will also use a PS2 port, a USB port or a wireless connection. A wireless mouse and keyboard typically transmit to a receiving device attached to the computer through a USB port. We have several different types of mice. We have a mechanical mice which use a roller ball to detect motion. The problem with this kind of mice is that the roller ball must be cleaned periodically to ensure proper functionality. The second type of mice is optical, which use light rays to detect motion. Optical mice practically don’t require maintenance and they are more accurate. We should also mention a trackball, which is a pointing device that is like an upside-down mechanical mouse. We manipulates the pointer by rolling the ball.
Image 320.1 – Trackball
A touchscreen is actually a monitor that allows input by tapping or writing with fingers or stylus. They are used in tablet PCs, PDAs, mobile phones, kiosks and other devices. We have three different types of touchscreens. The first kind is a capacitive touchscreen which uses a thin electrically charged layer laid over the the monitor screen. When we touch the screen a charge is discharged into our finger, and the location of the touch is calculated and sent to the system. The second type is a resistive touchscreen which uses a glass panel covered with two thin metallic layers. One layer is conductive and the other is resistive. Between those two layers there is a narrow gap. When we touch the screen, those two layers make contact. The location of contact is calculated and sent to the system. The third kind of touchscreens is a surface acoustic wave screens which use acoustic wave transmitters and receivers across the screen surface. When we touch the screen, the signal is interrupted and that location is then calculated and sent to the system.
KVM or Keyboard Video Mouse Switch allows us to use one keyboard, one mouse and one display to manage multiple computers.
Image 320.2 – 4 Port USB KVM Switch
A KVM switch can be physically wired to multiple computers or it can be managed remotely over network. We can use keyboard shortcuts or buttons on the KVM switch to toggle the input/output devices between computers.
We can connect our keyboard and mouse using PS/2, USB or wirelessly. Mice can be mechanical or optical. With trackball we manipulates the pointer by rolling the ball. A touchscreen is a monitor that allows input by tapping or writing with fingers or stylus. KVM Switch allows us to use one keyboard, one mouse and one display to manage multiple computers.