The resistive Touch Screen is set up in the following way:

Formed to fit the shape of a display, the glass panel has a coating of uniform resistivity. A polyester cover sheet is tightly suspended over the top of the glass, separated from it by small, transparent insulating dots. The cover sheet has a hard, durable coating on the outer side and a conductive coating on the inner side. With a light touch, the conductive coating makes electrical contact with the coating on the glass.

The controller circuit applies a voltage gradient across the resistive surface of the glass. The voltages at the point of contact are the analog representation of the position touched. The controller digitizes these voltages and transmits them to the computer for processing.

By using 4 wires, a pair of wires on each layer, both signals of X and Y are registered by the controller. When a touch occurs. The touch point introduces a pair of voltages for X and Y direction. The Analog-to-Digital Converter (ADC), which is located on the controller, is then converts these voltage positions into digital numbers. The device driver calculates these digital numbers into display (X,Y) coordinate. Puts the mouse cursor onto the (X,Y) coordinate. Also returns the operating system with mouse left-button-down status, and left-button-up status while the touch is occurred.

The touchpad contains a two-layer grid of electrodes that are connected to a sophisticated full-custom mixed signal integrated circuit (IC) mounted on the reverse side of the pad. The upper layer contains vertical electrode strips while the lower layer is composed of horizontal electrode strips. The IC measures "Mutual capacitance" from each of the horizontal electrodes to each of the vertical electrodes. A human finger near the intersection of two electrodes modifies the mutual capacitance between them, since a finger has very different dielectric properties than air. Position of the finger centroid is precisely determined based on these mutual capacitance changes at various locations and can be detected before a finger actually touches the pad.

The SAW touchscreen is a glass overlay with transmitting and receiving piezoelectric transducers for both the X and Y axes. The touchscreen controller sends a 5 MHz electrical signal to the transmitting transducer, which converts the signal into surface waves. These mechanical waves are directed across the opposite side gather and direct the waves to the receiving transducer, which reconverts them into an electrical signal.

When the front surface of the touchscreen is touched, a portion of the mechanical wave is absorbed, thus changing the received signal. The signal is then compared to a stored reference signal, the change recognized, and a coordinate calculated. This process happens independently for both the X and Y axes. By measuring the amount of the signal that is absorbed, a Z-axis is determined.