4 wire resistive touch screen is the preferred solution for low cost applications.4 wire resistive consists of a conductive touch screens (ITO Glass or Film) and a conductive top layer (ITO Film),touch screens are suspended by many very small spacer dots.When a certain point is touched, the top layer contacts the touch screens and a voltage charged by the controller is applied to the 4 wire resistive panel. The coordinate X axis of the touch point can be detected by measuring the voltage value thru the top ITO layer and the coordinate Y axis of the touch point can be detected in the same way by changing voltage input to the top layer's electrodes.