DIP switch, also known as dual in-line package switch, is an address switch for operation control, using the principle of 0/1 binary code. The DIP switch is mostly used in the program control board to control the conduction and disconnection of the performance circuit of the component. There are two pins on the upper and lower sides of the back corresponding to each key of the DIP switch. When the DIP switch is on the ON side, these two pins are connected, otherwise disconnect. The four keys are independent and unrelated to each other. These elements are mainly used for binary encoding.