There are many types of dip switches, and currently two are widely used. They are both decimal inputs, but their outputs are different. One is BCD code (i.e. binary decimal) output, and the other is decimal output.

The most convenient way to use as a human-machine interface is the dial switch for decimal input/BCD code output. Each dial can represent one decimal number, and you can choose how many BCD code dials to splice together if you need several decimal numbers,

If four BCD dials are spliced together, a four digit decimal input dial group can be obtained. There are 5 contacts behind each BCD dial, where A is the input control line and the other 4 are BCD code output signal lines.

When the dial is turned to different positions, input control line A is connected to one or more of the four BCD code output lines. The BCD code output line connected to it is in the same state as the decimal number indicated by the dial, which conforms to the binary decimal coding relationship.

The principle of decimal output DIP switch is relatively easy to understand. Each dial of this DIP switch also has ten positions from 0 to 9, and each position has a corresponding number display, representing the decimal number input by the dial. There are a total of 11 contacts behind the dial, where A is the input control line and the other 10 are the output signal lines. When the dial is turned to different positions, input control line A is connected to one of the 10 output lines, and can only be connected to one of them.