A series of tiny switches built into circuit boards. The housing for the switches, which has the same shape as a chip, is the DIP.
DIP switches enable you to configure a circuit board for a particular type of computer or application. The installation instructions should tell you how to set the switches. DIP switches are always toggle switches, which means they have two possible positions — on or off. (Instead of on and off, you may see the numbers 1 and 0.)
One of the historic advantages of the Macintosh over the PC was that it allowed you to configure circuit boards by entering software commands instead of setting DIP switches. However, the new Plug & Play standard developed by Microsoft makes DIP switches obsolete for PC expansion cards too.