DIP switch
A DIP switch is a small switch in a DIP (dual in-line package) whose position changes the operating mode of a device. DIP switches help configure computer peripherals, such as hard drives, modems, sound cards, and motherboards. They are used as an alternative to jumpers because they are easier to operate and less likely to get lost. Today, DIP switches are less common because most computers utilize plug and play, so hardware no longer requires manual configuration.
Make sure to disconnect power before changing a DIP switch on any device. Also, before you work inside of a computer, be aware of electrostatic discharge.
Where are DIP switches on my device?
Not all devices, especially newer devices have DIP switches. If you cannot find anything that resembles the above picture, look for jumpers instead of DIP switches.