This is a small metal connector that acts as an on/off switch and is used to alter hardware configurations. A jumper is typically made of two wires and a small piece of metal. When the wires are connected by the metal piece, the jumper is turned on, completing the circuit. When the wires are disconnected, the jumper is turned off. Multiple jumpers, referred to collectively as a jumper block, are often used to tell the computer how a certain device, such as a hard drive or a modem, is configured. They can be found on motherboards, sound cards, graphics cards, I/O cards, CD-ROM interface boards, modems, and hard drive controller boards, and others.
Manually setting jumpers can be a confusing process, so most hardware usually comes with the necessary jumpers preset. If they are not preset, there should be documentation with a clear diagram of the jumper settings included with the hardware. Fortunately, a lot of plug-and-play equipment available today does not require any jumpers. These devices can be configured through a user-friendly interface on your computer.