A fiber jumper, sometimes called a fiber patch cord is a length of fiber cabling fitted with LC, SC, MTRJ or ST connectors at each end. The LC, a smaller form factor connector, is most commonly used. Fiber jumpers also come in hybrid varieties with one type of connector on one end and another type of connector on the other. Jumpers are used in the same manner as patch cords, to connect end devices or network hardware to the structured cabling system. Fiber patch cords come in either single mode or multimode and should be selected to match the structured cabling system. The only exception to this is mode conditioning patch cords (also known as mode conditioning fiber jumpers) that are required when transmitting gigabit signals over 200m on 62.5 micron multimode fiber. When a fiber channel is tested, it is called a channel test if patch cords are included, but a permanent link test otherwise