User`s manual

Jumper
A jumper is a kind of switch which uses a plastic cap with a metal
interior to connect (short) two pins. If a jumper needs to be left open,
you should save the cap for future use by covering only one pin of a
jumper. This has no effect on the function of the board while it keeps
the cap handy. The illustration below shows the side and top views of
a three-pin jumper in which pins two and three are shorted.
Side View
Top View
I
Pin 1
Figure 2-6: An Example of Three-Pin Jumper Setting
6 Chapter 2: Setting Up Your System