Jumpers; Switches - Dell OptiPlex GXi Reference And Installation Manual

During an installation procedure, you may be required to
change a jumper setting on the system board and/or a
jumper or switch setting on an expansion card or on a
drive. Jumpers and switches provide a convenient and
reversible way of reconfiguring the circuitry on a printed
circuit board. For information on jumpers and switches,
see the next two subsections, "Jumpers" and "Switches."

Jumpers

Jumpers are small blocks on a circuit
board with two or more pins
emerging from them.
Plastic plugs containing a wire fit
down over the pins. The wire connects
the pins and creates a circuit.
To change a jumper setting, pull the plug
off its pin(s) and carefully fit it down onto
the pin(s) indicated.
CAUTION: Make sure your system is turned off
before you change a jumper setting. Otherwise,
damage to your system or unpredictable results
may occur.
A jumper is referred to as open or unjumpered when the
plug is pushed down over only one pin or if there is no
plug at all. When the plug is pushed down over two pins,
the jumper is referred to as jumpered. The jumper setting
is often shown in text as two numbers, such as 1-2. The
number 1 is printed on the circuit board so that you can
identify each pin number based on the location of pin 1.
5-4 Dell OptiPlex GX i Mini Tower Systems Reference and Installation Guide
Figure 5-6 shows the location and default settings of the
jumper blocks on your system board. See Table 5-1 for
the designations, default settings, and functions of your
system's jumpers.

Switches

Switches control various circuits or functions in your
computer system. The switches you are most likely to
encounter are dual in-line package (DIP) switches, which
are normally packaged in groups of two or more switches
in a plastic case. Two common types of DIP switches are
slide switches and rocker switches (see the following
illustration).
slide switches
Each of these switches has two positions, or settings
(usually on and off). To change the setting of a slide
switch, use a small, pointed object such as a small screw-
driver or a straightened paper clip to slide the switch to
the proper position. To change the setting of a rocker
switch, use the screwdriver or paper clip to press down
on the appropriate side of the switch. In either case, do
not use a pen, pencil, or other object that might leave a
residue on the switch.
rocker switches