Hardware Configuration Features; Jumpers And Switches-A General Explanation; Jumpers; Switches - Dell Precision 400 User Manual

Appendix B

Hardware Configuration Features

T
his appendix provides specific information about the
jumpers on your system board and the input/output (I/O)
ports and connectors on the back panel of your computer.
It also provides some basic information on jumpers and
switches, a listing of interrupt request (IRQ) assignments,
and memory maps.
J
umpers and Switches—
A General Explanation
Jumpers and switches provide a convenient and revers-
ible way of reconfiguring the circuitry on a printed circuit
board. When reconfiguring your system, you may need to
change jumper settings on your system board; you may
also need to change jumper and/or switch settings on
expansion cards or drives.

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.
Figure B-1 shows the location and default settings of the
jumper blocks on your system board. See Table B-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
Hardware Configuration Features
rocker switches
B-1