<s>
In	O
electronics	O
and	O
particularly	O
computing	O
,	O
a	O
jumper	B-Device
is	O
a	O
short	B-Application
length	O
of	O
conductor	O
used	O
to	O
close	O
,	O
open	O
or	O
bypass	O
part	O
of	O
an	O
electronic	O
circuit	O
.	O
</s>
<s>
They	O
are	O
typically	O
used	O
to	O
set	O
up	O
or	O
configure	O
printed	O
circuit	O
boards	O
,	O
such	O
as	O
the	O
motherboards	B-Device
of	O
computers	O
.	O
</s>
<s>
The	O
process	O
of	O
setting	O
a	O
jumper	B-Device
is	O
often	O
called	O
strapping	O
.	O
</s>
<s>
A	O
strapping	B-Device
option	I-Device
is	O
a	O
hardware	O
configuration	O
setting	O
usually	O
sensed	O
only	O
during	O
power-up	O
or	O
bootstrapping	B-Application
of	O
a	O
device	O
(	O
or	O
even	O
a	O
single	O
chip	O
)	O
.	O
</s>
<s>
Jumper	B-Device
pins	O
(	O
points	O
to	O
be	O
connected	O
by	O
the	O
jumper	B-Device
)	O
are	O
arranged	O
in	O
groups	O
called	O
jumper	B-Device
blocks	I-Device
,	O
each	O
group	O
having	O
at	O
least	O
one	O
pair	O
of	O
contact	O
points	O
.	O
</s>
<s>
An	O
appropriately	O
sized	O
conductive	O
sleeve	O
called	O
a	O
jumper	B-Device
,	O
or	O
more	O
technically	O
,	O
a	O
shunt	B-Device
jumper	I-Device
,	O
is	O
slipped	O
over	O
the	O
pins	O
to	O
complete	O
the	O
circuit	O
.	O
</s>
<s>
A	O
two-pin	O
jumper	B-Device
only	O
allows	O
to	O
choose	O
between	O
two	O
Boolean	B-General_Concept
states	O
,	O
whereas	O
a	O
three-pin	O
jumper	B-Device
allows	O
to	O
select	O
between	O
three	O
states	O
.	O
</s>
<s>
Jumpers	B-Device
must	O
be	O
electrically	O
conducting	O
;	O
they	O
are	O
usually	O
encased	O
in	O
a	O
non-conductive	O
block	O
of	O
plastic	O
for	O
convenience	O
.	O
</s>
<s>
This	O
also	O
avoids	O
the	O
risk	O
that	O
an	O
unshielded	O
jumper	B-Device
will	O
accidentally	O
short	B-Application
out	O
something	O
critical	O
(	O
particularly	O
if	O
it	O
is	O
dropped	O
on	O
a	O
live	O
circuit	O
)	O
.	O
</s>
<s>
Jumper	B-Device
shunts	I-Device
can	O
be	O
categorized	O
by	O
their	O
pitch	O
(	O
uniform	O
distance	O
between	O
pins	O
measured	O
from	O
center	O
to	O
center	O
)	O
.	O
</s>
<s>
When	O
a	O
jumper	B-Device
is	O
placed	O
over	O
two	O
or	O
more	O
jumper	B-Device
pins	O
,	O
an	O
electrical	O
connection	O
is	O
made	O
between	O
them	O
,	O
and	O
the	O
equipment	O
is	O
thus	O
instructed	O
to	O
activate	O
certain	O
settings	O
accordingly	O
.	O
</s>
<s>
For	O
example	O
,	O
with	O
older	O
PC	O
systems	O
,	O
CPU	B-General_Concept
speed	O
and	O
voltage	O
settings	O
were	O
often	O
made	O
by	O
setting	O
jumpers	B-Device
.	O
</s>
<s>
Some	O
documentation	O
may	O
refer	O
to	O
setting	O
the	O
jumpers	B-Device
to	O
on	O
,	O
off	O
,	O
closed	O
,	O
or	O
open	O
.	O
</s>
<s>
When	O
a	O
jumper	B-Device
is	O
on	O
or	O
covering	O
at	O
least	O
two	O
pins	O
it	O
is	O
a	O
closed	B-Device
jumper	I-Device
,	O
when	O
a	O
jumper	B-Device
is	O
off	O
,	O
is	O
covering	O
only	O
one	O
pin	O
,	O
or	O
the	O
pins	O
have	O
no	O
jumper	B-Device
it	O
is	O
an	O
open	B-Device
jumper	I-Device
.	O
</s>
<s>
Jumperless	B-Device
designs	O
have	O
the	O
advantage	O
that	O
they	O
are	O
usually	O
fast	O
and	O
easy	O
to	O
set	O
up	O
,	O
often	O
require	O
little	O
technical	O
knowledge	O
,	O
and	O
can	O
be	O
adjusted	O
without	O
having	O
physical	O
access	O
to	O
the	O
circuit	O
board	O
.	O
</s>
<s>
With	O
PCs	O
,	O
the	O
most	O
common	O
use	O
of	O
jumpers	B-Device
is	O
in	O
setting	O
the	O
operating	O
mode	O
for	O
ATA	B-Protocol
drives	I-Protocol
(	O
master	B-Operating_System
,	I-Operating_System
slave	I-Operating_System
,	O
or	O
cable	O
select	O
)	O
,	O
though	O
this	O
use	O
declined	O
with	O
the	O
rise	O
of	O
SATA	O
drives	O
and	O
Plug	B-Device
and	I-Device
Play	I-Device
devices	O
.	O
</s>
<s>
Jumpers	B-Device
have	O
been	O
used	O
since	O
the	O
beginning	O
of	O
printed	O
circuit	O
boards	O
.	O
</s>
<s>
Some	O
printed	O
wiring	O
assemblies	O
,	O
particularly	O
those	O
using	O
single-layer	O
circuit	O
boards	O
,	O
include	O
short	B-Application
lengths	O
of	O
wire	O
soldered	O
between	O
pairs	O
of	O
points	O
.	O
</s>
<s>
These	O
wires	O
are	O
called	O
wire	B-Device
bridges	I-Device
or	O
jumpers	B-Device
,	O
but	O
unlike	O
jumpers	B-Device
used	O
for	O
configuration	O
settings	O
,	O
they	O
are	O
intended	O
to	O
permanently	O
connect	O
the	O
points	O
in	O
question	O
.	O
</s>
<s>
Jumpers	B-Device
setting	O
configuration	O
options	O
not	O
normally	O
meant	O
to	O
be	O
user-configurable	O
can	O
also	O
be	O
implemented	O
as	O
solder	B-Device
jumpers	I-Device
,	O
typically	O
two	O
(	O
or	O
more	O
)	O
pads	O
positioned	O
closely	O
together	O
or	O
even	O
with	O
interwoven	O
shapes	O
.	O
</s>
<s>
If	O
the	O
closed	O
state	O
is	O
the	O
default	O
state	O
,	O
the	O
PCB	O
designer	O
can	O
superimpose	O
a	O
thin	O
trace	O
,	O
which	O
would	O
be	O
cut	O
(	O
with	O
a	O
knife	O
)	O
to	O
open	O
the	O
jumper	B-Device
.	O
</s>
