<s>
A	O
computer	B-Device
keyboard	I-Device
is	O
a	O
peripheral	O
input	B-Device
device	I-Device
modeled	O
after	O
the	O
typewriter	O
keyboard	B-Device
which	O
uses	O
an	O
arrangement	O
of	O
buttons	O
or	O
keys	O
to	O
act	O
as	O
mechanical	O
levers	O
or	O
electronic	B-Device
switches	I-Device
.	O
</s>
<s>
Replacing	O
early	O
punched	B-Architecture
cards	I-Architecture
and	O
paper	O
tape	O
technology	O
,	O
interaction	O
via	O
teleprinter-style	O
keyboards	B-Device
have	O
been	O
the	O
main	O
input	B-Device
method	I-Device
for	O
computers	O
since	O
the	O
1970s	O
,	O
supplemented	O
by	O
the	O
computer	B-Device
mouse	I-Device
since	O
the	O
1980s	O
.	O
</s>
<s>
Keyboard	B-Device
keys	O
(	O
buttons	O
)	O
typically	O
have	O
a	O
set	O
of	O
characters	O
engraved	B-Application
or	O
printed	O
on	O
them	O
,	O
and	O
each	O
press	O
of	O
a	O
key	O
typically	O
corresponds	O
to	O
a	O
single	O
written	O
symbol	O
.	O
</s>
<s>
While	O
most	O
keys	O
produce	O
characters	O
(	O
letters	O
,	O
numbers	O
or	O
symbols	O
)	O
,	O
other	O
keys	O
(	O
such	O
as	O
the	O
escape	B-Device
key	I-Device
)	O
can	O
prompt	O
the	O
computer	O
to	O
execute	O
system	O
commands	O
.	O
</s>
<s>
In	O
normal	O
usage	O
,	O
the	O
keyboard	B-Device
is	O
used	O
as	O
a	O
text	B-Device
entry	I-Device
interface	I-Device
for	O
typing	B-Application
text	O
,	O
numbers	O
,	O
and	O
symbols	O
into	O
application	B-Application
software	I-Application
such	O
as	O
a	O
word	B-General_Concept
processor	I-General_Concept
,	O
web	B-Application
browser	I-Application
or	O
social	O
media	O
app	O
.	O
</s>
<s>
Touchscreens	B-Device
use	O
virtual	B-Device
keyboards	I-Device
.	O
</s>
<s>
While	O
typewriters	O
are	O
the	O
definitive	O
ancestor	O
of	O
all	O
key-based	O
text	B-Device
entry	I-Device
devices	I-Device
,	O
the	O
computer	B-Device
keyboard	I-Device
as	O
a	O
device	O
for	O
electromechanical	O
data	O
entry	O
and	O
communication	O
derives	O
largely	O
from	O
the	O
utility	O
of	O
two	O
devices	O
:	O
teleprinters	O
(	O
or	O
teletypes	O
)	O
and	O
keypunches	B-Device
.	O
</s>
<s>
It	O
was	O
through	O
such	O
devices	O
that	O
modern	O
computer	B-Device
keyboards	I-Device
inherited	O
their	O
layouts	O
.	O
</s>
<s>
As	O
early	O
as	O
the	O
1870s	O
,	O
teleprinter-like	O
devices	O
were	O
used	O
to	O
simultaneously	O
type	O
and	O
transmit	O
stock	O
market	O
text	O
data	O
from	O
the	O
keyboard	B-Device
across	O
telegraph	O
lines	O
to	O
stock	O
ticker	O
machines	O
to	O
be	O
immediately	O
copied	O
and	O
displayed	O
onto	O
ticker	O
tape	O
.	O
</s>
<s>
Earlier	O
,	O
Herman	O
Hollerith	O
developed	O
the	O
first	O
keypunch	B-Device
devices	O
,	O
which	O
soon	O
evolved	O
to	O
include	O
keys	O
for	O
text	O
and	O
number	O
entry	O
akin	O
to	O
normal	O
typewriters	O
by	O
the	O
1930s	O
.	O
</s>
<s>
The	O
keyboard	B-Device
on	O
the	O
teleprinter	O
played	O
a	O
strong	O
role	O
in	O
point-to-point	O
and	O
point-to-multipoint	O
communication	O
for	O
most	O
of	O
the	O
20th	O
century	O
,	O
while	O
the	O
keyboard	B-Device
on	O
the	O
keypunch	B-Device
device	O
played	O
a	O
strong	O
role	O
in	O
data	O
entry	O
and	O
storage	O
for	O
just	O
as	O
long	O
.	O
</s>
<s>
The	O
development	O
of	O
the	O
earliest	O
computers	O
incorporated	O
electric	O
typewriter	O
keyboards	B-Device
:	O
the	O
development	O
of	O
the	O
ENIAC	B-Device
computer	I-Device
incorporated	O
a	O
keypunch	B-Device
device	O
as	O
both	O
the	O
input	O
and	O
paper-based	O
output	O
device	O
,	O
while	O
the	O
BINAC	B-Device
computer	O
also	O
made	O
use	O
of	O
an	O
electromechanically	O
controlled	O
typewriter	O
for	O
both	O
data	O
entry	O
onto	O
magnetic	O
tape	O
(	O
instead	O
of	O
paper	O
)	O
and	O
data	O
output	O
.	O
</s>
<s>
The	O
keyboard	B-Device
remained	O
the	O
primary	O
,	O
most	O
integrated	O
computer	O
peripheral	O
well	O
into	O
the	O
era	O
of	O
personal	O
computing	O
until	O
the	O
introduction	O
of	O
the	O
mouse	O
as	O
a	O
consumer	O
device	O
in	O
1984	O
.	O
</s>
<s>
By	O
this	O
time	O
,	O
text-only	O
user	O
interfaces	O
with	O
sparse	O
graphics	O
gave	O
way	O
to	O
comparatively	B-Application
graphics-rich	I-Application
icons	I-Application
on	I-Application
screen	I-Application
.	O
</s>
<s>
However	O
,	O
keyboards	B-Device
remain	O
central	O
to	O
human-computer	O
interaction	O
to	O
the	O
present	O
though	O
mobile	O
personal	O
computing	O
devices	O
such	O
as	O
smartphones	B-Application
and	O
tablets	B-Device
use	O
a	O
virtual	B-Device
keyboard	I-Device
.	O
</s>
<s>
Different	O
types	O
of	O
keyboards	B-Device
are	O
available	O
and	O
each	O
is	O
designed	O
with	O
a	O
focus	O
on	O
specific	O
features	O
that	O
suit	O
particular	O
needs	O
.	O
</s>
<s>
Today	O
,	O
most	O
full-size	O
keyboards	B-Device
use	O
one	O
of	O
three	O
different	O
mechanical	O
layouts	O
,	O
usually	O
referred	O
to	O
as	O
simply	O
ISO	O
(	O
ISO/IEC	O
9995-2	O
)	O
,	O
ANSI	O
(	O
ANSI-INCITS	O
154-1988	O
)	O
,	O
and	O
JIS	O
(	O
JIS	O
X	O
6002-1980	O
)	O
,	O
referring	O
roughly	O
to	O
the	O
organizations	O
issuing	O
the	O
relevant	O
worldwide	O
,	O
United	O
States	O
,	O
and	O
Japanese	O
standards	O
,	O
respectively	O
.	O
</s>
<s>
ANSI	O
standard	O
alphanumeric	O
keyboards	B-Device
have	O
keys	O
that	O
are	O
on	O
three-quarter	O
inch	O
centers	O
(	O
)	O
,	O
and	O
have	O
a	O
key	O
travel	O
of	O
at	O
least	O
.	O
</s>
<s>
Modern	O
keyboard	B-Device
models	O
contain	O
a	O
set	O
number	O
of	O
total	O
keys	O
according	O
to	O
their	O
given	O
standard	O
,	O
described	O
as	O
101	O
,	O
104	O
,	O
105	O
,	O
etc	O
.	O
</s>
<s>
and	O
sold	O
as	O
"	O
Full-size	O
"	O
keyboards	B-Device
.	O
</s>
<s>
Modern	O
keyboards	B-Device
matching	O
US	O
conventions	O
typically	O
have	O
104	O
keys	O
while	O
the	O
105	O
key	O
layout	O
is	O
the	O
norm	O
in	O
the	O
rest	O
of	O
the	O
world	O
.	O
</s>
<s>
The	O
most	O
common	O
choice	O
is	O
to	O
not	O
include	O
the	O
numpad	B-Device
,	O
which	O
can	O
usually	O
be	O
fully	O
replaced	O
by	O
the	O
alphanumeric	O
section	O
;	O
such	O
designs	O
are	O
referred	O
to	O
as	O
"	O
tenkeyless	O
"	O
.	O
</s>
<s>
Laptops	B-Device
and	O
wireless	O
peripherals	O
often	O
lack	O
duplicate	O
keys	O
and	O
ones	O
seldom	O
used	O
.	O
</s>
<s>
Function	O
-	O
and	O
arrow	B-Device
keys	I-Device
are	O
nearly	O
always	O
present	O
.	O
</s>
<s>
Another	O
factor	O
determining	O
the	O
size	O
of	O
a	O
keyboard	B-Device
is	O
the	O
size	O
and	O
spacing	O
of	O
the	O
keys	O
.	O
</s>
<s>
Desktop	O
computer	B-Device
keyboards	I-Device
include	O
alphabetic	O
characters	O
and	O
numerals	O
(	O
and	O
usually	O
additionally	O
a	O
numeric	B-Device
keypad	I-Device
)	O
,	O
typographical	O
symbols	O
and	O
punctuation	O
marks	O
,	O
one	O
or	O
more	O
currency	O
symbols	O
and	O
other	O
special	O
characters	O
,	O
diacritics	O
and	O
a	O
variety	O
of	O
function	B-Application
keys	I-Application
.	O
</s>
<s>
The	O
repertoire	O
of	O
glyphs	B-Application
engraved	B-Application
on	O
the	O
keys	O
of	O
a	O
keyboard	B-Device
accords	O
with	O
national	O
conventions	O
and	O
language	O
needs	O
.	O
</s>
<s>
Computer	B-Device
keyboards	I-Device
are	O
similar	O
to	O
electric-typewriter	O
keyboards	B-Device
but	O
contain	O
additional	O
keys	O
,	O
such	O
as	O
the	O
command	B-Device
key	I-Device
or	O
Windows	B-Device
keys	I-Device
.	O
</s>
<s>
Keyboards	B-Device
on	O
laptops	B-Device
and	O
notebook	B-Device
computers	I-Device
usually	O
have	O
a	O
shorter	O
travel	O
distance	O
for	O
the	O
keystroke	O
,	O
shorter	O
over	O
travel	O
distance	O
,	O
and	O
a	O
reduced	O
set	O
of	O
keys	O
.	O
</s>
<s>
They	O
may	O
not	O
have	O
a	O
numeric	B-Device
keypad	I-Device
,	O
and	O
the	O
function	B-Application
keys	I-Application
may	O
be	O
placed	O
in	O
locations	O
that	O
differ	O
from	O
their	O
placement	O
on	O
a	O
standard	O
,	O
full-sized	O
keyboard	B-Device
.	O
</s>
<s>
The	O
switch	O
mechanism	O
for	O
a	O
laptop	B-Device
keyboard	B-Device
is	O
more	O
likely	O
to	O
be	O
a	O
scissor	O
switch	O
than	O
a	O
rubber	O
dome	O
;	O
this	O
is	O
opposite	O
the	O
trend	O
for	O
full-size	O
keyboards	B-Device
.	O
</s>
<s>
Flexible	O
keyboards	B-Device
are	O
a	O
junction	O
between	O
normal	O
type	O
and	O
laptop	B-Device
type	O
keyboards	B-Device
:	O
normal	O
from	O
the	O
full	O
arrangement	O
of	O
keys	O
,	O
and	O
laptop	B-Device
from	O
the	O
short	O
key	O
distance	O
.	O
</s>
<s>
Additionally	O
,	O
the	O
flexibility	O
allows	O
the	O
user	O
to	O
fold/roll	O
the	O
keyboard	B-Device
for	O
better	O
storage	O
and	O
transfer	O
.	O
</s>
<s>
However	O
,	O
for	O
typing	B-Application
the	O
keyboard	B-Device
must	O
be	O
resting	O
on	O
a	O
hard	O
surface	O
.	O
</s>
<s>
The	O
vast	O
majority	O
of	O
flexible	O
keyboards	B-Device
in	O
the	O
market	O
are	O
made	O
from	O
silicone	O
;	O
this	O
material	O
makes	O
them	O
water	O
-	O
and	O
dust-proof	O
.	O
</s>
<s>
This	O
is	O
useful	O
in	O
hospitals	O
,	O
where	O
keyboards	B-Device
are	O
subjected	O
to	O
frequent	O
washing	O
,	O
</s>
<s>
Handheld	O
ergonomic	B-Device
keyboards	I-Device
are	O
designed	O
to	O
be	O
held	O
like	O
a	O
game	O
controller	O
,	O
and	O
can	O
be	O
used	O
as	O
such	O
,	O
instead	O
of	O
laid	O
out	O
flat	O
on	O
top	O
of	O
a	O
table	O
surface	O
.	O
</s>
<s>
Typically	O
handheld	O
keyboards	B-Device
hold	O
all	O
the	O
alphanumeric	O
keys	O
and	O
symbols	O
that	O
a	O
standard	O
keyboard	B-Device
would	O
have	O
,	O
yet	O
only	O
be	O
accessed	O
by	O
pressing	O
two	O
sets	O
of	O
keys	O
at	O
once	O
;	O
one	O
acting	O
as	O
a	O
function	B-Application
key	I-Application
similar	O
to	O
a	O
'	O
Shift	O
 '	O
key	O
that	O
would	O
allow	O
for	O
capital	O
letters	O
on	O
a	O
standard	O
keyboard	B-Device
.	O
</s>
<s>
Handheld	O
keyboards	B-Device
allow	O
the	O
user	O
the	O
ability	O
to	O
move	O
around	O
a	O
room	O
or	O
to	O
lean	O
back	O
on	O
a	O
chair	O
while	O
also	O
being	O
able	O
to	O
type	O
in	O
front	O
or	O
away	O
from	O
the	O
computer	O
.	O
</s>
<s>
Some	O
variations	O
of	O
handheld	O
ergonomic	B-Device
keyboards	I-Device
also	O
include	O
a	O
trackball	B-Device
mouse	I-Device
that	O
allow	O
mouse	O
movement	O
and	O
typing	B-Application
included	O
in	O
one	O
handheld	O
device	O
.	O
</s>
<s>
Smaller	O
external	O
keyboards	B-Device
have	O
been	O
introduced	O
for	O
devices	O
without	O
a	O
built-in	O
keyboard	B-Device
,	O
such	O
as	O
PDAs	B-Application
,	O
and	O
smartphones	B-Application
.	O
</s>
<s>
Small	O
keyboards	B-Device
are	O
also	O
useful	O
where	O
there	O
is	O
a	O
limited	O
workspace	O
.	O
</s>
<s>
A	O
thumb	B-Device
keyboard	I-Device
(	O
thumb	O
board	O
)	O
is	O
used	O
in	O
some	O
personal	B-Application
digital	I-Application
assistants	I-Application
such	O
as	O
the	O
Palm	O
Treo	O
and	O
BlackBerry	B-Operating_System
and	O
some	O
Ultra-Mobile	B-Device
PCs	I-Device
such	O
as	O
the	O
OQO	O
.	O
</s>
<s>
Numeric	O
keyboards	B-Device
contain	O
only	O
numbers	O
,	O
mathematical	O
symbols	O
for	O
addition	O
,	O
subtraction	O
,	O
multiplication	O
,	O
and	O
division	O
,	O
a	O
decimal	O
point	O
,	O
and	O
several	O
function	B-Application
keys	I-Application
.	O
</s>
<s>
They	O
are	O
often	O
used	O
to	O
facilitate	O
data	O
entry	O
with	O
smaller	O
keyboards	B-Device
that	O
do	O
not	O
have	O
a	O
numeric	B-Device
keypad	I-Device
,	O
commonly	O
those	O
of	O
laptop	B-Device
computers	I-Device
.	O
</s>
<s>
These	O
keys	O
are	O
collectively	O
known	O
as	O
a	O
numeric	B-Device
pad	I-Device
,	O
numeric	O
keys	O
,	O
or	O
a	O
numeric	B-Device
keypad	I-Device
,	O
and	O
it	O
can	O
consist	O
of	O
the	O
following	O
types	O
of	O
keys	O
:	O
Arithmetic	O
operators	O
,	O
numbers	O
,	O
arrow	B-Device
keys	I-Device
,	O
Navigation	O
keys	O
,	O
Num	B-Device
Lock	I-Device
and	O
Enter	B-Device
key	I-Device
.	O
</s>
<s>
Multifunctional	O
keyboards	B-Device
provide	O
additional	O
function	O
beyond	O
the	O
standard	O
keyboard	B-Device
.	O
</s>
<s>
Many	O
are	O
programmable	O
,	O
configurable	O
computer	B-Device
keyboards	I-Device
and	O
some	O
control	B-Device
multiple	O
PCs	O
,	O
workstations	O
and	O
other	O
information	O
sources	O
,	O
usually	O
in	O
multi-screen	O
work	O
environments	O
.	O
</s>
<s>
Users	O
have	O
additional	O
key	O
functions	O
as	O
well	O
as	O
the	O
standard	O
functions	O
and	O
can	O
typically	O
use	O
a	O
single	O
keyboard	B-Device
and	O
mouse	O
to	O
access	O
multiple	O
sources	O
.	O
</s>
<s>
Multifunctional	O
keyboards	B-Device
may	O
feature	O
customised	O
keypads	B-Device
,	O
fully	O
programmable	O
function	O
or	O
soft	O
keys	O
for	O
macros/pre	O
-sets	O
,	O
biometric	O
or	O
smart	O
card	O
readers	O
,	O
trackballs	B-Device
,	O
etc	O
.	O
</s>
<s>
New	O
generation	O
multifunctional	O
keyboards	B-Device
feature	O
a	O
touchscreen	B-Device
display	O
to	O
stream	O
video	O
,	O
control	B-Device
audio	O
visual	O
media	O
and	O
alarms	O
,	O
execute	O
application	B-Application
inputs	O
,	O
configure	O
individual	O
desktop	O
environments	O
,	O
etc	O
.	O
</s>
<s>
Multifunctional	O
keyboards	B-Device
may	O
also	O
permit	O
users	O
to	O
share	O
access	O
to	O
PCs	O
and	O
other	O
information	O
sources	O
.	O
</s>
<s>
Multiple	O
interfaces	O
(	O
serial	O
,	O
USB	B-Protocol
,	O
audio	O
,	O
Ethernet	O
,	O
etc	O
.	O
)	O
</s>
<s>
Some	O
multifunctional	O
keyboards	B-Device
are	O
also	O
used	O
to	O
directly	O
and	O
intuitively	O
control	B-Device
video	O
walls	O
.	O
</s>
<s>
Common	O
environments	O
for	O
multifunctional	O
keyboards	B-Device
are	O
complex	O
,	O
high-performance	O
workplaces	O
for	O
financial	O
traders	O
and	O
control	B-Device
room	O
operators	O
(	O
emergency	O
services	O
,	O
security	O
,	O
air	O
traffic	O
management	O
;	O
industry	O
,	O
utilities	O
management	O
,	O
etc	O
.	O
</s>
<s>
While	O
other	O
keyboards	B-Device
generally	O
associate	O
one	O
action	O
with	O
each	O
key	O
,	O
chorded	O
keyboards	B-Device
associate	O
actions	O
with	O
combinations	O
of	O
key	O
presses	O
.	O
</s>
<s>
Since	O
there	O
are	O
many	O
combinations	O
available	O
,	O
chorded	O
keyboards	B-Device
can	O
effectively	O
produce	O
more	O
actions	O
on	O
a	O
board	O
with	O
fewer	O
keys	O
.	O
</s>
<s>
Court	O
reporters	O
 '	O
stenotype	O
machines	O
use	O
chorded	O
keyboards	B-Device
to	O
enable	O
them	O
to	O
enter	O
text	O
much	O
faster	O
by	O
typing	B-Application
a	O
syllable	O
with	O
each	O
stroke	O
instead	O
of	O
one	O
letter	O
at	O
a	O
time	O
.	O
</s>
<s>
The	O
fastest	O
typists	O
(	O
as	O
of	O
2007	O
)	O
use	O
a	O
stenograph	O
,	O
a	O
kind	O
of	O
chorded	O
keyboard	B-Device
used	O
by	O
most	O
court	O
reporters	O
and	O
closed-caption	O
reporters	O
.	O
</s>
<s>
Some	O
chorded	O
keyboards	B-Device
are	O
also	O
made	O
for	O
use	O
in	O
situations	O
where	O
fewer	O
keys	O
are	O
preferable	O
,	O
such	O
as	O
on	O
devices	O
that	O
can	O
be	O
used	O
with	O
only	O
one	O
hand	O
,	O
and	O
on	O
small	O
mobile	O
devices	O
that	O
do	O
n't	O
have	O
room	O
for	O
larger	O
keyboards	B-Device
.	O
</s>
<s>
Chorded	O
keyboards	B-Device
are	O
less	O
desirable	O
in	O
many	O
cases	O
because	O
it	O
usually	O
takes	O
practice	O
and	O
memorization	O
of	O
the	O
combinations	O
to	O
become	O
proficient	O
.	O
</s>
<s>
Virtual	B-Device
keyboards	I-Device
,	O
sometimes	O
called	O
on-screen	B-Device
keyboards	I-Device
(	O
rarely	O
software	B-Device
keyboards	I-Device
)	O
,	O
consist	O
of	O
computer	O
programs	O
that	O
display	O
an	O
image	O
of	O
a	O
keyboard	B-Device
on	O
the	O
screen	O
.	O
</s>
<s>
Another	O
input	B-Device
device	I-Device
such	O
as	O
a	O
mouse	O
or	O
a	O
touchscreen	B-Device
can	O
be	O
used	O
to	O
operate	O
each	O
virtual	O
key	O
to	O
enter	O
text	O
.	O
</s>
<s>
Virtual	B-Device
keyboards	I-Device
have	O
become	O
very	O
popular	O
in	O
touchscreen	B-Device
enabled	O
cell	O
phones	O
due	O
to	O
the	O
additional	O
cost	O
and	O
space	O
requirements	O
of	O
other	O
types	O
of	O
hardware	O
keyboards	B-Device
.	O
</s>
<s>
Microsoft	O
Windows	B-Device
,	O
Mac	O
OS	O
X	O
,	O
and	O
some	O
varieties	O
of	O
Linux	B-Operating_System
include	O
on-screen	B-Device
keyboards	I-Device
that	O
can	O
be	O
controlled	O
with	O
the	O
mouse	O
.	O
</s>
<s>
Projection	B-Device
keyboards	I-Device
project	O
an	O
image	O
of	O
keys	O
,	O
usually	O
with	O
a	O
laser	O
,	O
onto	O
a	O
flat	O
surface	O
.	O
</s>
<s>
The	O
device	O
then	O
uses	O
a	O
camera	O
or	O
infrared	O
sensor	O
to	O
"	O
watch	O
"	O
where	O
the	O
user	O
's	O
fingers	O
move	O
,	O
and	O
will	O
count	O
a	O
key	O
as	O
being	O
pressed	O
when	O
it	O
"	O
sees	O
"	O
the	O
user	O
's	O
finger	B-Device
touch	I-Device
the	O
projected	O
image	O
.	O
</s>
<s>
Projection	B-Device
keyboards	I-Device
can	O
simulate	O
a	O
full	O
size	O
keyboard	B-Device
from	O
a	O
very	O
small	O
projector	O
.	O
</s>
<s>
Users	O
of	O
projected	O
keyboards	B-Device
often	O
experience	O
increased	O
discomfort	O
in	O
their	O
fingertips	O
because	O
of	O
the	O
lack	O
of	O
"	O
give	O
"	O
when	O
typing	B-Application
.	O
</s>
<s>
Most	O
projection	B-Device
keyboards	I-Device
are	O
made	O
for	O
use	O
with	O
PDAs	B-Application
and	O
smartphones	B-Application
due	O
to	O
their	O
small	O
form	O
factor	O
.	O
</s>
<s>
Also	O
known	O
as	O
photo-optical	O
keyboard	B-Device
,	O
light	O
responsive	O
keyboard	B-Device
,	O
photo-electric	O
keyboard	B-Device
and	O
optical	O
key	O
actuation	O
detection	O
technology	O
.	O
</s>
<s>
An	O
optical	O
keyboard	B-Device
technology	O
utilizes	O
LEDs	O
and	O
photo	B-Algorithm
sensors	I-Algorithm
to	O
optically	O
detect	O
actuated	O
keys	O
.	O
</s>
<s>
The	O
light	O
is	O
directed	O
from	O
side	O
to	O
side	O
of	O
the	O
keyboard	B-Device
interior	O
and	O
it	O
can	O
only	O
be	O
blocked	O
by	O
the	O
actuated	O
keys	O
.	O
</s>
<s>
Most	O
optical	O
keyboards	B-Device
require	O
at	O
least	O
2	O
beams	O
(	O
most	O
commonly	O
vertical	O
beam	O
and	O
horizontal	O
beam	O
)	O
to	O
determine	O
the	O
actuated	O
key	O
.	O
</s>
<s>
Some	O
optical	O
keyboards	B-Device
use	O
a	O
special	O
key	O
structure	O
that	O
blocks	O
the	O
light	O
in	O
a	O
certain	O
pattern	O
,	O
allowing	O
only	O
one	O
beam	O
per	O
row	O
of	O
keys	O
(	O
most	O
commonly	O
horizontal	O
beam	O
)	O
.	O
</s>
<s>
Alphabetical	O
,	O
numeric	O
,	O
and	O
punctuation	O
keys	O
are	O
used	O
in	O
the	O
same	O
fashion	O
as	O
a	O
typewriter	O
keyboard	B-Device
to	O
enter	O
their	O
respective	O
symbol	O
into	O
a	O
word	O
processing	O
program	O
,	O
text	O
editor	O
,	O
data	O
spreadsheet	O
,	O
or	O
other	O
program	O
.	O
</s>
<s>
Many	O
of	O
these	O
keys	O
will	O
produce	O
different	O
symbols	O
when	O
modifier	B-Device
keys	I-Device
or	O
shift	B-Device
keys	I-Device
are	O
pressed	O
.	O
</s>
<s>
The	O
alphabetic	O
characters	O
become	O
uppercase	O
when	O
the	O
shift	B-Device
key	I-Device
or	O
Caps	B-Device
Lock	I-Device
key	I-Device
is	O
depressed	O
.	O
</s>
<s>
The	O
numeric	O
characters	O
become	O
symbols	O
or	O
punctuation	O
marks	O
when	O
the	O
shift	B-Device
key	I-Device
is	O
depressed	O
.	O
</s>
<s>
The	O
alphabetical	O
,	O
numeric	O
,	O
and	O
punctuation	O
keys	O
can	O
also	O
have	O
other	O
functions	O
when	O
they	O
are	O
pressed	O
at	O
the	O
same	O
time	O
as	O
some	O
modifier	B-Device
keys	I-Device
.	O
</s>
<s>
The	O
Space	B-Device
bar	I-Device
is	O
a	O
horizontal	O
bar	O
in	O
the	O
lowermost	O
row	O
,	O
which	O
is	O
significantly	O
wider	O
than	O
other	O
keys	O
.	O
</s>
<s>
Its	O
main	O
purpose	O
is	O
to	O
enter	O
the	O
space	O
between	O
words	O
during	O
typing	B-Application
.	O
</s>
<s>
Depending	O
on	O
the	O
operating	B-General_Concept
system	I-General_Concept
,	O
when	O
the	O
space	B-Device
bar	I-Device
is	O
used	O
with	O
a	O
modifier	B-Device
key	I-Device
such	O
as	O
the	O
control	B-Device
key	I-Device
,	O
it	O
may	O
have	O
functions	O
such	O
as	O
resizing	O
or	O
closing	O
the	O
current	O
window	O
,	O
half-spacing	O
,	O
or	O
backspacing	O
.	O
</s>
<s>
In	O
computer	O
games	O
and	O
other	O
applications	O
the	O
key	O
has	O
myriad	O
uses	O
in	O
addition	O
to	O
its	O
normal	O
purpose	O
in	O
typing	B-Application
,	O
such	O
as	O
jumping	O
and	O
adding	O
marks	O
to	O
check	O
boxes	O
.	O
</s>
<s>
In	O
certain	O
programs	O
for	O
playback	O
of	O
digital	O
video	O
,	O
the	O
space	B-Device
bar	I-Device
is	O
used	O
for	O
pausing	O
and	O
resuming	O
the	O
playback	O
.	O
</s>
<s>
Modifier	B-Device
keys	I-Device
are	O
special	O
keys	O
that	O
modify	O
the	O
normal	O
action	O
of	O
another	O
key	O
,	O
when	O
the	O
two	O
are	O
pressed	O
in	O
combination	O
.	O
</s>
<s>
For	O
example	O
,	O
in	O
Microsoft	O
Windows	B-Device
will	O
close	O
the	O
program	O
in	O
an	O
active	O
window	O
.	O
</s>
<s>
By	O
themselves	O
,	O
modifier	B-Device
keys	I-Device
usually	O
do	O
nothing	O
.	O
</s>
<s>
The	O
most	O
widely	O
used	O
modifier	B-Device
keys	I-Device
include	O
the	O
Control	B-Device
key	I-Device
,	O
Shift	B-Device
key	I-Device
and	O
the	O
Alt	B-Device
key	I-Device
.	O
</s>
<s>
The	O
AltGr	B-Device
key	I-Device
is	O
used	O
to	O
access	O
additional	O
symbols	O
for	O
keys	O
that	O
have	O
three	O
symbols	O
printed	O
on	O
them	O
.	O
</s>
<s>
On	O
the	O
Macintosh	O
and	O
Apple	O
keyboards	B-Device
,	O
the	O
modifier	B-Device
keys	I-Device
are	O
the	O
Option	B-Device
key	I-Device
and	O
Command	B-Device
key	I-Device
,	O
respectively	O
.	O
</s>
<s>
On	O
Sun	O
Microsystems	O
and	O
Lisp	B-Operating_System
machine	I-Operating_System
keyboards	B-Device
,	O
the	O
Meta	B-Device
key	I-Device
is	O
used	O
as	O
a	O
modifier	O
and	O
for	O
Windows	B-Device
keyboards	B-Device
,	O
there	O
is	O
a	O
Windows	B-Device
key	I-Device
.	O
</s>
<s>
Compact	O
keyboard	B-Device
layouts	O
often	O
use	O
a	O
Fn	B-Device
key	I-Device
.	O
</s>
<s>
"	O
Dead	B-Device
keys	I-Device
"	O
allow	O
placement	O
of	O
a	O
diacritic	O
mark	O
,	O
such	O
as	O
an	O
accent	O
,	O
on	O
the	O
following	O
letter	O
(	O
e.g.	O
,	O
the	O
Compose	B-Device
key	I-Device
)	O
.	O
</s>
<s>
In	O
word	O
processing	O
applications	O
,	O
pressing	O
the	O
enter	B-Device
key	I-Device
ends	O
a	O
paragraph	O
and	O
starts	O
a	O
new	O
one	O
.	O
</s>
<s>
Navigation	O
keys	O
or	O
cursor	B-Device
keys	I-Device
include	O
a	O
variety	O
of	O
keys	O
which	O
move	O
the	O
cursor	O
to	O
different	O
positions	O
on	O
the	O
screen	O
.	O
</s>
<s>
Arrow	B-Device
keys	I-Device
are	O
programmed	O
to	O
move	O
the	O
cursor	O
in	O
a	O
specified	O
direction	O
;	O
page	B-Device
scroll	I-Device
keys	I-Device
,	O
such	O
as	O
the	O
Page	B-Device
Up	I-Device
and	I-Device
Page	I-Device
Down	I-Device
keys	I-Device
,	O
scroll	O
the	O
page	B-Device
up	I-Device
and	O
down	O
.	O
</s>
<s>
The	O
Home	B-Device
key	I-Device
is	O
used	O
to	O
return	O
the	O
cursor	O
to	O
the	O
beginning	O
of	O
the	O
line	O
where	O
the	O
cursor	O
is	O
located	O
;	O
the	O
End	B-Device
key	I-Device
puts	O
the	O
cursor	O
at	O
the	O
end	O
of	O
the	O
line	O
.	O
</s>
<s>
The	O
Insert	B-Device
key	I-Device
is	O
mainly	O
used	O
to	O
switch	O
between	O
overtype	B-Device
mode	I-Device
,	O
in	O
which	O
the	O
cursor	O
overwrites	O
any	O
text	O
that	O
is	O
present	O
on	O
and	O
after	O
its	O
current	O
location	O
,	O
and	O
insert	B-Device
mode	I-Device
,	O
where	O
the	O
cursor	O
inserts	B-Device
a	O
character	O
at	O
its	O
current	O
position	O
,	O
forcing	O
all	O
characters	O
past	O
it	O
one	O
position	O
further	O
.	O
</s>
<s>
The	O
Delete	B-Device
key	I-Device
discards	O
the	O
character	O
ahead	O
of	O
the	O
cursor	O
's	O
position	O
,	O
moving	O
all	O
following	O
characters	O
one	O
position	O
"	O
back	O
"	O
towards	O
the	O
freed	O
place	O
.	O
</s>
<s>
On	O
many	O
notebook	B-Device
computer	I-Device
keyboards	B-Device
the	O
key	O
labeled	O
Delete	O
(	O
sometimes	O
Delete	O
and	O
Backspace	B-Device
are	O
printed	O
on	O
the	O
same	O
key	O
)	O
serves	O
the	O
same	O
purpose	O
as	O
a	O
Backspace	B-Device
key	I-Device
.	O
</s>
<s>
The	O
Backspace	B-Device
key	I-Device
deletes	O
the	O
preceding	O
character	O
.	O
</s>
<s>
Lock	B-Device
keys	I-Device
lock	O
part	O
of	O
a	O
keyboard	B-Device
,	O
depending	O
on	O
the	O
settings	O
selected	O
.	O
</s>
<s>
The	O
lock	B-Device
keys	I-Device
are	O
scattered	O
around	O
the	O
keyboard	B-Device
.	O
</s>
<s>
Most	O
styles	O
of	O
keyboards	B-Device
have	O
three	O
LEDs	O
indicating	O
which	O
locks	O
are	O
enabled	O
,	O
in	O
the	O
upper	O
right	O
corner	O
above	O
the	O
numeric	B-Device
pad	I-Device
.	O
</s>
<s>
The	O
lock	B-Device
keys	I-Device
include	O
Scroll	B-Device
lock	I-Device
,	O
Num	B-Device
lock	I-Device
(	O
which	O
allows	O
the	O
use	O
of	O
the	O
numeric	B-Device
keypad	I-Device
)	O
,	O
and	O
Caps	B-Device
lock	I-Device
.	O
</s>
<s>
The	O
SysRq	B-Device
and	O
Print	B-Device
screen	I-Device
commands	O
often	O
share	O
the	O
same	O
key	O
.	O
</s>
<s>
SysRq	B-Device
was	O
used	O
in	O
earlier	O
computers	O
as	O
a	O
"	O
panic	O
"	O
button	O
to	O
recover	O
from	O
crashes	O
(	O
and	O
it	O
is	O
still	O
used	O
in	O
this	O
sense	O
to	O
some	O
extent	O
by	O
the	O
Linux	B-Operating_System
kernel	I-Operating_System
;	O
see	O
Magic	B-Application
SysRq	I-Application
key	I-Application
)	O
.	O
</s>
<s>
The	O
Print	B-Device
screen	I-Device
command	O
used	O
to	O
capture	O
the	O
entire	O
screen	O
and	O
send	O
it	O
to	O
the	O
printer	O
,	O
but	O
in	O
the	O
present	O
it	O
usually	O
puts	O
a	O
screenshot	O
in	O
the	O
clipboard	O
.	O
</s>
<s>
The	O
Break	B-Device
key	I-Device
can	O
be	O
used	O
by	O
software	O
in	O
several	O
different	O
ways	O
,	O
such	O
as	O
to	O
switch	O
between	O
multiple	O
login	O
sessions	O
,	O
to	O
terminate	O
a	O
program	O
,	O
or	O
to	O
interrupt	O
a	O
modem	O
connection	O
.	O
</s>
<s>
In	O
programming	O
,	O
especially	O
old	O
DOS-style	O
BASIC	O
,	O
Pascal	O
and	O
C	O
,	O
Break	O
is	O
used	O
(	O
in	O
conjunction	O
with	O
Ctrl	B-Device
)	O
to	O
stop	O
program	O
execution	O
.	O
</s>
<s>
In	O
addition	O
to	O
this	O
,	O
Linux	B-Operating_System
and	O
variants	O
,	O
as	O
well	O
as	O
many	O
DOS	O
programs	O
,	O
treat	O
this	O
combination	O
the	O
same	O
as	O
Ctrl+C	O
.	O
</s>
<s>
On	O
modern	O
keyboards	B-Device
,	O
the	O
break	B-Device
key	I-Device
is	O
usually	O
labeled	O
Pause/Break	B-Device
.	O
</s>
<s>
In	O
most	O
Windows	B-Device
environments	O
,	O
the	O
key	O
combination	O
Windows	B-Device
key+Pause	O
brings	O
up	O
the	O
system	O
properties	O
.	O
</s>
<s>
The	O
escape	B-Device
key	I-Device
(	O
)	O
has	O
a	O
variety	O
of	O
meanings	O
according	O
to	O
Operating	B-General_Concept
System	I-General_Concept
,	O
application	B-Application
or	O
both	O
.	O
</s>
<s>
It	O
triggers	O
the	O
Stop	O
function	O
in	O
many	O
web	B-Application
browsers	I-Application
.	O
</s>
<s>
The	O
escape	B-Device
key	I-Device
was	O
part	O
of	O
the	O
standard	O
keyboard	B-Device
of	O
the	O
Teletype	B-Application
Model	I-Application
33	I-Application
(	O
introduced	O
in	O
1964	O
and	O
used	O
with	O
many	O
early	O
minicomputers	O
)	O
.	O
</s>
<s>
The	O
DEC	O
VT50	B-Application
,	O
introduced	O
July	O
1974	O
,	O
also	O
had	O
an	O
Esc	B-Device
key	I-Device
.	O
</s>
<s>
The	O
TECO	B-Application
text	O
editor	O
(	O
ca	O
1963	O
)	O
and	O
its	O
descendant	O
Emacs	B-Application
(	O
ca	O
1985	O
)	O
use	O
the	O
Esc	B-Device
key	I-Device
extensively	O
.	O
</s>
<s>
Historically	O
it	O
also	O
served	O
as	O
a	O
type	O
of	O
shift	B-Device
key	I-Device
,	O
such	O
that	O
one	O
or	O
more	O
following	O
characters	O
were	O
interpreted	O
differently	O
,	O
hence	O
the	O
term	O
escape	O
sequence	O
,	O
which	O
refers	O
to	O
a	O
series	O
of	O
characters	O
,	O
usually	O
preceded	O
by	O
the	O
escape	B-Algorithm
character	I-Algorithm
.	O
</s>
<s>
On	O
machines	O
running	O
Microsoft	O
Windows	B-Device
,	O
prior	O
to	O
the	O
implementation	O
of	O
the	O
Windows	B-Device
key	I-Device
on	O
keyboards	B-Device
,	O
the	O
typical	O
practice	O
for	O
invoking	O
the	O
"	O
start	O
"	O
button	O
was	O
to	O
hold	O
down	O
the	O
control	B-Device
key	I-Device
and	O
press	O
escape	O
.	O
</s>
<s>
This	O
process	O
still	O
works	O
in	O
Windows	B-Device
95	O
,	O
98	O
,	O
Me	O
,	O
NT	O
4	O
,	O
2000	O
,	O
XP	O
,	O
Vista	O
,	O
7	O
,	O
8	O
,	O
and	O
10	O
.	O
</s>
<s>
The	O
'	O
enter	B-Device
key	I-Device
 '	O
and	O
'	O
return	B-Device
key	I-Device
 '	O
are	O
two	O
closely	O
related	O
keys	O
with	O
overlapping	O
and	O
distinct	O
functions	O
dependent	O
on	O
operating	B-General_Concept
system	I-General_Concept
and	O
application	B-Application
.	O
</s>
<s>
On	O
full-size	O
keyboards	B-Device
,	O
there	O
are	O
two	O
such	O
keys	O
,	O
one	O
in	O
the	O
alphanumeric	O
keys	O
and	O
the	O
other	O
one	O
is	O
in	O
the	O
numeric	O
keys	O
.	O
</s>
<s>
The	O
purpose	O
of	O
the	O
enter	B-Device
key	I-Device
is	O
to	O
confirm	O
what	O
has	O
been	O
typed	B-Application
.	O
</s>
<s>
The	O
return	B-Device
key	I-Device
is	O
based	O
on	O
the	O
original	O
line	O
feed/carriage	O
return	O
function	O
of	O
typewriters	O
:	O
in	O
many	O
word	B-General_Concept
processors	I-General_Concept
,	O
for	O
example	O
,	O
the	O
return	B-Device
key	I-Device
ends	O
a	O
paragraph	O
;	O
in	O
a	O
spreadsheet	O
,	O
it	O
completes	O
the	O
current	O
cell	O
and	O
move	O
to	O
the	O
next	O
cell	O
.	O
</s>
<s>
The	O
shape	O
of	O
the	O
Enter	B-Device
key	I-Device
differs	O
between	O
ISO	O
and	O
ANSI	O
keyboards	B-Device
:	O
in	O
the	O
latter	O
,	O
the	O
Enter	B-Device
key	I-Device
is	O
in	O
a	O
single	O
row	O
(	O
usually	O
the	O
third	O
from	O
the	O
bottom	O
)	O
while	O
in	O
the	O
former	O
it	O
spans	O
over	O
two	O
rows	O
and	O
has	O
an	O
inverse	O
L	O
shape	O
.	O
</s>
<s>
For	O
other	O
keys	O
,	O
the	O
key	O
is	O
engraved	B-Application
with	O
symbols	O
for	O
both	O
the	O
unshifted	O
and	O
shifted	O
result	O
.	O
</s>
<s>
When	O
used	O
in	O
combination	O
with	O
other	O
control	B-Device
keys	I-Device
(	O
such	O
as	O
,	O
or	O
)	O
,	O
the	O
effect	O
is	O
system	O
and	O
application	B-Application
dependent	O
.	O
</s>
<s>
The	O
Menu	O
key	O
or	O
Application	B-Application
key	O
is	O
a	O
key	O
found	O
on	O
Windows-oriented	O
computer	B-Device
keyboards	I-Device
.	O
</s>
<s>
It	O
is	O
used	O
to	O
launch	O
a	O
context	O
menu	O
with	O
the	O
keyboard	B-Device
rather	O
than	O
with	O
the	O
usual	O
right	O
mouse	O
button	O
.	O
</s>
<s>
On	O
some	O
Samsung	O
keyboards	B-Device
the	O
cursor	O
in	O
the	O
icon	O
is	O
not	O
present	O
,	O
showing	O
the	O
menu	O
only	O
.	O
</s>
<s>
This	O
key	O
was	O
created	O
at	O
the	O
same	O
time	O
as	O
the	O
Windows	B-Device
key	I-Device
.	O
</s>
<s>
Some	O
Windows	B-Device
public	O
terminals	O
do	O
not	O
have	O
a	O
Menu	O
key	O
on	O
their	O
keyboard	B-Device
to	O
prevent	O
users	O
from	O
right-clicking	O
(	O
however	O
,	O
in	O
many	O
Windows	B-Device
applications	O
,	O
a	O
similar	O
functionality	O
can	O
be	O
invoked	O
with	O
the	O
Shift+F10	O
keyboard	B-Device
shortcut	O
)	O
.	O
</s>
<s>
Many	O
,	O
but	O
not	O
all	O
,	O
computer	B-Device
keyboards	I-Device
have	O
a	O
numeric	B-Device
keypad	I-Device
to	O
the	O
right	O
of	O
the	O
alphabetic	O
keyboard	B-Device
,	O
often	O
separated	O
from	O
the	O
other	O
groups	O
of	O
keys	O
such	O
as	O
the	O
function	B-Application
keys	I-Application
and	O
system	O
command	B-Device
keys	I-Device
,	O
which	O
contains	O
numbers	O
,	O
basic	O
mathematical	O
symbols	O
(	O
e.g.	O
,	O
addition	O
,	O
subtraction	O
,	O
etc	O
.	O
</s>
<s>
)	O
,	O
and	O
a	O
few	O
function	B-Application
keys	I-Application
.	O
</s>
<s>
In	O
addition	O
to	O
the	O
row	O
of	O
number	O
keys	O
above	O
the	O
top	O
alphabetic	O
row	O
,	O
most	O
desktop	O
keyboards	B-Device
have	O
a	O
number	B-Device
pad	I-Device
or	O
accounting	O
pad	O
,	O
on	O
the	O
right	O
hand	O
side	O
of	O
the	O
keyboard	B-Device
.	O
</s>
<s>
While	O
num	B-Device
lock	I-Device
is	O
set	O
,	O
the	O
numbers	O
on	O
these	O
keys	O
duplicate	O
the	O
number	O
row	O
;	O
if	O
not	O
,	O
they	O
have	O
alternative	O
functions	O
as	O
engraved	B-Application
.	O
</s>
<s>
The	O
enter	B-Device
key	I-Device
in	O
this	O
keys	O
indicate	O
the	O
equal	O
sign	O
.	O
</s>
<s>
On	O
Japanese/Korean	O
keyboards	B-Device
,	O
there	O
may	O
be	O
Language	B-Device
input	I-Device
keys	I-Device
for	O
changing	O
the	O
language	O
to	O
use	O
.	O
</s>
<s>
Some	O
keyboards	B-Device
have	O
power	O
management	O
keys	O
(	O
e.g.	O
,	O
power	O
key	O
,	O
sleep	O
key	O
and	O
wake	O
key	O
)	O
;	O
Internet	O
keys	O
to	O
access	O
a	O
web	B-Application
browser	I-Application
or	O
E-mail	O
;	O
and/or	O
multimedia	O
keys	O
,	O
such	O
as	O
volume	O
controls	O
;	O
or	O
keys	O
that	O
can	O
be	O
programmed	O
by	O
the	O
user	O
to	O
launch	O
a	O
specified	O
application	B-Application
or	O
a	O
command	O
like	O
minimizing	O
all	O
windows	B-Device
.	O
</s>
<s>
It	O
is	O
possible	O
to	O
install	O
multiple	O
keyboard	B-Device
layouts	O
within	O
an	O
operating	B-General_Concept
system	I-General_Concept
and	O
switch	O
between	O
them	O
,	O
either	O
through	O
features	O
implemented	O
within	O
the	O
OS	O
,	O
or	O
through	O
an	O
external	O
application	B-Application
.	O
</s>
<s>
Microsoft	O
Windows	B-Device
,	O
Linux	B-Operating_System
,	O
and	O
Mac	O
provide	O
support	O
to	O
add	O
keyboard	B-Device
layouts	O
and	O
choose	O
from	O
them	O
.	O
</s>
<s>
Keyboards	B-Device
and	O
keypads	B-Device
may	O
be	O
illuminated	O
from	O
inside	O
,	O
especially	O
on	O
equipment	O
for	O
mobile	O
use	O
.	O
</s>
<s>
Both	O
keyboards	B-Device
built	O
into	O
computers	O
and	O
external	O
ones	O
may	O
support	O
backlighting	O
;	O
external	O
backlit	O
keyboards	B-Device
may	O
have	O
a	O
wired	O
USB	B-Protocol
connection	O
,	O
or	O
be	O
connected	O
wirelessly	O
and	O
powered	O
by	O
batteries	O
.	O
</s>
<s>
Illumination	O
facilitates	O
the	O
use	O
of	O
the	O
keyboard	B-Device
or	O
keypad	B-Device
in	O
dark	O
environments	O
.	O
</s>
<s>
Many	O
gaming	O
keyboards	B-Device
are	O
designed	O
to	O
have	O
an	O
aesthetic	O
as	O
well	O
as	O
functional	O
appeal	O
,	O
with	O
multiple	O
colours	O
,	O
and	O
colour-coded	O
keys	O
to	O
make	O
it	O
easier	O
for	O
gamers	O
to	O
find	O
command	B-Device
keys	I-Device
while	O
playing	O
in	O
a	O
dark	O
room	O
.	O
</s>
<s>
Many	O
keyboards	B-Device
not	O
otherwise	O
illuminated	O
may	O
have	O
small	O
LED	O
indicator	O
lights	O
in	O
a	O
few	O
important	O
function	B-Application
keys	I-Application
,	O
or	O
elsewhere	O
on	O
the	O
housing	O
,	O
if	O
their	O
function	O
is	O
activated	O
(	O
see	O
photo	O
)	O
.	O
</s>
<s>
In	O
the	O
first	O
electronic	O
keyboards	B-Device
in	O
the	O
early	O
1970s	O
,	O
the	O
key	O
switches	O
were	O
individual	O
switches	O
inserted	O
into	O
holes	O
in	O
metal	O
frames	O
.	O
</s>
<s>
These	O
keyboards	B-Device
cost	O
from	O
80	O
to	O
120USD	O
and	O
were	O
used	O
in	O
mainframe	O
data	O
terminals	O
.	O
</s>
<s>
In	O
1978	O
,	O
Key	O
Tronic	O
Corporation	O
introduced	O
keyboards	B-Device
with	O
capacitive-based	O
switches	O
,	O
one	O
of	O
the	O
first	O
keyboard	B-Device
technologies	O
not	O
to	O
use	O
self-contained	O
switches	O
.	O
</s>
<s>
These	O
keyboards	B-Device
were	O
claimed	O
to	O
have	O
the	O
same	O
reliability	O
as	O
the	O
other	O
"	O
solid-state	O
switch	O
"	O
keyboards	B-Device
such	O
as	O
inductive	O
and	O
Hall-effect	O
,	O
but	O
competitive	O
with	O
direct-contact	O
keyboards	B-Device
.	O
</s>
<s>
Prices	O
of	O
$60	O
for	O
keyboards	B-Device
were	O
achieved	O
,	O
and	O
Key	O
Tronic	O
rapidly	O
became	O
the	O
largest	O
independent	O
keyboard	B-Device
manufacturer	O
.	O
</s>
<s>
Meanwhile	O
,	O
IBM	O
made	O
their	O
own	O
keyboards	B-Device
,	O
using	O
their	O
own	O
patented	O
technology	O
:	O
Keys	O
on	O
older	O
IBM	O
keyboards	B-Device
were	O
made	O
with	O
a	O
"	O
buckling	O
spring	O
"	O
mechanism	O
,	O
in	O
which	O
a	O
coil	O
spring	O
under	O
the	O
key	O
buckles	O
under	O
pressure	O
from	O
the	O
user	O
's	O
finger	O
,	O
triggering	O
a	O
hammer	O
that	O
presses	O
two	O
plastic	O
sheets	O
(	O
membranes	O
)	O
with	O
conductive	O
traces	O
together	O
,	O
completing	O
a	O
circuit	O
.	O
</s>
<s>
The	O
first	O
electronic	O
keyboards	B-Device
had	O
a	O
typewriter	O
key	O
travel	O
distance	O
of	O
0.187inches	O
(	O
4.75mm	O
)	O
,	O
keytops	O
were	O
a	O
half-inch	O
(	O
12.7mm	O
)	O
high	O
,	O
and	O
keyboards	B-Device
were	O
about	O
two	O
inches	O
(	O
5cm	O
)	O
thick	O
.	O
</s>
<s>
Coincident	O
with	O
this	O
,	O
Key	O
Tronic	O
was	O
the	O
first	O
company	O
to	O
introduce	O
a	O
keyboard	B-Device
that	O
was	O
only	O
about	O
one	O
inch	O
thick	O
.	O
</s>
<s>
And	O
now	O
keyboards	B-Device
measure	O
only	O
about	O
a	O
half-inch	O
thick	O
.	O
</s>
<s>
Keytops	O
are	O
an	O
important	O
element	O
of	O
keyboards	B-Device
.	O
</s>
<s>
In	O
the	O
beginning	O
,	O
keyboard	B-Device
keytops	O
had	O
a	O
"	O
dish	O
shape	O
"	O
on	O
top	O
,	O
like	O
typewriters	O
before	O
them	O
.	O
</s>
<s>
Keyboard	B-Device
key	O
legends	O
must	O
be	O
extremely	O
durable	O
over	O
tens	O
of	O
millions	O
of	O
depressions	O
,	O
since	O
they	O
are	O
subjected	O
to	O
extreme	O
mechanical	O
wear	O
from	O
fingers	O
and	O
fingernails	O
,	O
and	O
subject	O
to	O
hand	O
oils	O
and	O
creams	O
,	O
so	O
engraving	B-Application
and	O
filling	O
key	O
legends	O
with	O
paint	O
,	O
as	O
was	O
done	O
previously	O
for	O
individual	O
switches	O
,	O
was	O
never	O
acceptable	O
.	O
</s>
<s>
So	O
,	O
for	O
the	O
first	O
electronic	O
keyboards	B-Device
,	O
the	O
key	O
legends	O
were	O
produced	O
by	O
two-shot	O
(	O
or	O
double-shot	O
,	O
or	O
two-color	O
)	O
molding	O
,	O
where	O
either	O
the	O
key	O
shell	O
or	O
the	O
inside	O
of	O
the	O
key	O
with	O
the	O
key	O
legend	O
was	O
molded	O
first	O
,	O
and	O
then	O
the	O
other	O
color	O
molded	O
second	O
.	O
</s>
<s>
But	O
,	O
to	O
save	O
cost	O
,	O
other	O
methods	O
were	O
explored	O
,	O
such	O
as	O
sublimation	O
printing	O
and	O
laser	O
engraving	B-Application
,	O
both	O
methods	O
which	O
could	O
be	O
used	O
to	O
print	O
a	O
whole	O
keyboard	B-Device
at	O
the	O
same	O
time	O
.	O
</s>
<s>
Initially	O
,	O
sublimation	O
printing	O
,	O
where	O
a	O
special	O
ink	O
is	O
printed	O
onto	O
the	O
keycap	B-Device
surface	O
and	O
the	O
application	B-Application
of	O
heat	O
causes	O
the	O
ink	O
molecules	O
to	O
penetrate	O
and	O
commingle	O
with	O
the	O
plastic	O
modules	O
,	O
had	O
a	O
problem	O
because	O
finger	O
oils	O
caused	O
the	O
molecules	O
to	O
disperse	O
,	O
but	O
then	O
a	O
necessarily	O
very	O
hard	O
clear	O
coating	O
was	O
applied	O
to	O
prevent	O
this	O
.	O
</s>
<s>
Coincident	O
with	O
sublimation	O
printing	O
,	O
which	O
was	O
first	O
used	O
in	O
high	O
volume	O
by	O
IBM	O
on	O
their	O
keyboards	B-Device
,	O
was	O
the	O
introduction	O
by	O
IBM	O
of	O
single-curved-dish	O
keycaps	B-Device
to	O
facilitate	O
quality	O
printing	O
of	O
key	O
legends	O
by	O
having	O
a	O
consistently	O
curved	O
surface	O
instead	O
of	O
a	O
dish	O
.	O
</s>
<s>
On	O
another	O
note	O
,	O
IBM	O
was	O
unique	O
in	O
using	O
separate	O
shells	O
,	O
or	O
"	O
keycaps	B-Device
"	O
,	O
on	O
keytop	O
bases	O
.	O
</s>
<s>
This	O
might	O
have	O
made	O
their	O
manufacturing	O
of	O
different	O
keyboard	B-Device
layouts	O
more	O
flexible	O
,	O
but	O
the	O
reason	O
for	O
doing	O
this	O
was	O
that	O
the	O
plastic	O
material	O
that	O
needed	O
to	O
be	O
used	O
for	O
sublimation	O
printing	O
was	O
different	O
from	O
standard	O
ABS	O
keytop	O
plastic	O
material	O
.	O
</s>
<s>
Three	O
final	O
mechanical	O
technologies	O
brought	O
keyboards	B-Device
to	O
where	O
they	O
are	O
today	O
,	O
driving	O
the	O
cost	O
well	O
under	O
$10	O
:	O
</s>
<s>
"	O
Monoblock	O
"	O
keyboard	B-Device
designs	O
were	O
developed	O
where	O
individual	O
switch	O
housings	O
were	O
eliminated	O
and	O
a	O
one-piece	O
"	O
monoblock	O
"	O
housing	O
used	O
instead	O
.	O
</s>
<s>
This	O
was	O
possible	O
because	O
of	O
molding	O
techniques	O
that	O
could	O
provide	O
very	O
tight	O
tolerances	O
for	O
the	O
switch-plunger	O
holes	O
and	O
guides	O
across	O
the	O
width	O
of	O
the	O
keyboard	B-Device
so	O
that	O
the	O
key	O
plunger-to-housing	O
clearances	O
were	O
not	O
too	O
tight	O
or	O
too	O
loose	O
,	O
either	O
of	O
which	O
could	O
cause	O
the	O
keys	O
to	O
bind	O
.	O
</s>
<s>
The	O
membrane	O
layers	O
can	O
be	O
printed	O
by	O
very-high	O
volume	O
,	O
low-cost	O
"	O
reel-to-reel	O
"	O
printing	O
machines	O
,	O
with	O
each	O
keyboard	B-Device
membrane	O
cut	O
and	O
punched	O
out	O
afterwards	O
.	O
</s>
<s>
Plastic	O
materials	O
played	O
a	O
very	O
important	O
part	O
in	O
the	O
development	O
and	O
progress	O
of	O
electronic	O
keyboards	B-Device
.	O
</s>
<s>
Until	O
"	O
monoblocks	O
"	O
came	O
along	O
,	O
GE	O
's	O
"	O
self-lubricating	O
"	O
Delrin	O
was	O
the	O
only	O
plastic	O
material	O
for	O
keyboard	B-Device
switch	O
plungers	O
that	O
could	O
withstand	O
the	O
beating	O
over	O
tens	O
of	O
millions	O
of	O
cycles	O
of	O
lifetime	O
use	O
.	O
</s>
<s>
Greasing	O
or	O
oiling	O
switch	O
plungers	O
was	O
undesirable	O
because	O
it	O
would	O
attract	O
dirt	O
over	O
time	O
which	O
would	O
eventually	O
affect	O
the	O
feel	O
and	O
even	O
bind	O
the	O
key	O
switches	O
(	O
although	O
keyboard	B-Device
manufacturers	O
would	O
sometimes	O
sneak	O
this	O
into	O
their	O
keyboards	B-Device
,	O
especially	O
if	O
they	O
could	O
not	O
control	B-Device
the	O
tolerances	O
of	O
the	O
key	O
plungers	O
and	O
housings	O
well	O
enough	O
to	O
have	O
a	O
smooth	O
key	O
depression	O
feel	O
or	O
prevent	O
binding	O
)	O
.	O
</s>
<s>
However	O
,	O
as	O
plastic	O
molding	O
advanced	O
in	O
maintaining	O
tight	O
tolerances	O
,	O
and	O
as	O
key	O
travel	O
length	O
reduced	O
from	O
0.187-inch	O
to	O
0.110-inch	O
(	O
4.75mm	O
to	O
2.79mm	O
)	O
,	O
single-part	O
keytop/plungers	O
could	O
be	O
made	O
of	O
ABS	O
,	O
with	O
the	O
keyboard	B-Device
monoblocks	O
also	O
made	O
of	O
ABS	O
.	O
</s>
<s>
In	O
common	O
use	O
,	O
the	O
term	O
"	O
mechanical	O
keyboard	B-Device
"	O
refers	O
to	O
a	O
keyboard	B-Device
with	O
individual	O
mechanical	O
key	O
switches	O
,	O
each	O
of	O
which	O
contains	O
a	O
fully	O
encased	O
plunger	O
with	O
a	O
spring	O
below	O
it	O
and	O
metallic	O
electrical	O
contacts	O
on	O
a	O
side	O
.	O
</s>
<s>
Analog	O
keyboards	B-Device
with	O
key	O
switches	O
whose	O
activation	O
distance	O
can	O
be	O
reconfigured	O
through	O
software	O
,	O
optical	O
switches	O
that	O
work	O
by	O
blocking	O
laser	O
beams	O
,	O
and	O
Hall	O
Effect	O
keyboards	B-Device
that	O
use	O
key	O
switches	O
that	O
use	O
a	O
magnet	O
to	O
activate	O
a	O
hall	O
sensor	O
,	O
are	O
also	O
available	O
.	O
</s>
<s>
Computer	B-Device
keyboards	I-Device
include	O
control	B-Device
circuitry	I-Device
to	O
convert	O
key	O
presses	O
into	O
key	O
codes	O
(	O
usually	O
scancodes	O
)	O
that	O
the	O
computer	O
's	O
electronics	O
can	O
understand	O
.	O
</s>
<s>
The	O
first	O
computer	B-Device
keyboards	I-Device
were	O
for	O
mainframe	O
computer	O
data	O
terminals	O
and	O
used	O
discrete	O
electronic	O
parts	O
.	O
</s>
<s>
The	O
first	O
keyboard	B-Device
microprocessor	O
was	O
introduced	O
in	O
1972	O
by	O
General	O
Instruments	O
,	O
but	O
keyboards	B-Device
have	O
been	O
using	O
the	O
single-chip	O
8048	B-Device
microcontroller	B-Architecture
variant	O
since	O
it	O
became	O
available	O
in	O
1978	O
.	O
</s>
<s>
The	O
keyboard	B-Device
switch	O
matrix	O
is	O
wired	O
to	O
its	O
inputs	O
,	O
it	O
converts	O
the	O
keystrokes	O
to	O
key	O
codes	O
,	O
and	O
,	O
for	O
a	O
detached	O
keyboard	B-Device
,	O
sends	O
the	O
codes	O
down	O
a	O
serial	O
cable	O
(	O
the	O
keyboard	B-Device
cord	O
)	O
to	O
the	O
main	O
processor	O
on	O
the	O
computer	O
motherboard	O
.	O
</s>
<s>
This	O
serial	O
keyboard	B-Device
cable	O
communication	O
is	O
only	O
bi-directional	O
to	O
the	O
extent	O
that	O
the	O
computer	O
's	O
electronics	O
controls	O
the	O
illumination	O
of	O
the	O
caps	B-Device
lock	I-Device
,	O
num	B-Device
lock	I-Device
and	O
scroll	B-Device
lock	I-Device
lights	I-Device
.	O
</s>
<s>
One	O
test	O
for	O
whether	O
the	O
computer	O
has	O
crashed	O
is	O
pressing	O
the	O
caps	B-Device
lock	I-Device
key	I-Device
.	O
</s>
<s>
The	O
keyboard	B-Device
sends	O
the	O
key	O
code	O
to	O
the	O
keyboard	B-Application
driver	I-Application
running	O
in	O
the	O
main	O
computer	O
;	O
if	O
the	O
main	O
computer	O
is	O
operating	O
,	O
it	O
commands	O
the	O
light	O
to	O
turn	O
on	O
.	O
</s>
<s>
The	O
keyboard	B-Application
driver	I-Application
also	O
tracks	O
the	O
Shift	O
,	O
alt	B-Device
and	O
control	B-Device
state	O
of	O
the	O
keyboard	B-Device
.	O
</s>
<s>
Some	O
lower-quality	O
keyboards	B-Device
have	O
multiple	O
or	O
false	O
key	O
entries	O
due	O
to	O
inadequate	O
electrical	O
designs	O
.	O
</s>
<s>
When	O
pressing	O
a	O
keyboard	B-Device
key	O
,	O
the	O
key	O
contacts	O
may	O
"	O
bounce	O
"	O
against	O
each	O
other	O
for	O
several	O
milliseconds	O
before	O
they	O
settle	O
into	O
firm	O
contact	O
.	O
</s>
<s>
To	O
resolve	O
this	O
problem	O
,	O
the	O
processor	O
in	O
a	O
keyboard	B-Device
(	O
or	O
computer	O
)	O
"	O
debounces	O
"	O
the	O
keystrokes	O
,	O
by	O
aggregating	O
them	O
across	O
time	O
to	O
produce	O
one	O
"	O
confirmed	O
"	O
keystroke	O
.	O
</s>
<s>
Some	O
low-quality	O
keyboards	B-Device
also	O
suffer	O
problems	O
with	O
rollover	B-Device
(	O
that	O
is	O
,	O
when	O
multiple	O
keys	O
pressed	O
at	O
the	O
same	O
time	O
,	O
or	O
when	O
keys	O
are	O
pressed	O
so	O
fast	O
that	O
multiple	O
keys	O
are	O
down	O
within	O
the	O
same	O
milliseconds	O
)	O
.	O
</s>
<s>
Early	O
"	O
solid-state	O
"	O
keyswitch	O
keyboards	B-Device
did	O
not	O
have	O
this	O
problem	O
because	O
the	O
keyswitches	O
are	O
electrically	O
isolated	O
from	O
each	O
other	O
,	O
and	O
early	O
"	O
direct-contact	O
"	O
keyswitch	O
keyboards	B-Device
avoided	O
this	O
problem	O
by	O
having	O
isolation	O
diodes	O
for	O
every	O
keyswitch	O
.	O
</s>
<s>
These	O
early	O
keyboards	B-Device
had	O
"	O
n-key	O
"	O
rollover	B-Device
,	O
which	O
means	O
any	O
number	O
of	O
keys	O
can	O
be	O
depressed	O
and	O
the	O
keyboard	B-Device
will	O
still	O
recognize	O
the	O
next	O
key	O
depressed	O
.	O
</s>
<s>
But	O
when	O
three	O
keys	O
are	O
pressed	O
(	O
electrically	O
closed	O
)	O
at	O
the	O
same	O
time	O
in	O
a	O
"	O
direct	O
contact	O
"	O
keyswitch	O
matrix	O
that	O
does	O
n't	O
have	O
isolation	O
diodes	O
,	O
the	O
keyboard	B-Device
electronics	O
can	O
see	O
a	O
fourth	O
"	O
phantom	O
"	O
key	O
which	O
is	O
the	O
intersection	O
of	O
the	O
X	O
and	O
Y	O
lines	O
of	O
the	O
three	O
keys	O
.	O
</s>
<s>
Some	O
types	O
of	O
keyboard	B-Device
circuitry	O
will	O
register	O
a	O
maximum	O
number	O
of	O
keys	O
at	O
one	O
time	O
.	O
</s>
<s>
"	O
Three-key	O
"	O
rollover	B-Device
,	O
also	O
called	O
"	O
phantom	O
key	O
blocking	O
"	O
or	O
"	O
phantom	O
key	O
lockout	O
"	O
,	O
will	O
only	O
register	O
three	O
keys	O
and	O
ignore	O
all	O
others	O
until	O
one	O
of	O
the	O
three	O
keys	O
is	O
lifted	O
.	O
</s>
<s>
This	O
is	O
undesirable	O
,	O
especially	O
for	O
fast	O
typing	B-Application
(	O
hitting	O
new	O
keys	O
before	O
the	O
fingers	O
can	O
release	O
previous	O
keys	O
)	O
,	O
and	O
games	O
(	O
designed	O
for	O
multiple	O
key	O
presses	O
)	O
.	O
</s>
<s>
As	O
direct-contact	O
membrane	O
keyboards	B-Device
became	O
popular	O
,	O
the	O
available	O
rollover	B-Device
of	O
keys	O
was	O
optimized	O
by	O
analyzing	O
the	O
most	O
common	O
key	O
sequences	O
and	O
placing	O
these	O
keys	O
so	O
that	O
they	O
do	O
not	O
potentially	O
produce	O
phantom	O
keys	O
in	O
the	O
electrical	O
key	O
matrix	O
(	O
for	O
example	O
,	O
simply	O
placing	O
three	O
or	O
four	O
keys	O
that	O
might	O
be	O
depressed	O
simultaneously	O
on	O
the	O
same	O
X	O
or	O
same	O
Y	O
line	O
,	O
so	O
that	O
a	O
phantom	O
key	O
intersection/short	O
cannot	O
happen	O
)	O
,	O
so	O
that	O
blocking	O
a	O
third	O
key	O
usually	O
is	O
n't	O
a	O
problem	O
.	O
</s>
<s>
But	O
lower-quality	O
keyboard	B-Device
designs	O
and	O
unknowledgeable	O
engineers	O
may	O
not	O
know	O
these	O
tricks	O
,	O
and	O
it	O
can	O
still	O
be	O
a	O
problem	O
in	O
games	O
due	O
to	O
wildly	O
different	O
or	O
configurable	O
layouts	O
in	O
different	O
games	O
.	O
</s>
<s>
There	O
are	O
several	O
ways	O
of	O
connecting	O
a	O
keyboard	B-Device
to	O
a	O
system	B-General_Concept
unit	I-General_Concept
(	O
more	O
precisely	O
,	O
to	O
its	O
keyboard	B-Device
controller	I-Device
)	O
using	O
cables	O
,	O
including	O
the	O
standard	O
AT	B-Device
connector	I-Device
commonly	O
found	O
on	O
motherboards	O
,	O
which	O
was	O
eventually	O
replaced	O
by	O
the	O
PS/2	B-Protocol
and	O
the	O
USB	B-Protocol
connection	O
.	O
</s>
<s>
Prior	O
to	O
the	O
iMac	O
line	O
of	O
systems	O
,	O
Apple	O
used	O
the	O
proprietary	O
Apple	B-Device
Desktop	I-Device
Bus	I-Device
for	O
its	O
keyboard	B-Device
connector	O
.	O
</s>
<s>
Wireless	O
keyboards	B-Device
have	O
become	O
popular	O
.	O
</s>
<s>
A	O
wireless	O
keyboard	B-Device
must	O
have	O
a	O
transmitter	O
built	O
in	O
,	O
and	O
a	O
receiver	O
connected	O
to	O
the	O
computer	O
's	O
keyboard	B-Device
port	O
;	O
it	O
communicates	O
either	O
by	O
radio	O
frequency	O
(	O
RF	O
)	O
or	O
infrared	O
(	O
IR	O
)	O
signals	O
.	O
</s>
<s>
A	O
wireless	O
keyboard	B-Device
may	O
use	O
industry	O
standard	O
Bluetooth	B-Protocol
radio	O
communication	O
,	O
in	O
which	O
case	O
the	O
receiver	O
may	O
be	O
built	O
into	O
the	O
computer	O
.	O
</s>
<s>
Wireless	O
keyboards	B-Device
need	O
batteries	O
for	O
power	O
,	O
and	O
may	O
be	O
at	O
risk	O
of	O
data	O
eavesdropping	O
.	O
</s>
<s>
Wireless	O
solar	O
keyboards	B-Device
charge	O
their	O
batteries	O
from	O
small	O
solar	O
panels	O
using	O
natural	O
or	O
artificial	O
light	O
.	O
</s>
<s>
The	O
1984	O
Apricot	B-Device
Portable	I-Device
is	O
an	O
early	O
example	O
of	O
an	O
IR	O
keyboard	B-Device
.	O
</s>
<s>
Optical	B-Application
character	I-Application
recognition	I-Application
(	O
OCR	O
)	O
is	O
preferable	O
to	O
rekeying	O
for	O
converting	O
existing	O
text	O
that	O
is	O
already	O
written	O
down	O
but	O
not	O
in	O
machine-readable	O
format	O
(	O
for	O
example	O
,	O
a	O
Linotype-composed	O
book	O
from	O
the	O
1940s	O
)	O
.	O
</s>
<s>
OCR	O
technology	O
has	O
already	O
reached	O
an	O
impressive	O
state	O
(	O
for	O
example	O
,	O
Google	B-Application
Book	I-Application
Search	I-Application
)	O
and	O
promises	O
more	O
for	O
the	O
future	O
.	O
</s>
<s>
Speech	B-Application
recognition	I-Application
converts	O
speech	O
into	O
machine-readable	O
text	O
(	O
that	O
is	O
,	O
a	O
string	O
of	O
character	O
codes	O
)	O
.	O
</s>
<s>
This	O
technology	O
has	O
also	O
reached	O
an	O
advanced	O
state	O
and	O
is	O
implemented	O
in	O
various	B-General_Concept
software	I-General_Concept
products	I-General_Concept
.	O
</s>
<s>
For	O
certain	O
uses	O
(	O
e.g.	O
,	O
transcription	O
of	O
medical	O
or	O
legal	O
dictation	O
;	O
journalism	O
;	O
writing	O
essays	O
or	O
novels	O
)	O
speech	B-Application
recognition	I-Application
is	O
starting	O
to	O
replace	O
the	O
keyboard	B-Device
.	O
</s>
<s>
However	O
,	O
the	O
lack	O
of	O
privacy	O
when	O
issuing	O
voice	B-Application
commands	I-Application
and	O
dictation	O
makes	O
this	O
kind	O
of	O
input	O
unsuitable	O
for	O
many	O
environments	O
.	O
</s>
<s>
Pointing	B-Device
devices	I-Device
can	O
be	O
used	O
to	O
enter	O
text	O
or	O
characters	O
in	O
contexts	O
where	O
using	O
a	O
physical	O
keyboard	B-Device
would	O
be	O
inappropriate	O
or	O
impossible	O
.	O
</s>
<s>
Popular	O
examples	O
of	O
this	O
kind	O
of	O
input	O
are	O
Graffiti	B-Application
,	O
Dasher	B-Language
and	O
on-screen	O
virtual	B-Device
keyboards	I-Device
.	O
</s>
<s>
Unencrypted	O
wireless	O
Bluetooth	B-Protocol
keyboards	B-Device
are	O
known	O
to	O
be	O
vulnerable	O
to	O
signal	O
theft	O
by	O
placing	O
a	O
covert	O
listening	O
device	O
in	O
the	O
same	O
room	O
as	O
the	O
keyboard	B-Device
to	O
sniff	O
and	O
record	O
Bluetooth	B-Protocol
packets	O
for	O
the	O
purpose	O
of	O
logging	O
keys	O
typed	B-Application
by	O
the	O
user	O
.	O
</s>
<s>
Microsoft	O
wireless	O
keyboards	B-Device
2011	O
and	O
earlier	O
are	O
documented	O
to	O
have	O
this	O
vulnerability	O
.	O
</s>
<s>
Hardware	O
key	O
loggers	O
are	O
attached	O
to	O
the	O
keyboard	B-Device
cable	O
or	O
installed	O
inside	O
standard	O
keyboards	B-Device
.	O
</s>
<s>
Software	O
keyloggers	O
work	O
on	O
the	O
target	O
computer	O
's	O
operating	B-General_Concept
system	I-General_Concept
and	O
gain	O
unauthorized	O
access	O
to	O
the	O
hardware	O
,	O
hook	O
into	O
the	O
keyboard	B-Device
with	O
functions	O
provided	O
by	O
the	O
OS	O
,	O
or	O
use	O
remote	O
access	O
software	O
to	O
transmit	O
recorded	O
data	O
out	O
of	O
the	O
target	O
computer	O
to	O
a	O
remote	O
location	O
.	O
</s>
<s>
Some	O
hackers	O
also	O
use	O
wireless	O
keylogger	O
sniffers	O
to	O
collect	O
packets	O
of	O
data	O
being	O
transferred	O
from	O
a	O
wireless	O
keyboard	B-Device
and	O
its	O
receiver	O
,	O
and	O
then	O
they	O
crack	O
the	O
encryption	O
key	O
being	O
used	O
to	O
secure	O
wireless	O
communications	O
between	O
the	O
two	O
devices	O
.	O
</s>
<s>
Enabling	O
a	O
firewall	B-Application
does	O
not	O
stop	O
keyloggers	O
per	O
se	O
,	O
but	O
can	O
possibly	O
prevent	O
transmission	O
of	O
the	O
logged	O
material	O
over	O
the	O
net	O
if	O
properly	O
configured	O
.	O
</s>
<s>
Network	O
monitors	O
(	O
also	O
known	O
as	O
reverse-firewalls	O
)	O
can	O
be	O
used	O
to	O
alert	O
the	O
user	O
whenever	O
an	O
application	B-Application
attempts	O
to	O
make	O
a	O
network	O
connection	O
.	O
</s>
<s>
This	O
gives	O
the	O
user	O
the	O
chance	O
to	O
prevent	O
the	O
keylogger	O
from	O
"	O
phoning	O
home	O
"	O
with	O
his	O
or	O
her	O
typed	B-Application
information	O
.	O
</s>
<s>
Automatic	O
form-filling	O
programs	O
can	O
prevent	O
keylogging	O
entirely	O
by	O
not	O
using	O
the	O
keyboard	B-Device
at	O
all	O
.	O
</s>
<s>
Historically	O
,	O
most	O
keyloggers	O
could	O
be	O
fooled	O
by	O
alternating	O
between	O
typing	B-Application
the	O
login	O
credentials	O
and	O
typing	B-Application
characters	O
somewhere	O
else	O
in	O
the	O
focus	O
window	O
.	O
</s>
<s>
Keyboards	B-Device
are	O
also	O
known	O
to	O
emit	O
electromagnetic	O
signatures	O
that	O
can	O
be	O
detected	O
using	O
special	O
spying	O
equipment	O
to	O
reconstruct	O
the	O
keys	O
pressed	O
on	O
the	O
keyboard	B-Device
.	O
</s>
<s>
The	O
use	O
of	O
any	O
keyboard	B-Device
may	O
cause	O
serious	O
injury	O
(	O
that	O
is	O
,	O
carpal	O
tunnel	O
syndrome	O
or	O
other	O
repetitive	O
strain	O
injury	O
)	O
to	O
hands	O
,	O
wrists	O
,	O
arms	O
,	O
neck	O
or	O
back	O
.	O
</s>
<s>
When	O
inputting	O
at	O
the	O
keyboard	B-Device
,	O
a	O
person	O
should	O
keep	O
the	O
shoulders	O
relaxed	O
with	O
the	O
elbows	O
at	O
the	O
side	O
,	O
with	O
the	O
keyboard	B-Device
and	O
mouse	O
positioned	O
so	O
that	O
reaching	O
is	O
not	O
necessary	O
.	O
</s>
<s>
The	O
chair	O
height	O
and	O
keyboard	B-Device
tray	O
should	O
be	O
adjusted	O
so	O
that	O
the	O
wrists	O
are	O
straight	O
,	O
and	O
the	O
wrists	O
should	O
not	O
be	O
rested	O
on	O
sharp	O
table	O
edges	O
.	O
</s>
<s>
Wrist	O
or	O
palm	O
rests	O
should	O
not	O
be	O
used	O
while	O
typing	B-Application
.	O
</s>
<s>
Some	O
adaptive	O
technology	O
ranging	O
from	O
special	O
keyboards	B-Device
,	O
mouse	O
replacements	O
and	O
pen	O
tablet	B-Device
interfaces	O
to	O
speech	B-Application
recognition	I-Application
software	I-Application
can	O
reduce	O
the	O
risk	O
of	O
injury	O
.	O
</s>
<s>
By	O
using	O
a	O
touchpad	B-Application
or	O
a	O
stylus	O
pen	O
with	O
a	O
graphic	O
tablet	B-Device
,	O
in	O
place	O
of	O
a	O
mouse	O
,	O
one	O
can	O
lessen	O
the	O
repetitive	O
strain	O
on	O
the	O
arms	O
and	O
hands	O
.	O
</s>
