<s>
The	O
keyboard	B-Device
for	O
IBM	O
PC-compatible	O
computers	O
is	O
standardized	O
.	O
</s>
<s>
However	O
,	O
during	O
the	O
more	O
than	O
30	O
years	O
of	O
PC	O
architecture	O
being	O
frequently	O
updated	O
,	O
many	O
keyboard	B-Device
layout	O
variations	O
have	O
been	O
developed	O
.	O
</s>
<s>
A	O
well-known	O
class	O
of	O
IBM	B-Device
PC	I-Device
keyboards	I-Device
is	O
the	O
Model	B-Device
M	I-Device
.	O
Introduced	O
in	O
1984	O
and	O
manufactured	O
by	O
IBM	O
,	O
Lexmark	O
,	O
Maxi-Switch	O
and	O
Unicomp	O
,	O
the	O
vast	O
majority	O
of	O
Model	B-Device
M	I-Device
keyboards	I-Device
feature	O
a	O
buckling	B-Device
spring	I-Device
key	O
design	O
and	O
many	O
have	O
fully	O
swappable	O
keycaps	B-Device
.	O
</s>
<s>
The	O
PC	B-Device
keyboard	I-Device
changed	O
over	O
the	O
years	O
,	O
often	O
at	O
the	O
launch	O
of	O
new	O
IBM	B-Device
PC	I-Device
versions	O
.	O
</s>
<s>
Name	O
Keys	O
Description	O
Image	O
Model	B-Device
F	I-Device
(	O
PC/XT	B-Device
)	O
83	O
Original	O
left-hand	O
side	O
function	B-Application
key	I-Application
(	O
F	O
key	O
)	O
columns	O
,	O
F1	O
through	O
F10	O
;	O
electronically	O
incompatible	B-Device
with	O
PC/AT	B-Operating_System
keyboard	B-Device
types	O
frameless|upright	O
=	O
0.65	O
|alt	O
=	O
83-key	O
PC/XT	B-Device
keyboard	B-Device
Introduced	O
with	O
original	O
IBM	B-Device
PC	I-Device
August	O
1981	O
.	O
</s>
<s>
Model	B-Device
F	I-Device
(	O
PC/AT	B-Operating_System
)	O
84	O
Additional	O
(	O
system	B-Device
request	I-Device
)	O
key	O
;	O
numerical	O
block	O
clearly	O
separated	O
from	O
main	O
keyboard	B-Device
;	O
added	O
indicator	O
LEDs	O
for	O
Caps/Scroll/Num	O
lock	O
frameless|upright	O
=	O
0.65	O
|alt	O
=	O
84-key	O
PC/AT	B-Operating_System
keyboard	B-Device
Introduced	O
August	O
1984	O
.	O
</s>
<s>
Model	B-Device
M	I-Device
(	O
Enhanced	O
)	O
Additional	O
navigation	O
and	O
control	B-Device
keys	I-Device
;	O
12	O
F	B-Application
keys	I-Application
in	O
separate	O
row	O
along	O
top	O
,	O
grouped	O
F1	O
–	O
4	O
,	O
F5	O
–	O
8	O
,	O
and	O
F9	O
–	O
12	O
.	O
</s>
<s>
Early	O
models	O
of	O
Enhanced	B-Device
keyboard	I-Device
(	O
notably	O
those	O
manufactured	O
by	O
Northgate	O
Ltd	O
.	O
)	O
maintained	O
the	O
layout	O
with	O
function	B-Application
keys	I-Application
on	O
the	O
left	O
side	O
,	O
arranged	O
in	O
two	O
columns	O
of	O
six	O
pairs	O
.	O
</s>
<s>
double-width	O
Backspace	O
key	O
(	O
spanning	O
E13	O
and	O
E14	O
)	O
frameless|upright	O
=	O
0.65	O
|alt	O
=	O
101-key	O
Enhanced	B-Device
keyboard	I-Device
Introduced	O
April	O
1986.IBM	O
.	O
</s>
<s>
IBM	B-Device
Enhanced	I-Device
Keyboard	I-Device
for	O
the	O
Personal	O
Computer	O
Announcement	O
Letter	O
.	O
</s>
<s>
additional	O
1	O
key	O
to	O
the	O
right	O
of	O
the	O
Left	B-Device
Shift	I-Device
key	I-Device
(	O
B00	O
)	O
frameless|upright	O
=	O
0.65	O
|alt	O
=	O
102-key	O
Enhanced	B-Device
keyboard	I-Device
Introduced	O
April	O
1986	O
.	O
</s>
<s>
additional	O
2	O
keys	O
:	O
one	O
to	O
the	O
left	O
(	O
A03	O
)	O
and	O
one	O
to	O
the	O
right	O
(	O
A07	O
)	O
of	O
the	O
space	B-Device
bar	I-Device
;	O
both	O
language	B-Device
input	I-Device
keys	I-Device
104	O
Brazilian	O
ABNT	O
NBR	O
10346	O
variant	O
2	O
(	O
alphanumeric	O
portion	O
)	O
and	O
10347	O
(	O
numeric	O
portion	O
)	O
.	O
</s>
<s>
the	O
key	O
at	O
E00	O
is	O
another	O
language	B-Device
input	I-Device
key	I-Device
but	O
exists	O
on	O
the	O
101-key	O
U.S.	O
layout	O
frameless|upright	O
=	O
0.65	O
|alt	O
=	O
106-key	O
Enhanced	B-Device
keyboard	I-Device
Windows	O
Additional	O
Windows	B-Device
key	I-Device
( ×2	O
)	O
and	O
Menu	B-Device
key	I-Device
added	O
(	O
one	O
Windows	B-Device
key	I-Device
to	O
the	O
right	O
of	O
the	O
left	O
control	B-Device
key	I-Device
,	O
the	O
other	O
and	O
the	O
Menu	B-Device
key	I-Device
to	O
the	O
left	O
of	O
the	O
right	O
control	B-Device
key	I-Device
)	O
.	O
</s>
<s>
Introduced	O
in	O
the	O
Microsoft	B-Device
Natural	I-Device
keyboard	I-Device
for	O
use	O
with	O
the	O
Windows	B-Application
95	I-Application
operating	B-General_Concept
system	I-General_Concept
.	O
</s>
<s>
Most	O
modern	O
PCs	O
,	O
whether	O
supplied	O
with	O
Microsoft	B-Application
Windows	I-Application
or	O
not	O
,	O
are	O
now	O
delivered	O
with	O
this	O
layout	O
.	O
</s>
<s>
Common	O
additions	O
to	O
the	O
standard	O
layouts	O
include	O
additional	O
power	B-Device
management	I-Device
keys	I-Device
,	O
volume	O
controls	O
,	O
media	O
player	O
controls	O
(	O
e.g.	O
</s>
<s>
"	O
Play/Pause	O
"	O
,	O
"	O
Previous	O
track	O
"	O
,	O
"	O
Next	O
track	O
)	O
and	O
miscellaneous	O
user-configurable	O
shortcuts	O
for	O
email	O
client	O
,	O
World	O
Wide	O
Web	O
browser	O
,	O
etc	O
.	O
</s>
<s>
The	O
IBM	B-Device
PC	I-Device
layout	O
,	O
particularly	O
the	O
Model	B-Device
M	I-Device
,	O
has	O
been	O
extremely	O
influential	O
,	O
and	O
today	O
most	O
keyboards	B-Device
use	O
some	O
variant	O
of	O
it	O
.	O
</s>
<s>
This	O
has	O
caused	O
problems	O
for	O
applications	O
developed	O
with	O
alternative	O
layouts	O
,	O
which	O
require	O
keys	O
that	O
are	O
in	O
awkward	O
positions	O
on	O
the	O
Model	B-Device
M	I-Device
layout	O
–	O
often	O
requiring	O
the	O
pinkie	O
to	O
operate	O
–	O
and	O
thus	O
require	O
remapping	O
for	O
comfortable	O
use	O
.	O
</s>
<s>
One	O
notable	O
example	O
is	O
the	O
escape	B-Device
key	I-Device
,	O
used	O
by	O
the	O
vi	B-Application
editor	I-Application
:	O
on	O
the	O
ADM-3A	B-Device
terminal	O
this	O
was	O
located	O
where	O
the	O
Tab	O
key	O
is	O
on	O
the	O
IBM	B-Device
PC	I-Device
,	O
but	O
on	O
the	O
IBM	B-Device
PC	I-Device
the	O
Escape	B-Device
key	I-Device
is	O
in	O
the	O
corner	O
;	O
this	O
is	O
typically	O
solved	O
by	O
remapping	O
Caps	B-Device
Lock	I-Device
to	O
Escape	O
.	O
</s>
<s>
Another	O
example	O
is	O
the	O
Emacs	B-Application
editor	O
,	O
which	O
makes	O
extensive	O
use	O
of	O
modifier	B-Device
keys	I-Device
,	O
and	O
uses	O
the	O
Control	B-Device
key	I-Device
more	O
than	O
the	O
meta	B-Device
key	I-Device
(	O
IBM	B-Device
PC	I-Device
instead	O
has	O
the	O
Alt	B-Device
key	I-Device
)	O
–	O
these	O
date	O
to	O
the	O
Knight	B-Device
keyboard	I-Device
,	O
which	O
had	O
the	O
Control	B-Device
key	I-Device
on	O
the	O
inside	O
of	O
the	O
Meta	B-Device
key	I-Device
,	O
opposite	O
to	O
the	O
Model	B-Device
M	I-Device
,	O
where	O
it	O
is	O
on	O
the	O
outside	O
of	O
the	O
Alt	B-Device
key	I-Device
;	O
and	O
to	O
the	O
space-cadet	B-Device
keyboard	I-Device
,	O
where	O
the	O
four	O
bucky	O
bit	O
keys	O
(	O
Control	O
,	O
Meta	O
,	O
Super	O
,	O
Hyper	O
)	O
are	O
in	O
a	O
row	O
,	O
allowing	O
easy	O
chording	O
to	O
press	O
several	O
,	O
unlike	O
on	O
the	O
Model	B-Device
M	I-Device
layout	O
.	O
</s>
<s>
This	O
results	O
in	O
the	O
"	O
Emacs	B-Application
pinky	O
"	O
problem	O
.	O
</s>
<s>
Although	O
PC	O
Magazine	O
praised	O
most	O
aspects	O
of	O
the	O
1981	O
IBM	B-Device
PC	I-Device
keyboard	I-Device
's	O
hardware	O
design	O
,	O
it	O
questioned	O
"	O
how	O
IBM	O
,	O
that	O
ultimate	O
pro	O
of	O
keyboard	B-Device
manufacture	O
,	O
could	O
put	O
the	O
left-hand	O
shift	B-Device
key	I-Device
at	O
the	O
awkward	O
reach	O
they	O
did	O
"	O
.	O
</s>
<s>
Byte	B-Application
columnist	O
Jerry	O
Pournelle	O
described	O
the	O
keyboard	B-Device
as	O
"	O
infuriatingly	O
excellent	O
"	O
.	O
</s>
<s>
He	O
praised	O
its	O
feel	O
but	O
complained	O
that	O
the	O
Shift	B-Device
and	O
other	O
keys	O
 '	O
locations	O
were	O
"	O
enough	O
to	O
make	O
a	O
saint	O
weep	O
"	O
,	O
and	O
denounced	O
the	O
trend	O
of	O
PC	O
compatible	O
computers	O
to	O
emulate	O
the	O
layout	O
but	O
not	O
the	O
feel	O
.	O
</s>
<s>
He	O
reported	O
that	O
the	O
layout	O
"	O
nearly	O
drove	O
"	O
science-fiction	O
editor	O
Jim	O
Baen	O
"	O
crazy	O
"	O
,	O
and	O
that	O
"	O
many	O
of	O
 [ Baen's ] 	O
authors	O
refused	O
to	O
work	O
with	O
that	O
keyboard	B-Device
"	O
so	O
could	O
not	O
submit	O
manuscripts	O
in	O
a	O
compatible	O
format	O
.	O
</s>
<s>
It	O
praised	O
the	O
keyboard	B-Device
as	O
"	O
bar	O
none	O
,	O
the	O
best	O
...	O
on	O
any	O
microcomputer	O
"	O
and	O
described	O
the	O
unusual	O
Shift	B-Device
key	I-Device
locations	O
as	O
"	O
minor	O
 [ problems ] 	O
compared	O
to	O
some	O
of	O
the	O
gigantic	O
mistakes	O
made	O
on	O
almost	O
every	O
other	O
microcomputer	O
keyboard	B-Device
"	O
.	O
</s>
<s>
"	O
I	O
was	O
n't	O
thrilled	O
with	O
the	O
placement	O
of	O
[	O
the	O
left	O
Shift	B-Device
and	O
Return ]	O
keys	O
,	O
either	O
"	O
,	O
IBM	O
's	O
Don	O
Estridge	O
stated	O
in	O
1983	O
.	O
</s>
<s>
The	O
PC	B-Device
keyboard	I-Device
with	O
its	O
various	O
keys	O
has	O
a	O
long	O
history	O
of	O
evolution	O
reaching	O
back	O
to	O
teletypewriters	O
.	O
</s>
<s>
In	O
addition	O
to	O
the	O
'	O
old	O
 '	O
standard	O
keys	O
,	O
the	O
PC	B-Device
keyboard	I-Device
has	O
accumulated	O
several	O
special	O
keys	O
over	O
the	O
years	O
.	O
</s>
<s>
Some	O
of	O
the	O
additions	O
have	O
been	O
inspired	O
by	O
the	O
opportunity	O
or	O
requirement	O
for	O
improving	O
user	O
productivity	O
with	O
general	O
office	O
application	B-Application
software	I-Application
,	O
while	O
other	O
slightly	O
more	O
general	O
keyboard	B-Device
additions	O
have	O
become	O
the	O
factory	O
standards	O
after	O
being	O
introduced	O
by	O
certain	O
operating	B-General_Concept
system	I-General_Concept
or	O
GUI	B-Application
software	O
vendors	O
such	O
as	O
Microsoft	O
.	O
</s>
<s>
The	O
Shift	B-Device
key	I-Device
in	O
typewriters	O
was	O
attached	O
to	O
a	O
lever	O
that	O
moved	O
the	O
character	O
types	O
so	O
that	O
the	O
uppercase	O
characters	O
could	O
be	O
printed	O
on	O
the	O
paper	O
.	O
</s>
<s>
Unlike	O
mechanical	O
typewriters	O
,	O
PC	B-Device
keyboards	I-Device
do	O
not	O
capitalize	O
all	O
letters	O
properly	O
when	O
both	O
shift	B-Device
keys	I-Device
are	O
engaged	O
simultaneously	O
.	O
</s>
<s>
selects	O
upper	O
case	O
,	O
or	O
if	O
shift	B-Device
is	O
pressed	O
,	O
lower	O
case	O
of	O
letters	O
.	O
</s>
<s>
In	O
mechanical	O
typewriters	O
,	O
it	O
worked	O
like	O
the	O
Shift	B-Device
key	I-Device
,	O
but	O
also	O
used	O
a	O
lock	O
to	O
keep	O
the	O
Shift	B-Device
key	I-Device
depressed	O
.	O
</s>
<s>
The	O
lock	O
was	O
released	O
by	O
pressing	O
the	O
Shift	B-Device
key	I-Device
.	O
</s>
<s>
ASCII	B-Protocol
keyboards	B-Device
were	O
labeled	O
CR	O
or	O
Return	O
.	O
</s>
<s>
produces	O
an	O
ASCII	B-Protocol
tab	O
character	O
,	O
moving	O
to	O
the	O
next	O
tab	O
stop	O
.	O
</s>
<s>
shifts	O
the	O
value	O
of	O
letters	O
and	O
numbers	O
from	O
the	O
ASCII	B-Protocol
graphics	O
range	O
,	O
down	O
into	O
the	O
ASCII	B-Protocol
control	O
characters	O
.	O
</s>
<s>
For	O
example	O
,	O
CTRL-S	O
is	O
XOFF	O
(	O
stops	O
many	O
programs	O
as	O
they	O
print	O
to	O
screen	O
)	O
CTRL-Q	O
is	O
XON	O
(	O
resume	O
printing	O
stopped	O
by	O
CTRL-S	O
)	O
.	O
</s>
<s>
produces	O
an	O
ASCII	B-Protocol
escape	B-Algorithm
character	I-Algorithm
.	O
</s>
<s>
Nowadays	O
the	O
key	O
does	O
not	O
produce	O
a	O
backspaceable	O
character	O
in	O
US/UK	O
keyboard	B-Device
layouts	O
,	O
and	O
is	O
used	O
for	O
'	O
not	O
 '	O
or	O
'	O
circa	O
 '	O
.	O
</s>
<s>
is	O
an	O
asterisk	B-Language
,	O
used	O
to	O
indicate	O
a	O
note	O
,	O
or	O
multiplication	O
.	O
</s>
<s>
Many	O
character	O
sets	O
break	O
it	O
in	O
the	O
middle	O
so	O
it	O
cannot	O
be	O
confused	O
with	O
the	O
numeral	O
"	O
1	O
"	O
or	O
the	O
letter	O
"	O
l	O
"	O
(	O
in	O
most	O
EBCDIC	B-Language
codepages	B-Device
,	O
vertical	O
bar	O
and	O
divided	O
vertical	O
bar	O
are	O
separate	O
characters	O
)	O
.	O
</s>
<s>
This	O
character	O
is	O
often	O
known	O
as	O
a	O
"	O
pipe	O
"	O
(	O
after	O
its	O
use	O
in	O
Unix	B-Application
shells	I-Application
)	O
or	O
a	O
"	O
fencepost	O
"	O
.	O
</s>
<s>
Function	B-Application
keys	I-Application
are	O
the	O
F-numbered	O
keys	O
.	O
</s>
<s>
Arrow	B-Device
keys	I-Device
(	O
,	O
,	O
,	O
)	O
move	O
the	O
cursor	O
on	O
the	O
screen	O
.	O
</s>
<s>
moves	O
the	O
cursor	O
to	O
the	O
end	B-Device
of	O
the	O
current	O
line	O
.	O
</s>
<s>
(	O
Insert	B-Device
)	O
originally	O
toggled	O
between	O
text	O
insertion	O
and	O
overwrite	O
modes	O
.	O
</s>
<s>
Importantly	O
,	O
it	O
is	O
involved	O
along	O
with	O
Ctrl	B-Device
and	O
Shift	B-Device
keys	I-Device
in	O
keyboard	B-Device
shortcuts	O
for	O
copy	O
(	O
)	O
and	O
paste	O
(	O
)	O
according	O
to	O
the	O
IBM	B-General_Concept
CUA	I-General_Concept
user	O
interface	O
guidelines	O
;	O
the	O
IBM	B-General_Concept
CUA	I-General_Concept
shortcuts	O
are	O
still	O
widely	O
supported	O
by	O
most	O
current	O
PC	O
operating	B-General_Concept
systems	I-General_Concept
,	O
and	O
many	O
PC	O
users	O
who	O
learned	O
those	O
shortcuts	O
between	O
the	O
late	O
1980s	O
and	O
the	O
early	O
1990s	O
may	O
still	O
find	O
them	O
more	O
natural	O
,	O
convenient	O
,	O
or	O
ergonomic	O
than	O
their	O
"	O
modern	O
"	O
Ctrl+	O
X/C/V	O
counterparts	O
,	O
given	O
the	O
close	O
proximity	O
of	O
the	O
Ctrl	B-Device
,	O
Shift	B-Device
and	O
Insert	B-Device
keys	I-Device
to	O
the	O
cursor	B-Device
movement	I-Device
keys	I-Device
.	O
</s>
<s>
This	O
particular	O
role	O
of	O
the	O
Insert	B-Device
key	I-Device
is	O
often	O
overlooked	O
by	O
modern-times	O
documentation	O
,	O
if	O
not	O
hardware	O
design	O
,	O
which	O
tend	O
to	O
attribute	O
to	O
"	O
Insert	B-Device
"	O
only	O
its	O
more	O
obvious	O
,	O
but	O
much	O
less	O
frequently	O
used	O
and	O
somewhat	O
obsolete	O
,	O
original	O
function	O
.	O
</s>
<s>
With	O
the	O
Alt	B-Device
key	I-Device
,	O
it	O
switched	O
to	O
SysRq	B-Device
,	O
a	O
different	O
keycode	O
.	O
</s>
<s>
toggles	O
the	O
state	O
of	O
the	O
numeric	B-Device
keypad	I-Device
.	O
</s>
<s>
When	O
on	O
,	O
it	O
is	O
a	O
10-key	B-Device
number	B-Device
pad	I-Device
similar	O
to	O
a	O
standard	O
calculator	O
.	O
</s>
<s>
The	O
key	O
continues	O
to	O
exist	O
on	O
keyboards	B-Device
with	O
separate	O
arrow	B-Device
keys	I-Device
to	O
accommodate	O
those	O
who	O
still	O
prefer	O
the	O
toggleable	O
keypad	O
.	O
</s>
<s>
IBM	O
documentation	O
described	O
it	O
as	O
"	O
inactive	O
"	O
,	O
and	O
the	O
key	O
's	O
purpose	O
was	O
a	O
mystery	O
even	O
to	O
keyboard	B-Device
manufacturers	O
.	O
</s>
<s>
Some	O
old	O
programs	O
could	O
disable	O
this	O
and	O
restart	O
at	O
the	O
top	O
of	O
the	O
window	O
when	O
scroll	B-Device
lock	I-Device
was	O
pressed	O
.	O
</s>
<s>
The	O
advantage	O
is	O
that	O
the	O
entire	O
screenful	O
of	O
text	O
does	O
not	O
shift	B-Device
,	O
making	O
it	O
easier	O
to	O
read	O
.	O
</s>
<s>
Scroll	B-Device
Lock	I-Device
was	O
also	O
used	O
to	O
lock	O
the	O
cursor	O
on	O
its	O
line	O
and	O
scroll	O
the	O
work	O
area	O
under	O
it	O
.	O
</s>
<s>
In	O
spreadsheets	O
such	O
as	O
Microsoft	B-Application
Excel	I-Application
,	O
it	O
locks	O
the	O
cell	O
pointer	O
on	O
the	O
current	O
cell	O
,	O
allowing	O
the	O
user	O
to	O
use	O
the	O
arrow	B-Device
keys	I-Device
to	O
move	O
the	O
view	O
window	O
without	O
moving	O
the	O
cell	O
pointer	O
.	O
</s>
<s>
On	O
some	O
consoles	O
(	O
such	O
as	O
the	O
Linux	B-Application
console	I-Application
)	O
,	O
it	O
prevents	O
scrolling	O
of	O
messages	O
until	O
another	O
key	O
combination	O
is	O
pressed	O
.	O
</s>
<s>
Many	O
hardware	O
KVM	B-Device
switches	I-Device
use	O
Scroll	B-Device
Lock	I-Device
to	O
switch	O
between	O
the	O
devices	O
they	O
control	O
.	O
</s>
<s>
In	O
combination	O
with	O
Ctrl	B-Device
,	O
it	O
produces	O
a	O
keycode	O
for	O
Break	O
.	O
</s>
<s>
In	O
combination	O
with	O
the	O
Windows	B-Device
key	I-Device
,	O
it	O
opens	O
the	O
System	O
Properties	O
window	O
in	O
Microsoft	B-Application
Windows	I-Application
environments	O
.	O
</s>
<s>
Alt	B-Device
plus	O
a	O
number	O
typed	O
on	O
the	O
numeric	B-Device
keypad	I-Device
produces	O
special	O
characters	O
;	O
see	O
Windows	O
Alt	B-Device
keycodes	O
.	O
</s>
<s>
(	O
also	O
known	O
as	O
the	O
"	O
super	O
"	O
key	O
)	O
is	O
a	O
quick	O
way	O
to	O
open	O
the	O
Start	O
menu	B-Device
in	O
Microsoft	B-Application
Windows	I-Application
's	O
standard	O
Explorer	O
shell	O
,	O
and	O
can	O
usually	O
be	O
configured	O
to	O
open	O
the	O
main	O
menu	B-Device
in	O
other	O
operating	B-General_Concept
systems	I-General_Concept
.	O
</s>
<s>
In	O
Microsoft	B-Application
Windows	I-Application
,	O
the	O
Windows	B-Device
key	I-Device
can	O
also	O
be	O
used	O
in	O
combination	O
with	O
other	O
keys	O
to	O
perform	O
desktop-related	O
actions	O
(	O
e.g.	O
</s>
<s>
When	O
connected	O
to	O
a	O
Macintosh	B-Device
computer	I-Device
,	O
the	O
Windows	B-Device
key	I-Device
behaves	O
like	O
the	O
key	O
.	O
</s>
<s>
The	O
key	O
brings	O
up	O
the	O
active	O
application	O
's	O
context	O
menu	B-Device
,	O
similar	O
to	O
right-clicking	O
.	O
</s>
<s>
is	O
often	O
used	O
in	O
combination	O
with	O
other	O
keys	O
to	O
print	O
special	O
characters	O
like	O
the	O
backslash	O
on	O
non-English	O
keyboards	B-Device
.	O
</s>
<s>
may	O
be	O
present	O
on	O
compact	O
keyboards	B-Device
such	O
as	O
those	O
built	O
into	O
laptop	O
computers	O
.	O
</s>
<s>
When	O
depressed	O
in	O
combination	O
with	O
other	O
keys	O
,	O
it	O
either	O
enables	O
the	O
user	O
to	O
access	O
key	O
functions	O
that	O
do	O
not	O
have	O
dedicated	O
keys	O
on	O
the	O
compact	O
keyboard	B-Device
(	O
such	O
as	O
the	O
numeric	B-Device
keypad	I-Device
simulation	O
block	O
)	O
,	O
or	O
it	O
controls	O
hardware	O
functions	O
such	O
as	O
switching	O
between	O
the	O
built-in	O
screen	O
and	O
an	O
external	O
display	O
,	O
changing	O
screen	O
brightness	O
,	O
or	O
changing	O
speaker	O
volume	O
.	O
</s>
<s>
These	O
secondary	O
meanings	O
are	O
usually	O
indicated	O
with	O
text	O
or	O
symbols	O
of	O
a	O
different	O
color	O
printed	O
on	O
the	O
key	O
,	O
with	O
the	O
'	O
Fn	B-Device
 '	O
key	O
text	O
having	O
that	O
same	O
color	O
.	O
</s>
<s>
on	O
some	O
keyboards	B-Device
.	O
</s>
<s>
It	O
is	O
usually	O
on	O
the	O
right	O
side	O
of	O
the	O
right	B-Device
Shift	I-Device
key	I-Device
.	O
</s>
<s>
When	O
depressed	O
in	O
combination	O
with	O
a	O
function	B-Application
key	I-Application
it	O
sets	O
the	O
key	O
repeat	O
rate	O
.	O
</s>
<s>
System	O
Connector	O
Pinout	O
Transmission	O
Protocol	O
Command	B-Device
Strings	O
Image	O
PC	O
(	O
Type	O
1	O
)	O
International	O
Business	O
Machines	O
Corporation	O
(	O
1983	O
)	O
:	O
IBM	B-Device
Personal	I-Device
Computer	I-Device
XT	I-Device
Technical	O
Reference	O
Manual	O
,	O
pages	O
D-12	O
to	O
D-13	O
.	O
</s>
<s>
4	O
Groundsync	O
field	O
plus8-bit	O
bytes	B-Application
as	O
packets(HANDSHAKE, TOKEN, DATA, Special packets )	O
,	O
least-significant	O
bit	O
first	O
.	O
</s>
