<s>
The	O
LK201	B-Device
is	O
a	O
detachable	O
computer	O
keyboard	O
introduced	O
by	O
Digital	O
Equipment	O
Corporation	O
of	O
Maynard	O
,	O
Massachusetts	O
in	O
1982	O
.	O
</s>
<s>
It	O
was	O
first	O
used	O
by	O
Digital	O
's	O
VT220	B-Device
ANSI/ASCII	O
terminal	O
and	O
was	O
subsequently	O
used	O
by	O
the	O
Rainbow-100	B-Device
,	O
DECmate-II	O
,	O
and	O
Pro-350	B-Device
microcomputers	O
and	O
many	O
of	O
Digital	O
's	O
computer	O
workstations	O
such	O
as	O
the	O
VAXstation	B-Device
and	O
DECstation	B-Device
families	O
.	O
</s>
<s>
The	O
keyboard	O
layout	O
was	O
new	O
at	O
the	O
time	O
,	O
adding	O
a	O
set	O
of	O
cursor	O
and	O
miscellaneous	O
keys	O
between	O
the	O
main	O
keyboard	O
and	O
the	O
numeric	B-Device
keypad	I-Device
.	O
</s>
<s>
The	O
cursor	B-Device
keys	I-Device
were	O
arranged	O
in	O
what	O
has	O
now	O
become	O
the	O
standard	O
"	O
Inverted	O
T	O
"	O
arrangement	O
seen	O
on	O
essentially	O
all	O
contemporary	O
full-sized	O
computer	O
keyboards	O
.	O
</s>
<s>
The	O
keyboard	O
also	O
added	O
a	O
Compose	B-Device
key	I-Device
to	O
allow	O
typing	O
of	O
all	O
of	O
the	O
characters	O
in	O
the	O
terminal	O
's	O
extended	O
character	O
set	O
using	O
two-stroke	O
mnemonics	O
,	O
for	O
instance	O
produced	O
.	O
</s>
<s>
An	O
LED	O
on	O
the	O
keyboard	O
indicated	O
an	O
ongoing	O
compose	B-Device
sequence	I-Device
.	O
</s>
<s>
Ergonomic	O
considerations	O
caused	O
the	O
keyboard	O
to	O
be	O
designed	O
with	O
a	O
very	O
low	O
profile	O
;	O
it	O
was	O
very	O
thin	O
,	O
especially	O
when	O
compared	O
to	O
the	O
keyboard	O
used	O
on	O
the	O
VT100	B-Device
.	O
</s>
<s>
The	O
keyboard	O
connected	O
using	O
a	O
modular	B-Architecture
connector	I-Architecture
over	O
which	O
flowed	O
power	O
and	O
asynchronous	O
serial	O
data	O
.	O
</s>
<s>
At	O
the	O
time	O
of	O
its	O
introduction	O
,	O
the	O
differences	O
between	O
the	O
new	O
layout	O
and	O
the	O
traditional	O
Teletype	B-Application
Model	I-Application
33	I-Application
and	O
VT100	B-Device
layouts	O
proved	O
disruptive	O
,	O
but	O
the	O
LK201	B-Device
's	O
key	O
arrangement	O
was	O
emulated	O
by	O
the	O
even	O
more	O
successful	O
Model	B-Device
M	I-Device
keyboard	I-Device
and	O
through	O
it	O
became	O
the	O
de	O
facto	O
standard	O
for	O
all	O
full-sized	O
computer	O
keyboards	O
.	O
</s>
<s>
Today	O
's	O
standard	O
layout	O
differs	O
primarily	O
in	O
the	O
restoration	O
of	O
the	O
Escape	B-Device
Key	I-Device
found	O
on	O
the	O
VT100	B-Device
and	O
that	O
the	O
numeric	B-Device
keypad	I-Device
has	O
two	O
double-height	O
keys	O
instead	O
of	O
one	O
,	O
decreasing	O
the	O
number	B-Device
pad	I-Device
keys	O
from	O
18	O
to	O
17	O
.	O
</s>
<s>
The	O
VT220	B-Device
Compose	B-Device
key	I-Device
would	O
survive	O
in	O
the	O
European	O
ISO	O
standard	O
but	O
not	O
in	O
the	O
U.S.	O
ANSI	O
standard	O
.	O
</s>
<s>
Follow-on	O
keyboards	O
from	O
Digital	O
refined	O
the	O
design	O
introduced	O
with	O
the	O
LK201	B-Device
.	O
</s>
<s>
One	O
notable	O
departure	O
from	O
the	O
basic	O
LK201	B-Device
design	O
was	O
a	O
Unix-oriented	O
keyboard	O
,	O
the	O
LK421	B-Device
,	O
that	O
omitted	O
the	O
added	O
middle	O
group	O
of	O
cursor	O
and	O
miscellaneous	O
function	O
keys	O
but	O
included	O
a	O
dedicated	O
Escape	B-Device
Key	I-Device
.	O
</s>
<s>
Many	O
Unix	B-Application
users	O
preferred	O
a	O
narrower	O
,	O
ASCII-oriented	O
keyboard	O
rather	O
than	O
the	O
rather-wide	O
LK201	B-Device
arrangement	O
and	O
the	O
Escape	B-Device
Key	I-Device
was	O
essential	O
for	O
several	O
popular	O
Unix	B-Application
editors	O
.	O
</s>
