<s>
Extended	B-Protocol
ASCII	I-Protocol
is	O
a	O
repertoire	O
of	O
character	B-General_Concept
encodings	I-General_Concept
that	O
include	O
(	O
most	O
of	O
)	O
the	O
original	O
96	O
ASCII	B-Protocol
character	I-Protocol
set	I-Protocol
,	O
plus	O
up	O
to	O
128	O
additional	O
characters	O
.	O
</s>
<s>
There	O
is	O
no	O
formal	O
definition	O
of	O
"	O
extended	B-Protocol
ASCII	I-Protocol
"	O
,	O
and	O
even	O
use	O
of	O
the	O
term	O
is	O
sometimes	O
criticized	O
,	O
because	O
it	O
can	O
be	O
mistakenly	O
interpreted	O
to	O
mean	O
that	O
the	O
American	O
National	O
Standards	O
Institute	O
(	O
ANSI	O
)	O
had	O
updated	O
its	O
standard	O
to	O
include	O
more	O
characters	O
,	O
or	O
that	O
the	O
term	O
identifies	O
a	O
single	O
unambiguous	O
encoding	O
,	O
neither	O
of	O
which	O
is	O
the	O
case	O
.	O
</s>
<s>
The	O
ISO	O
standard	O
ISO	O
8859	O
was	O
the	O
first	O
international	O
standard	O
to	O
formalise	O
a	O
(	O
limited	O
)	O
expansion	O
of	O
the	O
ASCII	B-Protocol
character	I-Protocol
set	I-Protocol
:	O
of	O
the	O
many	O
language	O
variants	O
it	O
encoded	O
,	O
ISO	O
8859-1	O
(	O
"	O
ISO	O
Latin	O
1	O
"	O
)	O
which	O
supports	O
most	O
Western	O
European	O
languages	O
is	O
best	O
known	O
in	O
the	O
West	O
.	O
</s>
<s>
There	O
are	O
many	O
other	O
extended	B-Protocol
ASCII	I-Protocol
encodings	O
(	O
more	O
than	O
220	O
DOS	B-Device
and	O
Windows	O
codepages	B-Device
)	O
.	O
</s>
<s>
EBCDIC	B-Language
(	O
"	O
the	O
other	O
"	O
major	O
character	B-General_Concept
code	I-General_Concept
)	O
likewise	O
developed	O
many	O
extended	O
variants	O
(	O
more	O
than	O
186	O
EBCDIC	B-Language
codepages	B-Device
)	O
over	O
the	O
decades	O
.	O
</s>
<s>
The	O
technology	O
has	O
largely	O
been	O
rendered	O
technically	O
obsolete	O
by	O
Unicode	O
,	O
which	O
has	O
code	O
points	O
for	O
all	O
the	O
characters	O
encoded	O
in	O
the	O
various	O
attempts	O
to	O
extend	O
ASCII	B-Protocol
.	O
</s>
<s>
All	O
modern	O
operating	B-General_Concept
systems	I-General_Concept
use	O
this	O
technology	O
.	O
</s>
<s>
ASCII	B-Protocol
was	O
designed	O
in	O
the	O
1960s	O
for	O
teleprinters	O
and	O
telegraphy	O
,	O
and	O
some	O
computing	O
.	O
</s>
<s>
They	O
were	O
typewriter-derived	O
impact	O
printers	O
,	O
and	O
could	O
only	O
print	O
a	O
fixed	O
set	O
of	O
glyphs	B-Application
,	O
which	O
were	O
cast	O
into	O
a	O
metal	O
type	O
element	O
or	O
elements	O
;	O
this	O
also	O
encouraged	O
a	O
minimum	O
set	O
of	O
glyphs	B-Application
.	O
</s>
<s>
Seven-bit	B-Protocol
ASCII	I-Protocol
improved	O
over	O
prior	O
five	O
-	O
and	O
six-bit	O
codes	O
.	O
</s>
<s>
Of	O
the	O
27	O
=	O
128	O
codes	O
,	O
33	O
were	O
used	O
for	O
controls	O
,	O
and	O
95	O
carefully	O
selected	O
printable	O
characters	O
(	O
94	O
glyphs	B-Application
and	O
one	O
space	O
)	O
,	O
which	O
include	O
the	O
English	O
alphabet	O
(	O
uppercase	O
and	O
lowercase	O
)	O
,	O
digits	O
,	O
and	O
31	O
punctuation	O
marks	O
and	O
symbols	O
:	O
all	O
of	O
the	O
symbols	O
on	O
a	O
standard	O
US	O
typewriter	O
plus	O
a	O
few	O
selected	O
for	O
programming	O
tasks	O
.	O
</s>
<s>
Some	O
popular	O
peripherals	O
only	O
implemented	O
a	O
64-printing-character	O
subset	O
:	O
Teletype	B-Application
Model	I-Application
33	I-Application
could	O
not	O
transmit	O
"	O
a	O
"	O
through	O
"	O
z	O
"	O
or	O
five	O
less-common	O
symbols	O
("`"	O
,	O
"	O
{	O
"	O
,	O
"	O
|	O
"	O
,	O
"	O
}	O
"	O
,	O
and	O
"	O
~	O
"	O
)	O
.	O
</s>
<s>
The	O
ASCII	B-Protocol
character	I-Protocol
set	I-Protocol
is	O
barely	O
large	O
enough	O
for	O
US	O
English	O
use	O
and	O
lacks	O
many	O
glyphs	B-Application
common	O
in	O
typesetting	O
,	O
and	O
far	O
too	O
small	O
for	O
universal	O
use	O
.	O
</s>
<s>
For	O
example	O
,	O
ASCII	B-Protocol
lacks	O
"	O
÷	O
"	O
,	O
so	O
most	O
programming	O
languages	O
use	O
"	O
/	O
"	O
to	O
indicate	O
division	O
.	O
</s>
<s>
ASCII	B-Protocol
's	O
English	O
alphabet	O
almost	O
accommodates	O
European	O
languages	O
,	O
if	O
accented	O
letters	O
are	O
replaced	O
by	O
non-accented	O
letters	O
or	O
two-character	O
approximations	O
.	O
</s>
<s>
Modified	O
variants	O
of	O
7-bit	B-Protocol
ASCII	I-Protocol
appeared	O
promptly	O
,	O
trading	O
some	O
lesser-used	O
symbols	O
for	O
highly	O
desired	O
symbols	O
or	O
letters	O
,	O
such	O
as	O
replacing	O
"	O
#	O
"	O
with	O
"	O
£	O
"	O
on	O
UK	O
Teletypes	O
,	O
"	O
\	O
 "	O
with	O
"	O
¥	O
"	O
in	O
Japan	O
or	O
"	O
₩	O
"	O
in	O
Korea	O
,	O
etc	O
.	O
</s>
<s>
Programming	O
languages	O
however	O
had	O
assigned	O
meaning	O
to	O
many	O
of	O
the	O
replaced	O
characters	O
,	O
work-arounds	O
were	O
devised	O
such	O
as	O
C	B-Language
three-character	B-Language
sequences	I-Language
"	O
?	O
</s>
<s>
Schemes	O
were	O
also	O
devised	O
so	O
that	O
two	O
letters	O
could	O
be	O
overprinted	O
(	O
often	O
with	O
the	O
backspace	B-Device
control	O
between	O
them	O
)	O
to	O
produce	O
accented	O
letters	O
.	O
</s>
<s>
When	O
computers	O
and	O
peripherals	O
standardized	O
on	O
eight-bit	O
bytes	B-Application
in	O
the	O
1970s	O
,	O
it	O
became	O
obvious	O
that	O
computers	O
and	O
software	O
could	O
handle	O
text	O
that	O
uses	O
256-character	O
sets	O
at	O
almost	O
no	O
additional	O
cost	O
in	O
programming	O
,	O
and	O
no	O
additional	O
cost	O
for	O
storage	O
.	O
</s>
<s>
(	O
Assuming	O
that	O
the	O
unused	O
8th	O
bit	O
of	O
each	O
byte	B-Application
was	O
not	O
reused	O
in	O
some	O
way	O
,	O
such	O
as	O
error	O
checking	O
,	O
Boolean	O
fields	O
,	O
or	O
packing	O
8	O
characters	O
into	O
7	O
bytes	B-Application
.	O
)	O
</s>
<s>
This	O
would	O
allow	O
ASCII	B-Protocol
to	O
be	O
used	O
unchanged	O
and	O
provide	O
128	O
more	O
characters	O
.	O
</s>
<s>
Many	O
manufacturers	O
devised	O
8-bit	O
character	B-General_Concept
sets	I-General_Concept
consisting	O
of	O
ASCII	B-Protocol
plus	O
up	O
to	O
128	O
of	O
the	O
unused	O
codes	O
.	O
</s>
<s>
128	O
additional	O
characters	O
is	O
still	O
not	O
enough	O
to	O
cover	O
all	O
purposes	O
,	O
all	O
languages	O
,	O
or	O
even	O
all	O
European	O
languages	O
,	O
so	O
the	O
emergence	O
of	O
many	O
proprietary	O
and	O
national	O
ASCII-derived	O
8-bit	O
character	B-General_Concept
sets	I-General_Concept
was	O
inevitable	O
.	O
</s>
<s>
Translating	O
between	O
these	O
sets	O
(	O
transcoding	B-Algorithm
)	O
is	O
complex	O
(	O
especially	O
if	O
a	O
character	O
is	O
not	O
in	O
both	O
sets	O
)	O
;	O
and	O
was	O
often	O
not	O
done	O
,	O
producing	O
mojibake	O
(	O
semi-readable	O
resulting	O
text	O
,	O
often	O
users	O
learned	O
how	O
to	O
manually	O
decode	O
it	O
)	O
.	O
</s>
<s>
Various	O
proprietary	O
modifications	O
and	O
extensions	O
of	O
ASCII	B-Protocol
appeared	O
on	O
non-EBCDIC	O
mainframe	B-Architecture
computers	I-Architecture
and	O
minicomputers	B-Architecture
,	O
especially	O
in	O
universities	O
.	O
</s>
<s>
Hewlett-Packard	O
started	O
to	O
add	O
European	O
characters	O
to	O
their	O
extended	O
7-bit	O
/	O
8-bit	B-Protocol
ASCII	I-Protocol
character	B-General_Concept
set	I-General_Concept
HP	O
Roman	O
Extension	O
around	O
1978/1979	O
for	O
use	O
with	O
their	O
workstations	O
,	O
terminals	O
and	O
printers	O
.	O
</s>
<s>
This	O
later	O
evolved	O
into	O
the	O
widely	O
used	O
regular	O
8-bit	O
character	B-General_Concept
sets	I-General_Concept
HP	O
Roman-8	O
and	O
HP	O
Roman-9	O
(	O
as	O
well	O
as	O
a	O
number	O
of	O
variants	O
)	O
.	O
</s>
<s>
Atari	O
and	O
Commodore	O
home	O
computers	O
added	O
many	O
graphic	O
symbols	O
to	O
their	O
non-standard	O
ASCII	B-Protocol
(	O
Respectively	O
,	O
ATASCII	B-Protocol
and	O
PETSCII	B-Protocol
,	O
based	O
on	O
the	O
original	O
ASCII	B-Protocol
standard	O
of	O
1963	O
)	O
.	O
</s>
<s>
The	O
TRS-80	B-Device
character	I-Device
set	I-Device
for	O
the	O
TRS-80	B-Device
home	O
computer	O
added	O
64	O
semigraphics	B-Data_Structure
characters	O
(	O
0x80	O
through	O
0xBF	O
)	O
that	O
implemented	O
low-resolution	O
block	O
graphics	O
.	O
</s>
<s>
IBM	O
introduced	O
eight-bit	O
extended	B-Protocol
ASCII	I-Protocol
codes	O
on	O
the	O
original	O
IBM	B-Device
PC	I-Device
and	O
later	O
produced	O
variations	O
for	O
different	O
languages	O
and	O
cultures	O
.	O
</s>
<s>
IBM	O
called	O
such	O
character	B-General_Concept
sets	I-General_Concept
code	O
pages	O
and	O
assigned	O
numbers	O
to	O
both	O
those	O
they	O
themselves	O
invented	O
as	O
well	O
as	O
many	O
invented	O
and	O
used	O
by	O
other	O
manufacturers	O
.	O
</s>
<s>
Accordingly	O
,	O
character	B-General_Concept
sets	I-General_Concept
are	O
very	O
often	O
indicated	O
by	O
their	O
IBM	O
code	O
page	O
number	O
.	O
</s>
<s>
In	O
ASCII-compatible	O
code	O
pages	O
,	O
the	O
lower	O
128	O
characters	O
maintained	O
their	O
standard	O
US-ASCII	B-Protocol
values	O
,	O
and	O
different	O
pages	O
(	O
or	O
sets	O
of	O
characters	O
)	O
could	O
be	O
made	O
available	O
in	O
the	O
upper	O
128	O
characters	O
.	O
</s>
<s>
DOS	B-Device
computers	O
built	O
for	O
the	O
North	O
American	O
market	O
,	O
for	O
example	O
,	O
used	O
code	O
page	O
437	O
,	O
which	O
included	O
accented	O
characters	O
needed	O
for	O
French	O
,	O
German	O
,	O
and	O
a	O
few	O
other	O
European	O
languages	O
,	O
as	O
well	O
as	O
some	O
graphical	O
line-drawing	O
characters	O
.	O
</s>
<s>
The	O
larger	O
character	B-General_Concept
set	I-General_Concept
made	O
it	O
possible	O
to	O
create	O
documents	O
in	O
a	O
combination	O
of	O
languages	O
such	O
as	O
English	O
and	O
French	O
(	O
though	O
French	O
computers	O
usually	O
use	O
code	O
page	O
850	O
)	O
,	O
but	O
not	O
,	O
for	O
example	O
,	O
in	O
English	O
and	O
Greek	O
(	O
which	O
required	O
code	O
page	O
737	O
)	O
.	O
</s>
<s>
Apple	O
Computer	O
introduced	O
their	O
own	O
eight-bit	O
extended	B-Protocol
ASCII	I-Protocol
codes	O
in	O
Mac	B-Application
OS	I-Application
,	O
such	O
as	O
Mac	B-Application
OS	I-Application
Roman	O
.	O
</s>
<s>
The	O
Apple	O
LaserWriter	O
also	O
introduced	O
the	O
Postscript	O
character	B-General_Concept
set	I-General_Concept
.	O
</s>
<s>
Digital	O
Equipment	O
Corporation	O
(	O
DEC	O
)	O
developed	O
the	O
Multinational	O
Character	B-General_Concept
Set	I-General_Concept
,	O
which	O
had	O
fewer	O
characters	O
but	O
more	O
letter	O
and	O
diacritic	O
combinations	O
.	O
</s>
<s>
It	O
was	O
supported	O
by	O
the	O
VT220	B-Device
and	O
later	O
DEC	O
computer	B-General_Concept
terminals	I-General_Concept
.	O
</s>
<s>
This	O
later	O
became	O
the	O
basis	O
for	O
other	O
character	B-General_Concept
sets	I-General_Concept
such	O
as	O
the	O
Lotus	O
International	B-General_Concept
Character	I-General_Concept
Set	I-General_Concept
(	O
LICS	O
)	O
,	O
ECMA-94	O
and	O
ISO	O
8859-1	O
.	O
</s>
<s>
Eventually	O
,	O
ISO	O
released	O
this	O
standard	O
as	O
ISO	O
8859	O
describing	O
its	O
own	O
set	O
of	O
eight-bit	B-Protocol
ASCII	I-Protocol
extensions	O
.	O
</s>
<s>
One	O
notable	O
way	O
in	O
which	O
ISO	O
character	B-General_Concept
sets	I-General_Concept
differ	O
from	O
code	O
pages	O
is	O
that	O
the	O
character	O
positions	O
128	O
to	O
159	O
,	O
corresponding	O
to	O
ASCII	B-Protocol
control	O
characters	O
with	O
the	O
high-order	O
bit	O
set	O
,	O
are	O
specifically	O
unused	O
and	O
undefined	O
in	O
the	O
ISO	O
standards	O
,	O
though	O
they	O
had	O
often	O
been	O
used	O
for	O
printable	O
characters	O
in	O
proprietary	O
code	O
pages	O
,	O
a	O
breaking	O
of	O
ISO	O
standards	O
that	O
was	O
almost	O
universal	O
.	O
</s>
<s>
Code	O
page	O
1252	O
is	O
the	O
standard	O
character	B-General_Concept
encoding	I-General_Concept
of	O
western	O
European	O
language	O
versions	O
of	O
Microsoft	B-Application
Windows	I-Application
,	O
including	O
English	O
versions	O
.	O
</s>
<s>
ISO	O
8859-1	O
is	O
the	O
common	O
8-bit	O
character	B-General_Concept
encoding	I-General_Concept
used	O
by	O
the	O
X	B-Operating_System
Window	I-Operating_System
System	I-Operating_System
,	O
and	O
most	O
Internet	O
standards	O
used	O
it	O
before	O
Unicode	O
.	O
</s>
<s>
In	O
order	O
to	O
correctly	O
interpret	O
and	O
display	O
text	O
data	O
(	O
sequences	O
of	O
characters	O
)	O
that	O
includes	O
extended	O
codes	O
,	O
hardware	O
and	O
software	O
that	O
reads	O
or	O
receives	O
the	O
text	O
must	O
use	O
the	O
specific	O
extended	B-Protocol
ASCII	I-Protocol
encoding	O
that	O
applies	O
to	O
it	O
.	O
</s>
<s>
Applying	O
the	O
wrong	O
encoding	O
causes	O
irrational	O
substitution	O
of	O
many	O
or	O
all	O
extended	B-Protocol
characters	I-Protocol
in	O
the	O
text	O
.	O
</s>
<s>
When	O
text	O
is	O
transferred	O
between	O
computers	O
that	O
use	O
different	O
operating	B-General_Concept
systems	I-General_Concept
,	O
software	O
,	O
and	O
encodings	O
,	O
applying	O
the	O
wrong	O
encoding	O
can	O
be	O
commonplace	O
.	O
</s>
<s>
Because	O
the	O
full	O
English	O
alphabet	O
and	O
the	O
most-used	O
characters	O
in	O
English	O
are	O
included	O
in	O
the	O
seven-bit	O
code	O
points	O
of	O
ASCII	B-Protocol
,	O
which	O
are	O
common	O
to	O
all	O
encodings	O
(	O
even	O
most	O
proprietary	O
encodings	O
)	O
,	O
English-language	O
text	O
is	O
less	O
damaged	O
by	O
interpreting	O
it	O
with	O
the	O
wrong	O
encoding	O
,	O
but	O
text	O
in	O
other	O
languages	O
can	O
display	O
as	O
mojibake	O
(	O
complete	O
nonsense	O
)	O
.	O
</s>
<s>
Because	O
many	O
Internet	O
standards	O
use	O
ISO	O
8859-1	O
,	O
and	O
because	O
Microsoft	B-Application
Windows	I-Application
(	O
using	O
the	O
code	O
page	O
1252	O
superset	O
of	O
ISO	O
8859-1	O
)	O
is	O
the	O
dominant	O
operating	B-General_Concept
system	I-General_Concept
for	O
personal	O
computers	O
today	O
,	O
unannounced	O
use	O
of	O
ISO	O
8859-1	O
is	O
quite	O
commonplace	O
,	O
and	O
may	O
generally	O
be	O
assumed	O
unless	O
there	O
are	O
indications	O
otherwise	O
.	O
</s>
<s>
Many	O
communications	O
protocols	O
,	O
most	O
importantly	O
SMTP	B-Protocol
and	O
HTTP	B-Protocol
,	O
require	O
the	O
character	B-General_Concept
encoding	I-General_Concept
of	O
content	O
to	O
be	O
tagged	O
with	O
IANA-assigned	O
character	B-General_Concept
set	I-General_Concept
identifiers	O
.	O
</s>
<s>
For	O
programming	O
languages	O
and	O
document	O
languages	O
such	O
as	O
C	B-Language
and	O
HTML	B-Language
,	O
the	O
principle	O
of	O
Extended	B-Protocol
ASCII	I-Protocol
is	O
important	O
,	O
since	O
it	O
enables	O
many	O
different	O
encodings	O
and	O
therefore	O
many	O
human	O
languages	O
to	O
be	O
supported	O
with	O
little	O
extra	O
programming	O
effort	O
in	O
the	O
software	O
that	O
interprets	O
the	O
computer-readable	O
language	O
files	O
.	O
</s>
<s>
The	O
principle	O
of	O
Extended	B-Protocol
ASCII	I-Protocol
means	O
that	O
:	O
</s>
<s>
all	O
ASCII	B-Protocol
bytes	B-Application
(	O
0x00	O
to	O
0x7F	O
)	O
have	O
the	O
same	O
meaning	O
in	O
all	O
variants	O
of	O
extended	B-Protocol
ASCII	I-Protocol
,	O
</s>
<s>
bytes	B-Application
that	O
are	O
not	O
ASCII	B-Protocol
bytes	B-Application
are	O
used	O
only	O
for	O
free	O
text	O
and	O
not	O
for	O
tags	O
,	O
keywords	O
,	O
or	O
other	O
features	O
that	O
have	O
special	O
meaning	O
to	O
the	O
interpreting	O
software	O
.	O
</s>
<s>
A	O
computer	O
language	O
that	O
supports	O
Extended	B-Protocol
ASCII	I-Protocol
can	O
also	O
support	O
UTF-8	O
without	O
any	O
changes	O
,	O
this	O
was	O
a	O
major	O
factor	O
in	O
UTF-8	O
'	O
s	O
popularity	O
.	O
</s>
