<s>
The	O
ZX80	B-Language
character	I-Language
set	I-Language
is	O
the	O
character	B-General_Concept
encoding	I-General_Concept
used	O
by	O
the	O
Sinclair	O
Research	O
ZX80	B-Operating_System
microcomputer	B-Architecture
with	O
its	O
original	O
4K	O
BASIC	B-Language
ROM	B-Device
.	O
</s>
<s>
The	O
encoding	O
uses	O
one	O
byte	B-Application
per	O
character	O
for	O
256	O
code	O
points	O
.	O
</s>
<s>
It	O
has	O
no	O
relationship	O
with	O
previously	O
established	O
ones	O
like	O
ASCII	B-Protocol
or	O
EBCDIC	B-Language
,	O
but	O
it	O
is	O
related	O
though	O
not	O
identical	O
to	O
the	O
character	B-Language
set	I-Language
of	I-Language
the	I-Language
successor	I-Language
ZX81	I-Language
.	O
</s>
<s>
The	O
character	B-General_Concept
set	I-General_Concept
has	O
64	O
unique	O
glyphs	O
present	O
at	O
code	O
points	O
0	O
–	O
63	O
.	O
</s>
<s>
With	O
the	O
most	O
significant	O
bit	O
set	O
the	O
character	O
is	O
generated	O
in	O
inverse	B-General_Concept
video	I-General_Concept
;	O
corresponding	O
to	O
code	O
points	O
128	O
–	O
191	O
.	O
</s>
<s>
The	O
remaining	O
code	O
points	O
(	O
64	O
–	O
127	O
and	O
192	O
–	O
255	O
)	O
are	O
used	O
as	O
control	O
characters	O
or	O
Sinclair	B-Language
BASIC	I-Language
keywords	O
,	O
while	O
some	O
are	O
unused	O
.	O
</s>
<s>
Together	O
with	O
the	O
11	O
inverse	B-General_Concept
video	I-General_Concept
versions	O
these	O
22	O
code	O
points	O
provide	O
every	O
combination	O
of	O
the	O
character	O
cell	O
divided	O
into	O
2×2	O
black-and-white	O
block	O
pixels	O
for	O
low-resolution	O
64×48	O
pixel	O
graphics	O
,	O
or	O
into	O
1×2	O
black	O
,	O
white	O
or	O
dithered	O
gray	O
wide	O
block	O
pixels	O
for	O
a	O
32×48	O
resolution	O
.	O
</s>
<s>
Code	O
point	O
1	O
is	O
the	O
double-quote	O
(	O
"	O
)	O
character	O
when	O
used	O
in	O
the	O
display	O
file	O
,	O
but	O
uniquely	O
to	O
the	O
ZX80	B-Operating_System
it	O
is	O
used	O
internally	O
as	O
the	O
string	O
terminator	O
character	O
so	O
the	O
BASIC	B-Language
function	O
CHR$( 1	O
)	O
returns	O
a	O
null	O
string	O
;	O
CHR$( 212	O
)	O
translates	O
to	O
the	O
printable	O
"	O
character	O
.	O
</s>
<s>
The	O
8K	O
BASIC	B-Language
ROM	B-Device
of	O
the	O
follow-up	O
ZX81	O
model	O
was	O
also	O
available	O
as	O
an	O
upgrade	O
for	O
the	O
ZX80	B-Operating_System
,	O
replacing	O
its	O
integer-only	O
4K	O
BASIC	B-Language
ROM	B-Device
.	O
</s>
<s>
It	O
introduced	O
the	O
modified	O
ZX81	B-Language
character	I-Language
set	I-Language
which	O
has	O
mostly	O
the	O
same	O
code	O
points	O
,	O
e.g.	O
</s>
<s>
for	O
A-Z	O
and	O
0-9	O
,	O
but	O
the	O
code	O
points	O
are	O
different	O
for	O
the	O
block	O
graphics	O
characters	O
,	O
the	O
symbols	O
"	O
,	O
-	O
,	O
+	O
,	O
*	B-Language
,	O
/	O
,	O
=	O
,	O
,	O
,	O
and	O
the	O
BASIC	B-Language
keyword	O
tokens	O
(	O
with	O
many	O
new	O
added	O
)	O
.	O
</s>
<s>
In	O
the	O
later	O
ZX	B-Operating_System
Spectrum	I-Operating_System
the	O
entire	O
character	B-General_Concept
encoding	I-General_Concept
was	O
replaced	O
with	O
the	O
ZX	B-Operating_System
Spectrum	I-Operating_System
character	B-General_Concept
set	I-General_Concept
,	O
which	O
is	O
a	O
derivative	O
of	O
ASCII	B-Protocol
and	O
includes	O
lower	O
case	O
letters	O
and	O
more	O
.	O
</s>
<s>
The	O
ZX80	B-Operating_System
system	O
font	O
uses	O
an	O
8×8	O
pixel-per-character	O
grid	O
where	O
most	O
glyphs	O
fit	O
in	O
7×6	O
pixels	O
leaving	O
one	O
pixel	O
horizontal	O
space	O
between	O
them	O
.	O
</s>
<s>
This	O
font	O
was	O
modified	O
in	O
the	O
ZX81	O
's	O
ROM	B-Device
to	O
slightly	O
narrower	O
6×6	O
pixel	O
glyphs	O
with	O
two	O
pixels	O
horizontal	O
space	O
between	O
them	O
,	O
which	O
improved	O
the	O
look	O
of	O
single	O
inverted	B-General_Concept
characters	O
by	O
showing	O
inverted	B-General_Concept
pixels	O
on	O
both	O
sides	O
.	O
</s>
<s>
Some	O
glyphs	O
also	O
received	O
a	O
different	O
design	O
in	O
the	O
ZX81	O
system	O
font	O
,	O
noticeable	O
on	O
the	O
*	B-Language
,	O
the	O
slashed	O
and	O
less	O
rounded	O
0	O
,	O
and	O
the	O
less	O
rounded	O
$	O
,	O
C	B-Language
,	O
G	B-Application
and	O
J	B-Language
.	O
</s>
<s>
The	O
following	O
table	O
shows	O
the	O
ZX80	B-Language
character	I-Language
set	I-Language
.	O
</s>
