<s>
The	O
DECwriter	B-Application
series	O
was	O
a	O
family	O
of	O
computer	B-General_Concept
terminals	I-General_Concept
from	O
Digital	O
Equipment	O
Corporation	O
(	O
DEC	O
)	O
.	O
</s>
<s>
In	O
contrast	O
to	O
teletypes	O
,	O
the	O
DECwriters	B-Application
were	O
based	O
on	O
dot	O
matrix	O
printer	O
technology	O
,	O
one	O
of	O
the	O
first	O
examples	O
of	O
such	O
a	O
system	O
to	O
be	O
introduced	O
.	O
</s>
<s>
Versions	O
lacking	O
a	O
keyboard	O
were	O
also	O
available	O
for	O
use	O
as	O
computer	O
printers	O
,	O
which	O
eventually	O
became	O
the	O
only	O
models	O
as	O
smart	O
terminals	O
became	O
the	O
main	O
way	O
to	O
interact	O
with	O
mainframes	B-Architecture
and	O
minicomputers	B-Architecture
in	O
the	O
1980s	O
.	O
</s>
<s>
There	O
were	O
four	O
series	O
of	O
machines	O
,	O
starting	O
with	O
the	O
original	O
DECwriter	B-Application
in	O
1970	O
,	O
the	O
DECwriter	B-Application
II	O
in	O
1974	O
,	O
DECwriter	B-Application
III	O
in	O
1978	O
,	O
and	O
the	O
final	O
DECwriter	B-Application
IV	O
in	O
1982	O
.	O
</s>
<s>
They	O
differed	O
primarily	O
in	O
speed	O
and	O
the	O
selection	O
of	O
computer	B-Application
interfaces	I-Application
.	O
</s>
<s>
The	O
DECwriters	B-Application
were	O
among	O
DEC	O
's	O
best-selling	O
products	O
,	O
notably	O
the	O
II	O
and	O
III	O
series	O
.	O
</s>
<s>
The	O
original	O
DECwriter	B-Application
was	O
introduced	O
in	O
November	O
1970	O
at	O
the	O
Fall	O
Joint	O
Computer	O
Conference	O
.	O
</s>
<s>
At	O
the	O
time	O
,	O
most	O
small	O
computer	O
systems	O
were	O
accessed	O
using	O
surplus	O
or	O
new	O
teletype	O
units	O
,	O
such	O
as	O
the	O
popular	O
ASR-33	B-Application
.	O
</s>
<s>
As	O
such	O
,	O
its	O
only	O
computer	B-Application
interface	I-Application
was	O
a	O
30mA	O
current	O
loop	O
,	O
as	O
used	O
on	O
teletype	O
machines	O
,	O
with	O
the	O
explicit	O
goal	O
of	O
"	O
having	O
been	O
designed	O
to	O
replace	O
the	O
standard	O
Teletype	B-Application
Model	I-Application
33	I-Application
,	O
35	O
and	O
37	O
KSR	O
"	O
.	O
</s>
<s>
The	O
LA30	O
used	O
a	O
64-character	O
ASCII-based	O
character	B-General_Concept
set	I-General_Concept
,	O
lacking	O
lower-case	O
characters	O
and	O
printing	O
them	O
in	O
upper-case	O
.	O
</s>
<s>
It	O
used	O
a	O
7-pin	O
print	O
head	O
with	O
glyphs	B-Application
in	O
a	O
5x7	O
grid	O
.	O
</s>
<s>
However	O
,	O
carriage	O
returns	O
required	O
of	O
a	O
second	O
,	O
during	O
which	O
time	O
the	O
host	O
computer	O
had	O
to	O
send	O
data	O
it	O
would	O
know	O
would	O
not	O
be	O
printed	O
,	O
the	O
so-called	O
"	O
fill	B-General_Concept
characters	I-General_Concept
"	O
that	O
were	O
commonly	O
required	O
by	O
printers	O
of	O
the	O
era	O
.	O
</s>
<s>
The	O
casing	O
around	O
the	O
keyboard	O
was	O
curved	O
,	O
somewhat	O
similar	O
to	O
the	O
ADM-3A	B-Device
.	O
</s>
<s>
In	O
June	O
1972	O
,	O
DEC	O
introduced	O
two	O
new	O
versions	O
of	O
the	O
DECwriter	B-Application
,	O
the	O
LA30A	O
which	O
lacked	O
a	O
keyboard	O
and	O
was	O
used	O
as	O
a	O
dedicated	O
printer	O
,	O
and	O
the	O
LA30-E	O
which	O
added	O
an	O
RS-232	O
interface	O
option	O
,	O
the	O
"	O
E	O
"	O
standing	O
for	O
the	O
new	O
name	O
for	O
the	O
port	O
,	O
EIA-232	O
.	O
</s>
<s>
A	O
later	O
addition	O
was	O
the	O
LA30-P	O
,	O
the	O
"	O
P	O
"	O
referring	O
to	O
the	O
addition	O
of	O
a	O
parallel	O
Centronics	B-Device
port	I-Device
,	O
which	O
had	O
become	O
an	O
almost	O
universal	O
de	O
facto	O
standard	O
by	O
the	O
mid-1970s	O
.	O
</s>
<s>
A	O
replacement	O
for	O
the	O
original	O
product	O
line	O
was	O
announced	O
in	O
August	O
1974	O
with	O
the	O
introduction	O
of	O
the	O
DECwriter	B-Application
II	O
series	O
and	O
its	O
first	O
model	O
,	O
the	O
LA36	O
.	O
</s>
<s>
The	O
primary	O
change	O
was	O
the	O
addition	O
of	O
a	O
data	B-General_Concept
buffer	I-General_Concept
that	O
allowed	O
it	O
to	O
store	O
characters	O
.	O
</s>
<s>
When	O
the	O
print	O
head	O
fell	O
behind	O
,	O
it	O
began	O
printing	O
characters	O
as	O
fast	O
as	O
possible	O
until	O
the	O
buffer	B-General_Concept
was	O
empty	O
again	O
,	O
at	O
speeds	O
as	O
high	O
as	O
60cps	O
.	O
</s>
<s>
This	O
had	O
the	O
added	O
advantage	O
that	O
the	O
host	O
computer	O
did	O
not	O
have	O
to	O
insert	O
fill	B-General_Concept
characters	I-General_Concept
,	O
which	O
in	O
turn	O
led	O
to	O
simpler	O
interfacing	O
requirements	O
and	O
reduced	O
device	B-Application
driver	I-Application
complexity	O
.	O
</s>
<s>
The	O
character	B-General_Concept
set	I-General_Concept
now	O
included	O
a	O
complete	O
128-character	O
ASCII	B-Protocol
set	O
,	O
including	O
upper	O
and	O
lower	O
case	O
as	O
well	O
as	O
various	O
control	O
characters	O
.	O
</s>
<s>
The	O
character	B-General_Concept
set	I-General_Concept
was	O
stored	O
in	O
read	B-Device
only	I-Device
memory	I-Device
(	O
ROM	B-Device
)	O
,	O
and	O
optional	O
ROMs	O
for	O
Katakana	O
and	O
the	O
APL	B-Language
symbols	O
were	O
also	O
available	O
.	O
</s>
<s>
The	O
Intertec	O
Superdec	O
offered	O
1200bit/s	O
support	O
,	O
double-wide	O
characters	O
,	O
APL	B-Language
characters	O
,	O
and	O
even	O
user-defined	O
character	B-General_Concept
sets	I-General_Concept
.	O
</s>
<s>
The	O
Datasouth	O
DS120	O
was	O
similar	O
,	O
lacking	O
the	O
character	B-General_Concept
sets	I-General_Concept
but	O
adding	O
bidirectional	O
printing	O
.	O
</s>
<s>
The	O
Selanar	O
Graphics	O
II	O
add-on	O
offered	O
bitmapped	B-Algorithm
graphics	I-Algorithm
support	O
as	O
well	O
as	O
increased	O
speeds	O
to	O
9,600	O
bit/s	O
.	O
</s>
<s>
This	O
was	O
essentially	O
a	O
simplified	O
version	O
of	O
the	O
LA35	O
,	O
offered	O
only	O
with	O
a	O
Centronics	B-Device
port	I-Device
to	O
provide	O
speeds	O
up	O
to	O
180cps	O
.	O
</s>
<s>
January	O
1977	O
saw	O
the	O
introduction	O
of	O
the	O
DECwriter	B-Application
III	O
,	O
or	O
LS120	O
.	O
</s>
<s>
Internally	O
,	O
the	O
primary	O
change	O
was	O
the	O
addition	O
of	O
a	O
1kB	O
character	O
buffer	B-General_Concept
,	O
which	O
allowed	O
it	O
to	O
store	O
many	O
lines	O
of	O
text	O
.	O
</s>
<s>
The	O
printer	O
electronics	O
examined	O
the	O
data	O
,	O
skipping	O
over	O
blank	O
areas	O
at	O
high	O
speed	O
,	O
and	O
optimizing	O
printing	O
in	O
both	O
directions	O
by	O
reading	O
backward	O
through	O
the	O
buffer	B-General_Concept
where	O
appropriate	O
.	O
</s>
<s>
In	O
addition	O
to	O
the	O
character	B-General_Concept
sets	I-General_Concept
of	O
the	O
II	O
series	O
,	O
the	O
III	O
added	O
new	O
character	B-General_Concept
sets	I-General_Concept
with	O
National	O
Replacement	O
Character	B-General_Concept
Sets	I-General_Concept
for	O
Finland	O
,	O
Denmark	O
,	O
Sweden	O
,	O
Germany	O
,	O
Norway	O
,	O
and	O
France	O
.	O
</s>
<s>
The	O
LA120s	O
normally	O
were	O
supplied	O
with	O
only	O
an	O
RS-232	O
interface	O
,	O
but	O
the	O
LA12X-AL	O
add-on	O
kit	O
provided	O
a	O
current	O
loop	O
interface	O
for	O
those	O
who	O
still	O
needed	O
it	O
,	O
while	O
the	O
LA12X-BB	O
added	O
parallel	O
interface	O
,	O
and	O
the	O
LA12X-CB	O
connected	O
to	O
the	O
Unibus	B-Device
.	O
</s>
<s>
The	O
LA12X-DL	O
option	O
expanded	O
the	O
character	O
buffer	B-General_Concept
to	O
4kB	O
.	O
</s>
<s>
The	O
first	O
complete	O
redesign	O
of	O
the	O
DECwriter	B-Application
line	O
was	O
introduced	O
in	O
June	O
1982	O
with	O
the	O
DECwriter	B-Application
IV	O
.	O
</s>
<s>
They	O
were	O
slow	O
,	O
at	O
30cps	O
,	O
and	O
were	O
not	O
intended	O
as	O
outright	O
replacements	O
for	O
the	O
III	O
series	O
,	O
which	O
were	O
more	O
suited	O
to	O
unattended	O
computer-room	O
console	B-General_Concept
terminal	I-General_Concept
operation	O
.	O
</s>
<s>
The	O
DECwriter	B-Application
IV	O
series	O
also	O
introduced	O
optional	O
support	O
for	O
DEC	O
's	O
sixel	O
graphics	O
format	O
,	O
allowing	O
it	O
to	O
produce	O
black	O
and	O
white	O
graphics	O
output	O
.	O
</s>
<s>
This	O
worked	O
by	O
sending	O
characters	O
using	O
only	O
6	O
of	O
the	O
8	O
bits	O
of	O
the	O
printable	O
character	B-General_Concept
set	I-General_Concept
and	O
using	O
those	O
six	O
bits	O
to	O
directly	O
control	O
six	O
of	O
the	O
seven	O
pins	O
in	O
the	O
print	O
head	O
.	O
</s>
<s>
The	O
internal	O
character	B-General_Concept
set	I-General_Concept
ROM	B-Device
was	O
further	O
expanded	O
to	O
support	O
the	O
British	O
,	O
Finnish	O
,	O
French	O
,	O
Canadian	O
French	O
,	O
German	O
,	O
Italian	O
,	O
Norwegian/Danish	O
,	O
Spanish	O
,	O
and	O
Swedish	O
character	B-General_Concept
sets	I-General_Concept
.	O
</s>
<s>
More	O
interesting	O
was	O
the	O
addition	O
of	O
plug-in	O
ROM	B-Protocol
cartridges	I-Protocol
containing	O
the	O
actual	O
glyph	B-Application
data	O
for	O
the	O
characters	O
.	O
</s>
<s>
The	O
system	O
could	O
support	O
two	O
plug-in	B-Protocol
cartridges	I-Protocol
and	O
as	O
many	O
as	O
three	O
internal	O
ROMs	O
(	O
bare	O
chips	O
)	O
,	O
to	O
allow	O
up	O
to	O
five	O
character	B-General_Concept
sets	I-General_Concept
at	O
a	O
time	O
.	O
</s>
<s>
The	O
LA12	O
DECwriter	B-Application
Correspondent	O
was	O
a	O
small	O
form-factor	O
terminal	O
for	O
portable	O
use	O
,	O
weighing	O
.	O
</s>
<s>
Various	O
models	O
offered	O
built-in	O
modems	B-Application
or	O
other	O
interfaces	B-Application
.	O
</s>
