<s>
The	O
Teletype	B-Application
Model	I-Application
33	I-Application
is	O
an	O
electromechanical	O
teleprinter	O
designed	O
for	O
light-duty	O
office	O
use	O
.	O
</s>
<s>
The	O
Model	O
33	O
was	O
one	O
of	O
the	O
first	O
products	O
to	O
employ	O
the	O
newly-standardized	O
ASCII	B-Protocol
code	I-Protocol
,	O
which	O
was	O
first	O
published	O
in	O
1963	O
.	O
</s>
<s>
Because	O
of	O
its	O
low	O
price	O
and	O
ASCII	B-Protocol
compatibility	O
,	O
the	O
Model	O
33	O
was	O
widely	O
used	O
with	O
early	O
minicomputers	B-Architecture
,	O
and	O
the	O
large	O
numbers	O
of	O
the	O
teleprinter	O
that	O
were	O
sold	O
strongly	O
influenced	O
several	O
de	O
facto	O
standards	O
that	O
developed	O
during	O
the	O
1960s	O
and	O
1970s	O
.	O
</s>
<s>
The	O
Model	O
33	O
originally	O
cost	O
about	O
$1000	O
(	O
equivalent	O
to	O
$	O
today	O
)	O
,	O
much	O
less	O
than	O
other	O
teleprinters	O
and	O
computer	B-General_Concept
terminals	I-General_Concept
in	O
the	O
mid-1960s	O
,	O
such	O
as	O
the	O
Friden	B-Application
Flexowriter	I-Application
and	O
the	O
IBM	B-Device
1050	I-Device
.	O
</s>
<s>
The	O
machines	O
had	O
good	O
durability	O
and	O
faced	O
little	O
competition	O
in	O
their	O
price	O
class	O
,	O
until	O
the	O
appearance	O
of	O
Digital	O
Equipment	O
Corporation	O
's	O
DECwriter	B-Application
series	O
of	O
teleprinters	O
.	O
</s>
<s>
While	O
the	O
manufacturer	O
called	O
the	O
Model	O
33	O
teleprinter	O
with	O
a	O
tape	O
punch	O
and	O
tape	O
reader	O
a	O
"	O
Model	O
33	O
ASR	O
"	O
,	O
many	O
computer	O
users	O
used	O
the	O
shorter	O
term	O
"	O
ASR-33	B-Application
"	O
.	O
</s>
<s>
The	O
earliest	O
known	O
source	O
for	O
this	O
equipment	O
naming	O
discrepancy	O
comes	O
from	O
Digital	O
Equipment	O
Corporation	O
(	O
DEC	O
)	O
documentation	O
,	O
where	O
the	O
September	O
1963	O
PDP-4	O
Brochure	O
calls	O
the	O
Teletype	B-Application
Model	I-Application
28	I-Application
KSR	O
a	O
"	O
KSR-28	O
"	O
in	O
the	O
paragraph	O
titled	O
"	O
Printer-Keyboard	O
and	O
Control	O
Type	O
65	O
"	O
.	O
</s>
<s>
This	O
naming	O
convention	O
was	O
extended	O
from	O
the	O
Teletype	B-Application
Model	I-Application
28	I-Application
to	O
other	O
Teletype	O
equipment	O
in	O
later	O
DEC	O
documentation	O
,	O
consistent	O
with	O
DEC	O
's	O
practice	O
of	O
designating	O
equipment	O
using	O
letters	O
followed	O
by	O
numerals	O
.	O
</s>
<s>
For	O
example	O
,	O
the	O
DEC	O
PDP-15	B-Device
price	O
list	O
from	O
April	O
1970	O
lists	O
a	O
number	O
of	O
Teletype	O
Corporation	O
teletypewriters	O
using	O
this	O
alternative	O
naming	O
convention	O
.	O
</s>
<s>
For	O
example	O
,	O
Micro	O
Instrumentation	O
and	O
Telemetry	O
Systems	O
marketed	O
the	O
Teletype	B-Application
Model	I-Application
33	I-Application
ASR	O
as	O
"	O
Teletype	B-Application
ASR-33	I-Application
"	O
.	O
</s>
<s>
The	O
trigram	B-General_Concept
""	O
became	O
widely	O
used	O
as	O
an	O
informal	O
abbreviation	O
for	O
"	O
Teletype	O
"	O
,	O
often	O
used	O
to	O
designate	O
the	O
main	O
text	O
input	O
and	O
output	O
device	O
on	O
many	O
early	O
computer	O
systems	O
.	O
</s>
<s>
Early	O
video	B-General_Concept
terminals	I-General_Concept
,	O
such	O
as	O
the	O
Tektronix	B-General_Concept
4010	I-General_Concept
,	O
did	O
not	O
become	O
available	O
until	O
1970	O
,	O
and	O
initially	O
cost	O
around	O
$	O
10,000	O
(	O
equivalent	O
to	O
$	O
today	O
)	O
.	O
</s>
<s>
However	O
,	O
the	O
introduction	O
of	O
integrated	O
circuits	O
and	O
semiconductor	O
memory	O
later	O
that	O
decade	O
allowed	O
the	O
price	O
of	O
cathode-ray-tube-based	O
terminals	O
to	O
rapidly	O
fall	O
below	O
the	O
price	O
of	O
a	O
Teletype	O
teleprinter	O
.	O
</s>
<s>
"	O
Dumb	O
terminals	O
"	O
,	O
such	O
as	O
the	O
low-cost	O
ADM-3A	B-Device
(	O
1976	O
)	O
began	O
to	O
undercut	O
the	O
market	O
for	O
Teletype	O
terminals	O
.	O
</s>
<s>
Such	O
basic	O
video	B-General_Concept
terminals	I-General_Concept
,	O
which	O
could	O
only	O
sequentially	O
display	O
lines	O
of	O
text	O
and	O
scroll	O
them	O
,	O
were	O
often	O
called	O
glass	B-General_Concept
teletypes	I-General_Concept
(	O
"	O
glass	O
TTYs	O
"	O
)	O
analogous	O
to	O
the	O
Teletype	O
printers	O
.	O
</s>
<s>
More-advanced	O
video	B-General_Concept
terminals	I-General_Concept
,	O
such	O
as	O
the	O
Digital	O
Equipment	O
Corporation	O
VT100	B-Device
(	O
1978	O
)	O
,	O
could	O
communicate	O
much	O
faster	O
than	O
electromechanical	O
printers	O
,	O
and	O
could	O
support	O
use	O
of	O
a	O
full-screen	O
text	B-Application
editor	I-Application
program	O
without	O
generating	O
large	O
amounts	O
of	O
paper	O
printouts	O
.	O
</s>
<s>
Teletype	O
machines	O
were	O
gradually	O
replaced	O
in	O
new	O
installations	O
by	O
much	O
faster	O
dot-matrix	O
printers	O
and	O
video	B-General_Concept
terminals	I-General_Concept
in	O
the	O
middle-to-late	O
1970s	O
.	O
</s>
<s>
Similar	O
noises	O
became	O
iconic	O
for	O
the	O
sounds	O
of	O
an	O
active	O
newswire	O
or	O
computer	B-General_Concept
terminal	I-General_Concept
.	O
</s>
<s>
The	O
Teletype	B-Application
Model	I-Application
33	I-Application
,	O
including	O
the	O
stand	O
,	O
stood	O
high	O
,	O
wide	O
and	O
deep	O
,	O
not	O
including	O
the	O
paper	O
holder	O
.	O
</s>
<s>
Configuration	O
of	O
user-selectable	O
options	O
(	O
such	O
as	O
parity	B-Error_Name
)	O
was	O
done	O
with	O
mechanical	O
clips	O
that	O
depressed	O
or	O
released	O
various	O
levers	O
.	O
</s>
<s>
Earlier	O
Teletype	O
machine	O
designs	O
,	O
such	O
as	O
the	O
Model	B-Application
28	I-Application
ASR	O
,	O
had	O
allowed	O
the	O
user	O
to	O
operate	O
the	O
keyboard	O
to	O
punch	O
tape	O
while	O
independently	O
transmitting	O
a	O
previously	O
punched	O
tape	O
,	O
or	O
to	O
punch	O
a	O
tape	O
while	O
printing	O
something	O
else	O
.	O
</s>
<s>
The	O
Model	O
33	O
keyboard	O
generated	O
the	O
seven-bit	B-Protocol
ASCII	I-Protocol
code	O
,	O
also	O
known	O
as	O
CCITT	O
International	O
Telegraphic	O
Alphabet	O
No	O
.	O
</s>
<s>
5	O
,	O
with	O
one	O
(	O
even	O
)	O
parity	B-Error_Name
bit	I-Error_Name
and	O
two	O
stop	O
bits	O
,	O
with	O
a	O
symbol	O
rate	O
of	O
110	O
baud	O
,	O
but	O
it	O
only	O
supported	O
an	O
upper-case	O
subset	O
of	O
that	O
code	O
;	O
it	O
did	O
not	O
support	O
lower-case	O
letters	O
or	O
the	O
,	O
,	O
,	O
,	O
and	O
characters	O
.	O
</s>
<s>
The	O
Model	O
33	O
could	O
operate	O
either	O
in	O
half-duplex	O
mode	O
,	O
in	O
which	O
signals	O
from	O
the	O
keyboard	O
were	O
sent	O
to	O
the	O
print	O
mechanism	O
,	O
so	O
that	O
characters	O
were	O
printed	O
as	O
they	O
were	O
typed	O
(	O
local	B-Error_Name
echo	I-Error_Name
)	O
,	O
or	O
in	O
full-duplex	O
mode	O
,	O
in	O
which	O
keyboard	O
signals	O
are	O
sent	O
only	O
to	O
the	O
transmission	O
line	O
,	O
and	O
the	O
receiver	O
would	O
have	O
to	O
transmit	O
the	O
character	O
back	O
to	O
the	O
Model	O
33	O
in	O
order	O
for	O
it	O
to	O
be	O
printed	O
(	O
remote	B-Error_Name
echo	I-Error_Name
)	O
.	O
</s>
<s>
The	O
Teletype	B-Application
Model	I-Application
33	I-Application
contained	O
an	O
answer-back	O
mechanism	O
that	O
was	O
generally	O
used	O
in	O
dial-up	O
networks	O
such	O
as	O
the	O
TWX	O
network	O
.	O
</s>
<s>
An	O
acoustic	B-Device
coupler	I-Device
for	O
a	O
de	O
facto	O
standard	O
sized	O
and	O
shaped	O
telephone	O
handset	O
was	O
also	O
available	O
.	O
</s>
<s>
Another	O
CCU	O
type	O
was	O
called	O
"	O
Computer	O
Control	O
Private	O
Line	O
"	O
,	O
which	O
operated	O
on	O
a	O
local	O
20	O
mA	O
current	O
loop	O
,	O
the	O
de	O
facto	O
standard	O
serial	O
protocol	O
for	O
computer	B-General_Concept
terminals	I-General_Concept
before	O
the	O
rise	O
of	O
RS-232	O
signaling	O
.	O
</s>
<s>
Teletype	O
also	O
introduced	O
a	O
more-expensive	O
ASCII	B-Protocol
Model	O
35	O
(	O
ASR-35	O
)	O
for	O
heavy-duty	O
use	O
,	O
whose	O
printer	O
mechanism	O
was	O
based	O
on	O
the	O
older	O
,	O
rugged	O
Model	B-Application
28	I-Application
.	O
</s>
<s>
The	O
Model	O
35	O
was	O
widely	O
used	O
as	O
terminals	O
for	O
the	O
minicomputers	B-Architecture
and	O
IMPs	O
to	O
send	O
and	O
receive	O
text	O
messages	O
over	O
the	O
very	O
early	O
ARPANET	O
,	O
which	O
later	O
evolved	O
into	O
the	O
Internet	O
.	O
</s>
<s>
A	O
two-color	O
inked	O
ribbon	O
and	O
additional	O
ASCII	B-Protocol
control	O
codes	O
allowed	O
automatic	O
switching	O
between	O
red	O
and	O
black	O
output	O
while	O
printing	O
.	O
</s>
<s>
A	O
wider	O
pin-feed	O
platen	O
and	O
typing	O
mechanism	O
allowed	O
printing	O
132	O
columns	O
on	O
fan-fold	O
paper	O
,	O
making	O
its	O
output	O
similar	O
to	O
the	O
132-column	O
page	O
size	O
of	O
the	O
then	O
industry-standard	O
IBM	B-Device
1403	I-Device
model	O
printers	O
.	O
</s>
<s>
ASCII	B-Protocol
was	O
first	O
used	O
commercially	O
during	O
1963	O
as	O
a	O
seven-bit	O
teleprinter	O
code	O
for	O
American	O
Telephone	O
&	O
Telegraph	O
's	O
Teletypewriter	O
eXchange	O
TWX	O
network	O
using	O
Teletype	B-Application
Model	I-Application
33	I-Application
teleprinters	O
.	O
</s>
<s>
The	O
upper-case-only	O
limitation	O
of	O
the	O
widely-used	O
Teletype	B-Application
Model	I-Application
33	I-Application
constrained	O
many	O
early	O
computer	O
languages	O
and	O
systems	O
to	O
communicate	O
in	O
ALL	O
CAPS	O
,	O
establishing	O
an	O
association	O
of	O
this	O
text	O
stylization	O
with	O
early	O
computing	O
technology	O
in	O
general	O
.	O
</s>
<s>
The	O
Teletype	B-Application
Model	I-Application
33	I-Application
series	O
was	O
influential	O
in	O
the	O
development	O
and	O
interpretation	O
of	O
ASCII	B-Protocol
code	I-Protocol
characters	O
.	O
</s>
<s>
In	O
particular	O
,	O
the	O
Teletype	B-Application
Model	I-Application
33	I-Application
machine	O
assignments	O
for	O
codes	O
17	O
(	O
Control-Q	O
,	O
DC1	O
,	O
also	O
known	O
as	O
XON	O
)	O
and	O
19	O
(	O
Control-S	O
,	O
DC3	O
,	O
also	O
known	O
as	O
XOFF	O
)	O
became	O
de	O
facto	O
standards	O
.	O
</s>
<s>
The	O
programming	O
language	O
BASIC	O
was	O
designed	O
to	O
be	O
written	O
and	O
edited	O
on	O
a	O
low-speed	O
Teletype	B-Application
Model	I-Application
33	I-Application
.	O
</s>
<s>
The	O
slow	O
speed	O
of	O
the	O
Teletype	B-Application
Model	I-Application
33	I-Application
influenced	O
the	O
user	O
interface	O
of	O
minicomputer	B-Architecture
operating	O
systems	O
,	O
including	O
UNIX	B-Application
.	O
</s>
<s>
A	O
Teletype	B-Application
Model	I-Application
33	I-Application
provided	O
Bill	O
Gates	O
 '	O
first	O
computing	O
experience	O
.	O
</s>
<s>
In	O
1965	O
,	O
Stanford	O
University	O
psychology	O
professors	O
Patrick	O
Suppes	O
and	O
Richard	O
C	O
.	O
Atkinson	O
,	O
in	O
the	O
pilot	O
program	O
for	O
computer	O
assisted	O
instruction	O
,	O
experimented	O
with	O
using	O
computers	O
to	O
provide	O
arithmetic	O
and	O
spelling	O
drills	O
via	O
Teletypes	O
and	O
acoustic	B-Device
couplers	I-Device
to	O
elementary	O
school	O
students	O
in	O
the	O
Palo	O
Alto	O
Unified	O
School	O
District	O
in	O
California	O
and	O
elsewhere	O
.	O
</s>
<s>
In	O
1971	O
,	O
Ray	O
Tomlinson	O
chose	O
the	O
"	O
@	O
"	O
symbol	O
on	O
his	O
Teletype	B-Application
Model	I-Application
33	I-Application
ASR	O
keyboard	O
for	O
use	O
in	O
network	O
email	O
addresses	O
.	O
</s>
<s>
The	O
serial	O
ports	O
in	O
Unix	B-Application
and	O
Linux	B-Application
are	O
named	O
,	O
which	O
is	O
short	O
for	O
"	O
Teletype	O
"	O
.	O
</s>
