<s>
The	O
3P+S	B-Architecture
Input/Output	O
Module	O
was	O
an	O
S-100	B-Architecture
expansion	I-Architecture
card	I-Architecture
introduced	O
to	O
the	O
microcomputer	B-Architecture
market	O
by	O
Processor	O
Technology	O
.	O
</s>
<s>
It	O
supplied	O
three	O
parallel	B-Device
ports	I-Device
and	O
one	O
serial	B-Protocol
port	I-Protocol
,	O
the	O
latter	O
of	O
which	O
conformed	O
to	O
the	O
RS-232C	O
standard	O
.	O
</s>
<s>
One	O
of	O
the	O
three	O
parallel	B-Device
ports	I-Device
was	O
dedicated	O
to	O
interfacing	O
with	O
the	O
host	O
computer	O
over	O
the	O
S-100	B-Architecture
bus	I-Architecture
,	O
while	O
the	O
other	O
two	O
were	O
available	O
for	O
general	O
use	O
.	O
</s>
<s>
An	O
Altair	B-Architecture
8800	I-Architecture
equipped	O
with	O
a	O
3P+S	B-Architecture
could	O
use	O
one	O
of	O
the	O
parallel	B-Device
ports	I-Device
to	O
accept	O
input	O
from	O
a	O
keyboard	B-Device
and	O
another	O
to	O
output	O
to	O
a	O
TV	B-Device
Typewriter	I-Device
,	O
allowing	O
the	O
user	O
to	O
construct	O
an	O
all-in-one	O
machine	O
that	O
did	O
not	O
need	O
an	O
external	O
computer	B-General_Concept
terminal	I-General_Concept
to	O
work	O
.	O
</s>
<s>
This	O
also	O
left	O
the	O
serial	B-Protocol
port	I-Protocol
free	O
,	O
which	O
could	O
be	O
used	O
to	O
drive	O
a	O
teletype	O
machine	O
as	O
a	O
computer	O
printer	O
,	O
or	O
a	O
punch	O
tape	O
system	O
for	O
storage	O
.	O
</s>
<s>
Processor	O
Technology	O
later	O
combined	O
the	O
3P+S	B-Architecture
with	O
the	O
VDM-1	B-Device
graphics	B-Device
card	I-Device
in	O
a	O
compact	O
S-100	O
machine	O
of	O
their	O
own	O
to	O
produce	O
the	O
Sol-20	B-Architecture
,	O
the	O
first	O
all-in-one	O
mass-produced	O
personal	B-Device
computer	I-Device
.	O
</s>
