<s>
The	O
IBM	B-Device
557	I-Device
Alphabetic	O
Interpreter	O
allowed	O
holes	O
in	O
punched	B-Architecture
cards	I-Architecture
to	O
be	O
interpreted	O
and	O
the	O
punched	B-Architecture
card	I-Architecture
characters	O
printed	O
on	O
any	O
row	O
or	O
column	O
,	O
selected	O
by	O
a	O
control	O
panel	O
.	O
</s>
<s>
Introduced	O
in	O
1954	O
,	O
the	O
machine	O
was	O
a	O
synchronous	O
system	O
where	O
brushes	O
would	O
glide	O
over	O
a	O
hole	O
in	O
a	O
punched	B-Architecture
card	I-Architecture
and	O
contact	O
a	O
brass	O
roller	O
thereby	O
setting	O
up	O
part	O
of	O
a	O
character	O
code	O
.	O
</s>
<s>
The	O
punched	B-Architecture
card	I-Architecture
was	O
fed	O
from	O
the	O
card	O
hopper	O
and	O
read	O
by	O
means	O
of	O
an	O
electrical	O
voltage	O
placed	O
onto	O
a	O
metal	O
‘	O
Contact	O
Roll’	O
,	O
timing	O
controlled	O
by	O
a	O
‘	O
Master	O
Circuit	O
Breaker	O
,	O
and	O
80	O
‘	O
Read	O
Brushes’	O
,	O
one	O
brush	O
for	O
each	O
card	O
column	O
,	O
and	O
‘	O
Wire	O
Contact	O
Relays’	O
which	O
decoded	O
the	O
data	O
.	O
</s>
<s>
The	O
punched	B-Architecture
card	I-Architecture
acted	O
as	O
an	O
insulator	O
and	O
an	O
electrical	O
contact	O
was	O
only	O
completed	O
in	O
the	O
presence	O
of	O
a	O
punched	O
hole	O
.	O
</s>
<s>
The	O
lifter	O
bars	O
were	O
then	O
lowered	O
under	O
spring	O
tension	O
by	O
the	O
‘	O
mechanical	O
bail’	O
in	O
time	O
with	O
the	O
reading	O
of	O
the	O
punched	B-Architecture
card	I-Architecture
.	O
</s>
<s>
A	O
‘	O
card	O
shield’	O
would	O
grab	O
the	O
punched	B-Architecture
card	I-Architecture
to	O
hold	O
it	O
in	O
place	O
and	O
lower	O
it	O
a	O
position	O
almost	O
touching	O
the	O
inked	O
print	O
ribbon	O
and	O
print	O
wheel	O
.	O
</s>
<s>
At	O
the	O
correct	O
time	O
60	O
‘	O
hammers’	O
,	O
under	O
spring	O
tension	O
and	O
controlled	O
by	O
a	O
cam	O
,	O
would	O
‘	O
fire’	O
pressing	O
the	O
card	O
/	O
inked	O
ribbon	O
onto	O
the	O
print	O
wheel	O
and	O
leaving	O
an	O
inked	O
impression	O
of	O
the	O
character	O
on	O
the	O
surface	O
of	O
the	O
punched	B-Architecture
card	I-Architecture
.	O
</s>
