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Operating instructions

ManualsBrandsDigiPos ManualsComputer equipmentDS-810
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Theory
of
Operation-71380
Symbol
Description
A
small
circle
at
the
input
or
output
of
a
symbol
indicates
that
the
LO
state
is
the
significant
state
.
Absence
of
the
circle
indicates
that
the
HI
state
is
the
significant
state
.
Two
examples
follow
:
AND
gate
with
LO-state
indicator
at
the
A
input
.
The
output
of
this
gate
is
HI
if
and
only
if
the
A
input
is
LO
and
the
B
input
is
HI
.
OR
gate
with LO-state
indicator
at
the
A
input
:
The
output of
this
gate
is
HI
if
either
the
A
input
is
LO
or
the
B
input
is
H
I .
Indicates
that
this
input
(usually
the
trigger
input
of
a
flip-top)
re-
sponds
to
the
indicated
transition
of
the
applied
signal
.
A
bistable
device
with
one
input
and
two
outputs
(either
or
both
outputs
may
be
used)
.
When
trig-
gered,
the
outputs
change
from
one
stable
state
to
the
other
stable
state
with each
trigger
.
The
outputs
are
complementary
(i
.e
.,
when
one
out-
put
is
HI
the
other
is
LO)
.
The
dynamic
indicator
on the
trigger
(T)
input
may
be
of
either
polarity
depending
on
the
device
.
Device
LO-state
indicator
Dynamic
Indicator
Triggered
(toggle)
Flip-Flop
a
X
TABLE
3-
1
(cont)
Input/Output Table
Input
/Output
Input
/
Output
A
B X
LO
LO LO
LO
HI HI
H
I
LO LO
HI
J
HI
LO
Condition Condition
before
after
trigger trigger
pulse pulse
Q
Q Q Q
LO
HI
HI
LO
HI
LO LO
HI
1