Theory
Of
Operation-7M13
displayed
on
1IIe
CRT.
O
n
l
y when
a
wri18
command signal is present (output
of U202A) can
U200
read
the
address present at the
o
u
tp
u
t
of U198.
When
1IIe
address-to-memory command signal is presented
to
the
memories, information present on the
data
inputs
to
the m
em
o
ri
es
will be accepted for storage. Once this is
accomplished,
U200 returns
to
read
i
n
g
1IIe
addresses
from
U195
(time slot information) and the newly
stored character is displayed on
the CRT.
The MODIFY
p
u
sh
b
utt
o
n
permits
in18rruption
of
the
address
advance
pulse
(
o
u
tpu
t
of
U132C).
When
pressed and
h
e
l
d
,
the
MODIFY
pushbutton
allows
1IIe
la
s
t
entered
character to
be
changed
r
ega
rd
l
ess
of
its
posi
t
i
o
n
in the display.
The
SPACE
p
ush
b
u
tt
o
n
ge
n
e
r
a
tes
o
n
l
y
row
data, therefore, CR102 is
used
to
allow generation
of
the
wri
t
e-
i
n
to
-
m
e
m
o
ry and
associated
s
ig
na
l
s
through the output
of
Ul68B. This
allows
d
a
t
a
for
s
pa
c
e
generation
to be
stored
in the memories and displayed in the same
manner
as
a
cha
r
acte
r
.
The
camera
counter
works only
th
r
o
u
g
h
the
lower,
c
h
a
n
n
e
l
2, display
position.
When the
camera
c
o
u
n
te
r
is selected,
it causes
ti
m
e
slots
9
and
10
to
be reserved
for
the camera counter display. This is
acc
o
mp
l
i
s
h
ed
by
the
o
u
tp
u
t
of U166A which blocks
the
memories
during these time
s
lo
t
s
to
allow camera
co
u
n
te
r
information
f
r
o
m
U159
(units
digiti
and
U1
6
1
(tens d
i
g
i
t
i
to
be
d
i
sp
l
a
y
ed.
Pressing (P)RESET
clears
U129A,
b
l
ock
s U166D and resets
Ul54
and
U157
t
o
zero. The output
of
U105E
activates
the current necessary
for
zero character generation when
no
d
ata
is
p
r
e
sent at the outputs
of
U159
a
n
d
U161. Pressing a number pushbutton (while p
r
e
s
s
i
n
g
and holding
the
(P)RESET
pushbutton)
enters that number in
the tens p
osi
t
i
o
n
, U 157,
which
is
enabled
b
y
U132B.
The
ac
t
i
o
n
of
U 122,
w
h
e
n
ttle
n
u
mbe
r
pushbutton is pressed,
causes
Ul29A
to
switch.
T
h
i
s
allows
1IIe
next
n
u
m
be
r
to
be
entered
as
a
units
digit in U154-now enabled b
y
U132A.
Camera
coun1Br
data is presented to the
i
n
p
u
ts
of
U265
during
ti
m
e
slots
9
and
10. U161
is
activated by
U163C
d
u
ri
n
g
time
siot
9.
U
15
9
is
a
ctiv
a
ted
during time
slot
10 by U163B.
The
ADVANCE
pushbutton, when pressed,
provides
a ground
closure for
advancing the camera c
ou
n
t
.
The SYNC IN
jack
provides the same
fu
n
c
t
i
o
n
when
connected to a
c
a
m
er
a
shutter.
The
o
u
tpu
t
of
U202A
provides an over-ride of
the
blo
c
k
i
n
g
action of
U
1
66
A
d
u
r
i
n
g
time slots 9
a
n
d
10
when the
camera counter is
selected.
This
permits
e
n
try
of other
i
n
f
o
r
m
a
t
i
o
n
during
these time slots. The
camera
counter
d
i
s
p
l
a
y
is
n
o
t
erased
by
the
ERASE
pushbutton.
The outputs of
U225, U245, U265, and U285
determine
which
characters
a
r
e
generated
in
the
readout
system. Refer
t
o
the schematic
d
i
a
g
ra
m
for
the
fu
n
ct
i
o
n
a
l
identification
of
these
IC's.
These
IC's
convert
the
BCD
input
to an
output
c
u
r
rent
.
This is accomplished by
using
the
BCD
inputs
to
select
current
inputs
to pins
10, 11, 12,
13,
and
14
which
are
used
either
singly
or
combined
to produce
the
proper
current
outputs (row
a
n
d
column
)
for
character
generation in
the
re
ad
o
u
t
system.
2-2