IBM 80 - Page 60

60 S P E C I A L D E V ICE S
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On a Type 75 or 80 machine, the control panel,
the brush selection switches, and the operational control
switches are all mounted on a special inclined cover
plate on the right end of the machine.
Operation of all multiple column selection external
controls, including the layout and wiring of the con-
trol panel,
is similar for the Type 75, 80 and 82
machines.
Control Panel
A diagram of the control panel is shown in Figure
44. The brush positions, 1 through
10, are labelled on
the top row of hubs. Brush
position 1 denotes the rear
brush on the brush unit.
The two upper rows of hubs, which are commoned
together vertically at each position and are labelled
ZONE PUNCHING, emit impulses for their respective
brush position when a
0, 11 or 12 punch in the card
is sensed by that brush position. The third and fourth
rows of hubs, which are commoned together at each
position and are labelled
LOWER PUNCHING, emit im-
pulses for their respective brush positions when a digit
punch in the card, 1 through
9, is sensed by that brush
position.
The lower row of selector hubs, 9 through 12, are
entry hubs for the reception of impulses emitted from
the brush hubs. These selector hubs are internally wired
to a selecting commutator which
acts as a rotary switch
to direct impulses to perform the proper function with-
in the machine, depending upon the timing of the
impulse received.
The
SC hub is an entry hub for the reception of im-
pulses emitted from the brush hubs. It is usually used
to permit selection of a common digit or digits from
one or a multiple number of columns within the span
of the ten position brush.
Common Digit Selection
It may be desired to sort out all cards which have
one or more common digit punches in
anyone of
a multiple number of columns.
Figure 44 shows the
control panel wiring necessary to accomplish this.
When the SC hub is used, the brush selection for sort-
ing switches should
be set to SELECT and all contact
bars on the sorting selector commutator should be re-
tracted towards the center, except for those necessary
to select the common digit or digits. Both the zero-
eliminate and multiple column selection control
Selection of a predet~rmined digit occurring in anyone or more of
brush positions, 1,2,4,9, or 10. Selecting commutator contact bar OUT
for digit value desired. All others IN. All brush selection for sorting
switches set to SELECT. Zero-eliminate and MCS control switches - OFF.
Figure 44. Control Panel Wiring - Common Digit Selection