Models A15 And A16 - IBM 01 Maintenance Manual

IBM DECIMAL TABULATION
Models A 15 and A 16
GENERAL INFORMATION
THE ELECTRIC DECIMAL TAB.ULAR FEATURE provides
a means of tabulating accurately to any desired figure
position, electrically, by a single touch of any key in the
decimal row. Setting tab stops will require some care and
thought on decimal tabulation. For example, if it is
de~
sired that columns of 100,000,000.00 be listed as close to-
gether as possible, it will be necessary to set every 16th
tabular stop. counting 15 spaces between the· stops. Al-
though the keyboard carries decimal tab keys numbered
through 100,000,000, it may be required to write beyond
that limit. By setting the tab stop at an earlier position,
the carriage may be stopped earlier and larger numbers
may be written, still using the decimal tabular mechanism.
For example, if the tab stop is moved four spaces to the
left, so as to accommodate an additional group, the op-
erator may tabulate to any point from 100,000,000,000 to
the comma before the hundreds position. If the tab stop
is moved eight spaces to the left, the operator may tabu-
late to any point from 100,000,000,000,000 to the comma
before the hundred thousands position. Since it is unlikely
that very narrow columns would be combined with very
wide columns, this method provides a practicable means
of dealing with numbers of unlimited size. The use of the
tabular key when using this expanded system, would not
place the carriage at the decimal point, but if it was re-
quired for some purpose, another tab stop could be set to
control it.
When instructing typists it should be made clear that a
decimal tabular key must be fully depressed. Faulty strokes
of the decimal tab keys should be avoided, because im-
proper operation may also result in a lack of selection.
It is possible to get a similar response if the operator
repeatedly strikes a decimal tab key out of time with the
cam operation so that the latch on the front bell crank
is not permitted to restore to its position. If it occurs, it
will be necessary to request that the operator adjust the
timing of her key stroke operations, not because the key
is operated too fast, but because repeated operation of
any key must be synchronized with the cam operation
cycle.
The key lever locking bar has no effect on the decimal
tab keys, and it is possible to depress one or more of
the decimal tab keys when the switch is turned off.
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