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The special features described in this section provide addi-
tional flexibility for keypunch applications that require
special handling on the IBM 545.
AUXILIARYDUPLICATION
This feature enables duplicating information from a master
card on an auxiliary drumrather than from the card at the
read station. The auxiliary drum is similar to and locatedjust
behind the conventional program drum.
The information duplicated from the auxiliary duplicating
unit is punched in a master card, which is mounted on a drum,
exactly as a program card is mounted, and the drum installed
on the spindle of the auxiliary unit. The auxiliary duplicate
key manually controls this duplication. Pressing this key
starts auxiliary duplication, which continues to the end of the
field defined byfield definition punches in the program card.
The information in the master card must be in the samecol-
umns that are defined in the program card.
This type of duplication is advantageous when commonin-
formation is required for certain cards but not for others, for
example, when prepunched mastercardsare inserted.
When prepunched master cards are used, any information
common toall cards (such as date) is dropped when a new
mastercard is inserted. In this case, with the auxiliary dupli-
cation feature, the master information can readily be punched
in the first detail card of each group bypressing the aux dup
key and without reference to a source document.
SELF-CHECKING
The self-checking number feature provides for verifying nu-
meric information at the sametimeit is punched. To do this,
the numeric information must be precoded. The immediate
verification of precoded data eliminates the need of any fur-
ther verifying of this information. Thus, only the variable
data, such as quantities and amounts, need be verified by a
second operation, if desired.
Self-checking is controlled by a keyboard toggle switch and
by special punching in the program card. Theself-checking
numberfeature is available in two models: Modulus 10 and
Modulus 11. Modulus 10 is designed primarily to detect the
most commontype of errors, the incorrect keying of a single
digit, and a single transposition. Modulus 11 is designed to
detect single digit mispunches, single transpositions, and double
transpositions. The operation and programming of each type
is discussed later.
Operating Procedure
The use of the self-checking numberfeature requires that a
check digit be developed for each basic code numberto be
self-checked. Once the checkdigit for the basic code number
Special Features
has been determined, it is added to the basic code numberas
the units or last position. This, then, becomes the self-check
number, one digit longer than the original basic number.
(These check digits can be developed by computer calcula-
tions, by manualarithmetic, or by using the self-checking
number generator. See "Self-Checking Number Generator.')
More than oneself-checking field may be checked percard.
Adjacentself-checking fields must be separated byatleast
one card column.
Nospecial knowledge is required by code clerks who record
these numbers onthe original document, or by operators who
punch the numbersin cards.
The operator keys and punches the number, through the
check-digit position, as it appears on the source document.
Internal calculations verify the accuracy of the keying or
validity of the self-check number. When the number onthe
source documentis correct and the numberhas been keyed
correctly, the punching Operation is not interrupted.
If no errors are detected throughout the punchingofall the
self-check fields in the card, an 11-hole is automatically ;
punched in column 81.
.
When more than oneself-check field is programmed, suc-
oe
cessful keying of any onefield can produce an "'X" in col-
umn 81, even if the other fields are skipped. The appear-
ance of an 81X signifies that all self-check fields punched in
the card are correct, whether keyed or duplicated. Skipping °
or bypassing an entire self-check field is a valid operation.
If the numberis recorded on the source document incor-
rectly, or if the numberis punched incorrectly, the erroris
indicated by the self-check light on the keyboard after the
last digit of the self-check field is punched. A 12-holeis
automatically punchedin the units (check digit) column, and
the keyboard locks up. Whenever an error occurs, the auto-
matic 11-punch in column 81 is suppressed. Pressing the er-
ror reset key turns off the self-check light, unlocks the key-
board, and releases the error card. (The standardrelease key
is inoperative while the keyboardis locked.)
To duplicate the correctly punched fieldsof the error card
into a new card upto theself-check field in error, manually
press the dup key. Theself-check field is then repunched.
If it is punched as recorded on the source document, and the
keyboard locks again, it means that an incorrect numberap-
pears on the source document.
Operating Suggestions
Whenthefirst column ofa self-check field is reached, the
following operations can be performed:
1. The field can be manually keyed; the validity of the
numberis checkedbythearithmetic circuits.
2. The entire field can be skipped without validity check
by using the skip key.
Keypunch Mode
31
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