IBM 29 User Manual

Theory of Operation
• Key the significant number.
• Make corrections before the field is punched.
• Press the left-zero key or dash key.
Using the program card shown in Figure 1-3, the ma-
chine stops in the high-order column of the left-zero
field.
The operator can key any number of significant
digits. If the operator keys more digits than the field
will hold, the first digits keyed will be lost (added, or
jumbled) . If the wrong number is keyed or more digits
Read-in
than required are entered, the operator can clear the
field by pressing the error reset key. Then the operator
can key the correct information and punch out by
pressing the left-zero or dash key.
When the operator presses the left-zero or dash keys,
the machine punches out the information stored, in-
cluding the necessary number of zeros.
• The program card coding (Figure 1-3) indicates a left-zero field.
• The operator presses the first digit key.
• A punch clutch cycle without escapement or punching is necessary.
• The keyboard is restored.
• The first digit is stored in the 8th register.
Description
The machine is stopped at an eight-column left-zero
field; the operator wishes to enter the correct digits
before pressing the left-zero key. Escapement to the
next column must be prevented until the left-zero key
is pressed. The punch clutch is energized each cycle,
but the circuit to the interposer magnets is open until
the left-zero key is pressed.
1-4
To reduce the number of relays needed in each
register to store the information as it is keyed, the
decimal digits are converted into BCD (binary coded
decimal) as shown in Figure 1-4. Example: Using the
program card in Figure 1-3, the machine is stopped
at column 10 of the program card. 1'he number to be
keyed in this example is 46078 (Figure 1-5).

IBM 29 Specifications

General

Brand	IBM
Model	29
Category	Computer Hardware
Language	English