A
Punch 12–1
Hollerith Punched-Card Code
Decode the 12-row punch patterns on an IBM-style card: A–Z and 0–9, shown as actual column diagrams.
A–I use the 12 zone, J–R use the 11 zone, S–Z use the 0 zone (with rows 2–9); digits punch their own row.
Complete reference chart
B
Punch 12–2
C
Punch 12–3
D
Punch 12–4
E
Punch 12–5
F
Punch 12–6
G
Punch 12–7
H
Punch 12–8
I
Punch 12–9
J
Punch 11–1
K
Punch 11–2
L
Punch 11–3
M
Punch 11–4
N
Punch 11–5
O
Punch 11–6
P
Punch 11–7
Q
Punch 11–8
R
Punch 11–9
S
Punch 0–2
T
Punch 0–3
U
Punch 0–4
V
Punch 0–5
W
Punch 0–6
X
Punch 0–7
Y
Punch 0–8
Z
Punch 0–9
0
Punch 0
1
Punch 1
2
Punch 2
3
Punch 3
4
Punch 4
5
Punch 5
6
Punch 6
7
Punch 7
8
Punch 8
9
Punch 9
Reading the holes
A code column has positions 12, 11, 0, 1, 2, …, 9. Dark bars represent holes. For example, A is 12+1, R is 11+9, S is 0+2, and 7 is the hole in row 7.