Signed overpunch

A signed overpunch is a code used to store the sign of a number by changing the last digit. It is used in COBOL, especially when using EBCDIC. Its purpose is to save a character that would otherwise be used by the sign digit.^[1] The code is derived from the Hollerith Punched Card Code, where both a digit and a sign can be entered in the same card column.

The codes

Code	Digit	Sign
}	0	−
J	1	−
K	2	−
L	3	−
M	4	−
N	5	−
O	6	−
P	7	−
Q	8	−
R	9	−
{	0	+
A	1	+
B	2	+
C	3	+
D	4	+
E	5	+
F	6	+
G	7	+
H	8	+
I	9	+

Examples

10} is -100
45A is 451

Decimal points are usually implied and not explicitly stated in the text. Using numbers with two decimal digits:

1000} is -100.00

References

↑ "Tech Talk, COBOL Tutorials, EBCDIC to ASCII Conversion of Signed Fields". Retrieved 2008-03-15.

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Code	Digit	Sign
}	0	−
J	1	−
K	2	−
L	3	−
M	4	−
N	5	−
O	6	−
P	7	−
Q	8	−
R	9	−
{	0	+
A	1	+
B	2	+
C	3	+
D	4	+
E	5	+
F	6	+
G	7	+
H	8	+
I	9	+

Code	Digit	Sign
}	0	−
J	1	−
K	2	−
L	3	−
M	4	−
N	5	−
O	6	−
P	7	−
Q	8	−
R	9	−
{	0	+
A	1	+
B	2	+
C	3	+
D	4	+
E	5	+
F	6	+
G	7	+
H	8	+
I	9	+

Code	Digit	Sign
}	0	−
J	1	−
K	2	−
L	3	−
M	4	−
N	5	−
O	6	−
P	7	−
Q	8	−
R	9	−
{	0	+
A	1	+
B	2	+
C	3	+
D	4	+
E	5	+
F	6	+
G	7	+
H	8	+
I	9	+