To convert the zoned ASCII field which results from an EBCDIC to ASCII character translation to a leading sign numeric field,
inspect the last digit in the field.
If it's a "{" replace the last digit with a 0 and make the number positive. If it's an "A" replace the last digit with a 1 and make the number positive, if it's a "B" replace the last digit with a 2 and make the number positive, etc., etc.
If the last digit is a "}" replace the last digit with a 0 and make the number negative. If it's a "J" replace the last digit with a 1 and make the number negative, if it's a "K" replace the last digit with a 2 and make the number negative, etc., etc. Follow these rules for all possible values. You could do this with a look-up table or with IF or CASE statements. Use whatever method suits you best for the language you are using. In most cases you should put the sign immediately before the first digit in the field. This is called a floating sign, and is what most PC programs expect. For example, if your field is 6 bytes, the value -123 should read " -123" not "- 123".