Beim MOVEL steht genaueres (bei Feldern gleicher Länge):

If factor 2 is character and the result field is numeric, a minus zone is moved into the rightmost position of the result field if the zone from the rightmost position of factor 2 is a hexadecimal D (minus zone). However, if the zone from the rightmost position of factor 2 is not a hexadecimal D, a positive zone is moved into the rightmost position of the result field. Digit portions are converted to their corresponding numeric characters. If the digit portions are not valid digits, a data exception error occurs.
Und hier der Zeichensatz EBCDIC 273 (deutsch).