IBM 3270 Manual page 188

INDCU
INDCU004 You can type only in input fields
Explanation: You have tried to type on a
customization panel in a place where it is not
valid to do so, for example, a selectable field.
User Response: To type on a customization
panel, position the cursor on an input field. If
the cursor is on a selectable field, press PF2 to
select the option.
INDCU005 Only numbers are allowed in
this field
Explanation: You can enter only numbers 0
through 9 for the value of this field.
User Response: Correct the value in the field.
If you need to restore the previous value, move
the cursor off the field. The previous value and
message INDCUOOI appears.
INDCU006 Short name has already been
used
Explanation: Each session must have a unique
short name. The short name you have just typed
has already been used for another session.
User Response: Correct the value in the field.
If you need to restore the previous value, move
the cursor off the field. The previous value and
message INDCUOOI appears.
Appendix .A. Messages A-3