Rational Developer for System z
PL/I for Windows, Version 8.0, Programming Guide

Using a number:

You can specify the CCSID number (with or without any number of leading zeroes), prefixed by any of the following (in any mixture of upper or lower case):

IBM_
IBM-
CP
CP_
CP-
CCSID_
CCSID-
Rational Developer for System z
PL/I for Windows, Version 8.0, Programming Guide