To determine the code page a printer uses, check the documentation that comes with both the printer and with the operating system.

You can also choose several characters from the code page you think the printer uses and determine the numeric values for those characters. Start OpenEdge with -cpprint set to undefined, then run the following code fragment:

DEFINE VARIABLE ix AS INTEGER NO-UNDO.
OUTPUT TO PRINTER NO-MAP.
REPEAT ix = 1 to 255:
  DISPLAY ix CHR(ix).
END.
OUTPUT CLOSE.

Examine the output and compare it with likely code pages, or try different settings of -cpprint until the output is correct.