>I tried the following:

>strtofile(chr(27)+'%-12345X@PJL RDYMSG DISPLAY="MESSAGE HERE"',"hpDisplay.txt")
>!copy /b hpDisplay.txt \\server\printer
>

>and also tried with doing a net use lpt1 \\server\printer and then
>

>!copy /b hpDisplay.txt lpt1
>

>Neither one got the display on the printer to change.
>Anyone know what I am doing wrong?

I never was able to get copy to work for this under Windows, so I do this:

SET PRINT ON
hFile = FOPEN("BARCODE.CAP")
DO WHILE !FEOF(hFile)
  ??? FREAD(hFile,50)
ENDDO
=FCLOSE(hFile)

Or in your case:

SET PRINT ON
??? chr(27)+'%-12345X@PJL RDYMSG DISPLAY="MESSAGE HERE"'

But all that does on my laserjets is cause a page eject. I don't have a copy of the JCL commands, so can't say why.