We have had reports of losing the functonality of the F21 key on the PC due to the installation of other software on the PC. The way you can test if the PC keyboard has been re-mapped is to use the command WRKACTJOB
Then use F21=Nondisplay instructions/keys or it will say Display instructions/keys. If the screen does not change then the F21 key has been remapped.
For more information on keyboard mapping visit – http://publib.boulder.ibm.com/infocenter/pcomhelp/v5r9/index.jsp?topic=/com.ibm.pcomm.doc/books/html/emulator_reference11.htm