OT=2 for an output file
OF=2 for a PDF format file
That implies you already defined some env variables.
For more info, just kick pssqr on the OS prompt, you'll get all the options.
Or you could try to define a icon on your desktop pointing to the PSSQRW.EXE command and define the target as following - maybe the simplest way :
-ZIF+ps_home_path+\sqr\pssqr.ini -i+ps_home_path+\sqr\ -f+output_directory+ -KEEP -PRINTER:PD