In theory there is a compatability mode built into the BOSS 9. You can tell it to run BOSS 4 type programs. I never tried it to see how it would work. The BOSS 9 uses a decimal point in the feed rate and has many more powerful canned cycles. Also the BOSS 9 can hoild more than one program but must have a program name at the beginning and a M30 at the end. Why not get a ost or can this one be modified?