In addition to Bill's info this would give also a bit of information - (http://www.pianoworld.com/forum/ubbthreads.php/topics/2061284/Yamaha%20Disklavier%20Mark%20III%20Sel.html) and (http://www.pianoworld.com/forum/ubbthreads.php/ubb/showflat/Number/2458682/Searchpage/3/Main/167954/Words/mark+iv/Search/true/Yamaha_Disklavier_Mark_IV_Shut.html#Post2458682)
But loos like one has to be extra careful with trying to use that...
Thank you,
Dmitry