Read the following thread in its entirety, particularly the entries from
mels and
overover. I think it will shed some light on this subject for you, again, particularly the comment from
overover about
"while with OLDER PSR-S models only the method "Dummy MIDI file in Registration calls up a 'Song' in Songbook+" is possible." That statement seems to hint that there might be a workaround, of sorts, for using Songbook+ with your S970, but certainly not by a "direct" method, as with the Tyros 2-5 and the S775/S975.
http://www.psrtutorial.com/forum/index.php/topic,44823.msg369798.html#msg369798Now, aside from all of the Songbook+ rhetoric and back to your very original question "Will S970 accept program changes?". All MIDI keyboards and sound modules use the MIDI "Program Change" (PC) command to select the current sound (tone, voice, instrument, etc) to be played on any given MIDI Track/Channel/Part. Any such device that did not accept Program Changes would most certainly be very limited in its usefulness.
Good luck with your S970 and Songbook+ ! ! !
Roy