[synx508]

Pressure sensitivity on a musical keyboard is known as "aftertouch" and is generally implemented in a "monophonic" way, the effect of pressure on any key is applied to all the currently depressed keys. The CS-80 implements aftertouch on a per-key basis, rather than common to all the keys. This allows it to be more naturally expressive. There have been a few MIDI keyboards that implemented CS-80 style aftertouch, but it's extremely rare and many of the implementations have been less than brilliant (but Ensoniq deserves recognition for even trying to do it on some very reasonably priced equipment).