Elaborate? 'Fraid not.
I just play them, I don't need to explain them.
Nowadays, I just read the specs like you and everyone else.
Most importantly, all I need to know is that the Tyros4 has that great FSX action, was made in Japan, is bought and paid for, and is sitting here on my keyboard stand, lights ablinkin'.
Just one of the many perks of being retired.
Do some of your serious investigating
and when and if you find out, put it in your little handy dandy Dikipedia folder for future reference.