If you could reverse the polarity of the switches, the Korg could be used on a Roland G70/E80, if wired correctly into the FC-7 input.

Why you would want to do this beats me, though, when the FC-7 gives you more switches to play with

One area I thank God for my FC-7 is playing the arranger in piano mode... If you are using both hands to play, why ruin a good performance by taking your hands away from the keyboard to make variation changes, fills, breaks, etc.? And play a bunch of jazz tunes, with changes almost every beat, you are hard pressed to get those basic commands in off the buttons and get back to the chord on time. If your arranger has a way to take most of the basic stuff to your feet, give it a try. You might like it

The trouble with the FC10, though is that different arrangers use different codes to do exactly the same thing... It's about time that some standardization of these codes happened, that would make linking two arrangers (more sales... get it, you manufacturers? ) possible, and controlling them from one pedalboard. Yamaha use note numbers for style divisions. Roland use PC#'s, along with CC00/32 codes.

It's enough to make you weep