Casio CZ/ VZ/ FZ - Pro Series

I extensively tested the CZ-5000. The only way to get 16-note 
polyphony was from the keyboard was using a patch with only DCO line. 
I seem to recall with keysplit, you could have 8-note polyphony in 
each half this way (or 4 in the left hand and 8 in the right hand if 
you wanted. My gut says this did not work via incoming midi.

As for outgoing MIDI, the keyboard (and sequencer) could send out midi 
note on events for as many notes as you could play. To test some 
assembly language code I developed for the Commodore-64, I took a 
broom handle and quickly jabbed as many keys at once as it would 
cover. (That's how I knew my MIDI I/O routine worked.)

I thought with some variations, the CZ-1's polyphony was the same, 
though I did not test it like I did the 5000.

--Steve