I saw a DX21 the other day and it had 'FM square','FM sawtooth' and I think 'FM pulse' in its patchbank. These are compatible with the DX100. So if you know your way around this site you should be able to find the factory bank to download. If you don't have one already, you need a sysex editor to load the file through your computer's MIDI out into your DX's in. More details on any of this, email me.mn