You can set up 4 internal Voices in a Performance. The Zone switch lets you add 4 completely independent external MIDI “zones” for controlling external MIDI gear. You can save the complete set-up as a “Master.” To set up an external (only) assignment go to [MASTER] - [EDIT] and then one of the 1-4 Number buttons. In [F1 Transmit], set TG to OFF. Your set up will now not control the internal TG (Tone Generator).