The CP4 Stage is a four Zone Master Keyboard Controller.

Like most keyboards the CP4 Stage normally Outputs MIDI data when you touch the keys.
MAIN - Channel 1
LAYER - Channel 2
SPLIT - Channel 3

Without any special setup, this is the normal MIDI I/O setup for the instrument.

If you are going to be using the CP4 Stage as the main Master Controller in a Stage Setup, it is highly recommended that use the MASTER KEYBOARD Function that allows you to create a four Zone setup that addresses devices connected via MIDI. These setups can be customized per Performance... so that when you recall a stage Performance the internal and external devices that you wish to play are configured as you require.

When you setup and activate the Master Keyboard 4-Zone Setup, it overrides the Normal Channel Output (which is three channels).

Thank you Bad Mister for your explanation. I think I understand what you have said. I assume then that it is imperative that in each zone I assign a specific key range so that when I play a note in that range it outputs on the MIDI channel to which the note is included. And further, all 4 zones can include the same notes. For example, if all 4 zones are activated and the assigned key range in each zone covers the entire keyboard, each note I play on the keyboard will output on 4 different MIDI channels at the same time. Is this correct? Thanks in advance.

Any time you want to intelligently Control an external device OUT via MIDI, you use the Master Keyboard feature within each CP4 Stage Performance.
You actually activate the Master Keyboard Switch, and from that moment you can determine what goes out via MIDI from the CP4 Stage Keyboard without adversely affecting what is happening with the CP4’s internal tone engine.

Thank you.

Sorry for the noob question re CP4 split zones.. how many split zones can I create on the CP4 without using Master Kbd mode?

Without the Master Keyboard function, the CP4 Stage can transmit an upper and a lower region with a single designated Split Point. The Main (M) and Layer (L) Part to the right of the Split Point. The Split (S) Part below the Split Point.

The note defining the Split Point is considered “upper“. Without the Master Keyboard Transmit Channels are fixed.

Is it possible when using the Master Keyboard function, to change the Sliders CC numbers?