Arturia KeyStep Pro Keyboard with Advanced Sequencer and Arpeggiator - Manual (Page 176)

10.3.1. KeyStep Control Mode and VCV Rack
As we've seen previously in Chapter 8 [p.137] , MIDI CC# (control change) messages can
be used to control/modulate parameters of external synths and modular systems. These
MIDI CC# messages differ from note-related MIDI messages (for example, Note ON and
Note OFF). CC# messages are specifically designed to control/modulate parameters on an
external MIDI device such as a hardware synth, a hardware modular system, a software
virtual instrument loaded in a DAW, or a software modular system such as VCV Rack.
Sending CC# messages from the KeyStep Pro
To send CC# messages to external devices, the KeyStep Pro has to be in Control mode.
The moment you press the Control button, the five main encoders take on a different role:
they transmit CC# messages over MIDI (via USB, MIDI Out 1 and/or MIDI Out 2).
170 Arturia - User Manual Keystep Pro - KeyStep Pro and your Modular system