TetraCon is a stripped-down MIDI interface for the TETRA hardware synthesizer by Dave Smith. The TETRA uses both CC and NRPN commands to control its internal circuits.
There is no MIDI feedback from the Tetra Hardware device. This ensemble is meant to control TETRA in place of the hardware device. You can assign external MIDI controller to any of the knobs, or use your DAW’s automation to control the TETRA this way.