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"This keyboard is 100% functional and can still operate just like a stock VSS-30.
I have added the following modifications:
MIDI IN & MIDI OUT/THRU: In MIDI IN mode the VSS-30 can be controlled by external midi devices such as sequencers, other midi synthesizers, or a computer. In MIDI IN mode the midi out jack acts as a midi thru. In MIDI OUT mode the VSS-30 keys can be used to control external midi gear. (Note: the power must be off when switching between modes)
PITCH SELECT KNOB: Choose between the stock setting (0) or drop the pitch of the keyboard by one (-1) or two (-2) octaves.

TONE: This is basically a non-resonant low pass filter. High frequencies can be filtered out by turning the knob counter-clockwise."