dbx AFS224 Quickstart Guide - Manual (Page 11)

19. If you would like to lock the front panel (to prevent tampering), press and hold
the channel 1 LIVE FILTER LIFT button. Hold this button until the filter LEDs
flash all the way across (from the outside inward).
To unlock the front panel press and hold the channel 1 LIVE FILTER LIFT button until
the filter LEDs flash all the way across (from the inside outwards).
A little practice and experimentation will make you an AFS expert in no time.