Lexmark 1200 - Manual (Page 25)

11 Menus
If you want to disable the button sequence so users cannot
easily lock or unlock the menus from the printer operator
panel, change the password variable of the PJL JOB com-
mand. Select any non-zero value for the password vari-
able to prevent the button sequence from unlocking (or
locking) the menus. Refer to the printer Technical Reference
for more information about PJL commands.