PSC DUET Programming Kit page 385

Switch Label
All programming sessions must begin with the
Switch label in order for the scanner to recognize
them as programming labels and end with the
Switch label for the scanner to store the changes
you have made.
When changing (programming) a feature, it is a
good practice to cover the label on the opposite
page to prevent the scanner from reading both
labels since it reads both the leading and trailing
edges of all items that are scanned.
Switch Label