Intermec EasyCoder PD4 Programmer's Reference Manual page 59

Protect Counters
When the optional Keyboard Display Unit (KDU) is used,
the label form can be designed to "skip" a consecutive number
prompt, thereby protecting the data. This feature is especially
useful when the counter represents a serial number or other types
of number, that should never be repeated.
By placing one (1) minus sign as the first character of the
prompt, the prompt will appear only once after the form is
retrieved.
Example:
C0,10,L+1,"-Enter Serial Number:"↵
By placing two (2) minus signs as the first two characters of the
prompt, the prompt will never be displayed.
Example:
C0,10,L+1,"- -Enter Serial Number:"↵
The protected consecutive number is accessed and modified from
the optional Keyboard Display Unit only.
Enter the following when the KDU is displaying:
FORM - retrieve form
F2 - list forms vx.x
1 If necessary, press <Exit> key to display above.
2 Press <F1> key.
3 Press 4 9 1 6.
4 Press the <Form> key.
5 Key in Form name and press <Enter> to retrieve.
6 Enter or modify the consecutive number.
7 When complete, print label to store new number in memory.
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Chapter —Commands
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