MSI Plessey - or Modified Plessey - is a digits-only barcode for shelf labels in shops and warehouses, and for stock control.

What it holds
Characters	Digits only.
Length	Up to 55 digits.
Check digit	One or two, in the scheme you choose with Check digit. They're in the bars only, not in the readable text.
Readable text	The value, under or over the bars.

Check digit
No check digit	None is added.
Mod 10	One check digit - the most common scheme, and the one a new MSI Plessey starts with.
Mod 10/10	Two Mod 10 check digits.
Mod 11	One Mod 11 check digit.
Mod 11/10	A Mod 11 check digit, then a Mod 10 one.

The scheme has to be the one your scanner, or the system that reads the codes, expects - ask whoever set them up.

The rest of the settings - text position, quiet zone, color - are in the Barcode section.

What goes wrong
Numeric only data expected.	The value has something other than digits.
Input data too long.	More than 55 digits.
This value has no Mod 11 check digit: choose another check digit.	About one value in eleven has no Mod 11 check digit, because it would work out to 10. Use another scheme, or another value.