MSI Plessey

MSI Plessey, often just called MSI, is a numeric barcode used mostly on store shelf labels. It’s simple, but it has several incompatible check digit methods, and the scanner has to know which one a label uses.

Decode one

Scan or paste a barcode and see every part of it.

Make one

Generate a valid barcode from fields.

Where you’ll see it

Retail shelf labels and price tags, especially in grocery stores, for stock counts and reordering.
Warehouse bin labels.

Anatomy

Part	What it is
Start	A short pattern that marks the start
Data	The digits `0` to `9`, each encoded as four binary bits
Check digits	One or two, depending on the method
Stop	A short pattern that marks the end

Each bit is a bar and a space: a wide bar and a narrow space for 1, a narrow bar and a wide space for 0.

Check digits

MSI Plessey has four common check digit methods:

Method	Check digits
Mod-10	One
Mod-11	One
Mod-10, then mod-10	Two
Mod-11, then mod-10	Two

None of them is marked in the barcode. A scanner set to the wrong method rejects every label, or worse, accepts them and passes the check digits through as data.

Plessey: the original barcode MSI was based on. It’s rarely seen now.
Interleaved 2 of 5: another numeric barcode, denser and more widely used outside shelf labels.

Gotchas

Extra digits at the end. The check digits were sent with the data, or the scanner is using a different method from the label.
Partial reads. MSI can’t detect a read of only part of the barcode. Fix the length.

Scanning it in your app

ScanField("Shelf label", text: $shelf)
    .barcodeTypes(.msiPlessey)
    .validate(.length(8))

See Validation.

Specification

There’s no formal standard. Scanner and printer manufacturers each document the variants they support.

Reference

Retail (GTIN)

Logistics and industrial

2D

Postal

Documents

Decode one

Make one

Where you’ll see it

Anatomy

Check digits

Gotchas

Scanning it in your app

Specification

Decode one

Make one

​Where you’ll see it

​Anatomy

​Check digits

​Variants and related types

​Gotchas

​Scanning it in your app

​Specification

Where you’ll see it

Anatomy

Check digits

Variants and related types

Gotchas

Scanning it in your app

Specification