What is a MSI Plessey barcode?
MSI Plessey, also called Modified Plessey or simply MSI, is a numeric barcode developed by the MSI Data Corporation from the original Plessey code. It is best known for retail shelf-edge labels and inventory control in warehouses and stores.
Each digit is encoded with four bits, and each bit is a bar-and-space pair. MSI is not self-checking, so a check digit is normally added; the generator adds one by default and you can turn it off if your system reads MSI without it.
MSI Plessey is still found on shelf tags, but it is not used on retail products, which carry EAN or UPC codes. For new internal labels, Code 128 is denser and more widely supported.
What data can MSI Plessey hold?
Digits 0-9 only, any length. Spaces are removed. The check digit is on by default and can be turned off.
Recommended size
Keep a quiet zone of at least 10 times the narrowest bar on each side. MSI is fairly wide per digit, so keep numbers short enough to fit comfortably on shelf labels.
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Frequently Asked Questions
MSI can use several schemes, and modulo 10 is the most common. Make sure your scanner is set to the same check digit method, or it may reject the code or include the digit in the data.
MSI is a modified version of Plessey that encodes digits only. The original Plessey code can also hold the hex letters A-F and uses a different check method.
No. Products sold at retail need GS1 EAN-13 or UPC-A barcodes. MSI is for shelf labels and internal inventory.