UPC-E1 stands for Universal Product Code Version E1. UPC-E1 contains numeric data only and is a fixed-length. It is typically used for shelf labeling in the Retail environment. The length of the input string for UPC-E1 is 6 numeric characters.
You must also enable UPC E to be able to decode UPC-E1.
Disable
Data Collection > Specified Scanner > EAN/UPC > Enable UPC-E1