Hi
From your description, you want to select values in SharePoint list automatically when you scan a label.
SharePoint doesn't support this kind of API to connect to the scanner.
For your requirement, you need to custom SharePoint API and Scanner API, then use some code to connect the SharePoint and Scanner. Or you can use third party tools to connect them.
Here are similar issue post for your reference:
https://social.technet.microsoft.com/Forums/sharepoint/en-US/8a408aa0-62bc-41a7-ad82-35a8708f7bef/sharepoint-2010-and-barcode-scanner-how-to-read-the-values-from-barcode-and-insert-to-sharepoint?forum=sharepointgeneralprevious
http://sharepoint.stackexchange.com/questions/96423/scan-documents-from-scanner-and-store-directly-into-sharepoint-library
Besides, as the issue is related to scanner, you can ask the scanner forum for help.
Hope that make senses.
Best Regards
Lisa Chen