How to troubleshoot lag during POS checkout at retail stores

When POS systems at stores lag, cashiers often keep re-scanning, which can lead to duplicate orders or failed checkouts. On-site, first determine if it's a single machine or all machines that are slow. Single-machine issues are usually related to the barcode scanner, printer drivers, cache, or local network; if the whole store is slow, check the broadband, backend services, and payment gateways…