Most USB barcode scanners permit special characters to be added at the beginning (prefix) or end (suffix) of the scanned barcode.  The most common use for this is sending a carriage return after scanning a code (the same as pressing the enter key), so that as soon as a product's SKU is read by the scanner, that product will be added to a sale (or stock order, stocktake etc).

Some scanners from previous point of sale systems may be preconfigured to use special characters, such as spaces, tildes ( ~ symbol) or other characters. We recommend removing any special prefix or suffix characters from barcode scanners compatible with Retail POS, but including a carriage return in the suffix, for easy adding of products to a sale.

Most standard USB scanners will come with a quick start guide (and also a more detailed product reference guide) containing series of barcodes and instructions on how to add or remove special characters and keys from the prefix or suffix of a scanner. For example:

Make/Model: Honeywell 1450g
Quick Start Guide: view online