Not exactly a programming question, but close. I'll try my luck anyway.
The keyboard wedge barcode scanner inserts the translation device between the reader and the keyboard. Data sent through a wedge appears as if it was typed into the computer, while the keyboard itself remains fully functional. Because a computer using a keyboard wedge can't tell the difference between data that is entered by a scanning device, or data that is entered by keyboard typing, a wedge can be used to easily add barcode reading capability to an existing computer without modifying software applications.
I'd like to know if all USB interface barcode scanners automatically translate digital signals from a barcode reader into keyboard strokes for a applications just like wedge or is USB different from wedge?
Many thanks
There are all sorts of API to access barcode scanners -- by no means do they all work by making believe they're "the keyboard"!-) For example, here you can find a reasonable summary of possibilities (the classic rs232 approach, the "wedge" one, and USB-interface ones) albeit for a single firm producing them. Depending on what programming you're willing and able to do, your best choice might be any of these approaches, or others yet.
来源：https://stackoverflow.com/questions/2892280/usb-interface-barcode-scanners