I have several questions related to Symbol USB barcode scanners (like LS2208)
Now I'm using the scanner in keyboard emulation mode, so it just sends the barcode characters as keyboard input. No way to communicate the status back to scanner. Question: can it be handled in some raw-usb mode where I would be able to receive scanned values and send back some status to the scanner so it would beep in some way indicating the result? If so, what tools (ideal would be for example libusb or something portable between linux and windows)
if not #1 maybe the way to do it is Zebra SDK - know of any example of bi-directional communication with a scanner and providing scan feedback?
The information you need is in the SDK and its documentation.
Zebra Scanner SDK for Linux Developer’s Guide (en)
Zebra Scanner SDK for Windows Developer’s Guide
These functions are not available in keyboard emulation mode.
It supports only USB OPOS (IBM Hand-held), IBM Table-top, SNAPI, SSI modes.
See CAPTER 3 SCANNER SDK API.
Beeper and LED can be controlled by SET_ACTION opcode with ExecCommand function.
CHAPTER 4 TEST UTILITIES & SOURCE CODE and CHAPTER 5 SAMPLE SOURCE CODE has a description of the SDK sample application.
See "Beep the beeper" and "Flush the LED" section of CHAPTER 4.