On 2020-04-13 10:10, Peter Sjöberg wrote: > How can I prevent some generic qr scanners from sending anything else > than [A-Za-z0-9] while still allowing a normal keyboard to be connected > by some tech servicing the machine? You can't easily. One way I can think to do it would be to have some embedded device in the middle that acts as a USB host to the QR scanner, and a USB device to the real PC, and then filters what the scanner can send. You could, for example, put a recent Raspberry Pi 4 in between the scanner and the PC. Accept input from the scanner, filter it, and then use Linux's USB gadget framework to talk to the PC. https://www.hardill.me.uk/wordpress/2019/11/02/pi4-usb-c-gadget/ You might be able to do it without another device if you can detach the QR scanner from being handled by the kernel, and handle it yourself with libusb, but that might not be so easy because then you somehow have to re-inject the keyboard events into the input system. Regards, Dianne. To unsubscribe send a blank message to linux+unsubscribe [ at ] linux-ottawa [ dot ] org To get help send a blank message to linux+help [ at ] linux-ottawa [ dot ] org To visit the archives: https://lists.linux-ottawa.org