This has led to two interesting, albeit expected, discoveries about the Lexibook USB Calculator:
1. Even though it physically has no lock keys nor LEDs, it knows about the NumLock LED and advertises via its USB report descriptions that it has LEDs.
This is so that it can track NumLock state; and when it sends (say) a "9" digit, it fakes a NumLock keypress to turn NumLock on before sending the HID usage for the "9" key on the calculator keypad.
I can see the NumLock flashing briefly on, on the other keyboard that I have configured to share the modifier state; as well as the codes in the USB input reports.
2. Even though it has a "00" key, even though it is a USB-only device, even though USB defines a HID usage for a "00" key on a calculator, and even though that appears to have been in the spec since 1996 … it still sends two successive [0] keypresses.
It doesn't send the right HID usage for its [±] key, either.
#ComputerProgramming #HardwareRepair #BigClive #USBHID