The “default” mode for a USB keyboard allows submitting 6 keys + modifiers. Some boards define nontraditional input descriptors that allow more, but that mode is not guaranteed to work in places like the BIOS menu or naive KVM switches.
To avoid phantom keypresses when you hit three keys in a “square” on the matrix, a diode can be placed in series with each switch so current can’t go through an “indirect” route.
The “default” mode for a USB keyboard allows submitting 6 keys + modifiers. Some boards define nontraditional input descriptors that allow more, but that mode is not guaranteed to work in places like the BIOS menu or naive KVM switches.
To avoid phantom keypresses when you hit three keys in a “square” on the matrix, a diode can be placed in series with each switch so current can’t go through an “indirect” route.