Blocking
Provided by the ASK Keyboard Dictionary
Aka/also known as: anti-ghosting, phantom key detection
Blocking is a means of preventing ghosting on ohmic keyboards limited to 2-key rollover. As missing keystrokes are considered preferable to reporting keys that haven't been pressed, the keyboard's firmware will detect when an attempted key combination cannot be reliably sensed and ignore all keys that could be the result of ghosting. Laptops such as ThinkPads may also provide the option to beep when "Unmanageable Key Combinations" are detected so missed keys aren't silently discarded.