Editing Rollover, blocking and ghosting (section)

===2KRO, 6KRO and others===

Sometimes, key rollover is described using a number. This practise is somewhat confusing because it means different things in different contexts.
The convention used by all serious keyboard brands is to use a number that represents the ''worst case'' of all possible key combinations on a keyboard.

'''2KRO''' is often used to describe a keyboard with blocking, and is meant to be read as "any combination of two keys are guaranteed to work, and some combinations of three or more keys will work, but others will not".

'''6KRO''' is often used to describe a keyboard that is NKRO inside but which is limited by the variant of the [[USB]] protocol it uses. This variant is often chosen because it has the least problems with finicky hosts. It allows six arbitrarily chosen keys plus any combination of the four pairs of modifiers ([[Shift key|Shift]], [[Control key|Control]], [[Alt key|Alt]] and [[Windows key|Windows]]/[[Command key|Command]]).

Some rollover quantities greater than 6, such as 12KRO, 18KRO or 22KRO are used to refer to heavily optimised matrices, or interface-limited NKRO keyboards that have got around the 6 key limit.

'''10KRO''' and '''14KRO''' are sometimes used by brands that don't adhere to the industry-standard convention for counting rollover. It most often means 6KRO over USB but counted as 6 keys + modifiers (4 or 8)