The proper use of these tests to determine keyboard rollover is to discover the smallest number of keys that can always be recognized.
|This is 2-key rollover.||This is 6-key rollover.|
Modifier keys such as shift and control are NOT included in the rollover number.
The USB HID keyboard driver is limited to 6-key rollover per device. PS/2 has no such limitation. Some USB keyboards are comprised of more than one logical USB device, for example in order to get 12-key rollover.
Directions: Type some keys.
Test 1 was originally found at
Directions: You must click in the box below and then type some keys.
Test 2 is remotely hosted at