The home row keys (Row “C” in Figure 11.19) should contain at least one tactile feature to assist users in positioning their fingers on the keyboard.
Additional Information: Current industry practice is to use a small raised bar, a dimple, or some other shape on the key cap. A tactile indicator on the home row keys, typically the “F” and “J” keys in the alphanumeric area and the “5” key on the numeric keypad, provides a reference landmark for users to orient their hands and fingers on the keyboard.100