Human Factors Criteria for the Design and Acquisition of ... - FAA

Keyboards June 20049.16.4 User selectable key repeat rate. Users should beable to set the initial delay and repeat rate for keys.[Source: NUREG 0700, 2002]Additional information. Allowing the user to select therepeat rate accommodates users with disabilities whomay require a longer delay.9.16.5 Connection point for alternative input device. Acomputer or computer system should provide a point atwhich an alternative input device can be connected ifmodifications cannot be made to make a standard inputdevice accessible. [Source: Scadden & Vanderheiden, 1988]9.16.6 Non-visual indication of state of toggle keys. Acomputer or computer system should provide blind userswith a non-visual indication of the state of toggle keysthat is available automatically or upon the user's request.[Source: Scadden & Vanderheiden, 1988]9.16.7 Key demarcation. All keys should have edgesthat can be discerned by touch. [Source: Scadden &Vanderheiden, 1988]Additional information. Flat, membrane keyboardswithout ridges outlining the keys can be particularlydifficult for the visually impaired to use. [Source: Scadden& Vanderheiden, 1988]9.16.8 Key labels. Alternatives to visual key labelingshould be made available for visually impaired users.[Source: Scadden & Vanderheiden, 1988]9.16.9 Distinguishing macro input from typed input.Computers and computing systems should be able tokeep up with assistive software input. [Source: Scadden &Vanderheiden, 1988]Additional information. Keystrokes generated byassistive devices or assistive software may be sent fasterthan the application software can recognize them, inwhich case, they may be ignored, thus preventing use ofthe assistive device or software. [Source: Scadden &Vanderheiden, 1988]9-41