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

Keyboards June 2004GlossaryABC keyboardAbductionAlphanumerickeysArrow keysAssistivetechnologyA keyboard layout based on the alphabet starting with theletter A in the upper left part of the keyboard.A movement of a body segment in a lateral plane awayfrom the midline of the body, such as raising the armsideways.The letters of the alphabet, numerals, and punctuationsymbols (numeric keypads may be separate on portablecomputers).A set of keys dedicated to controlling the movement of thecursor labeled with arrows indicating the direction ofmovement (also known as cursor keys).Any item, piece of equipment, or system, whether acquiredcommercially, modified, or customized, that is commonlyused to increase, maintain, or improve functionalcapabilities of individuals with disabilities.Backlit keyboard Backlit keyboards are designed for low ambient lightconditions where a standard keyboard cannot be used. Thebacklighting generally uses LED technology to illuminatethe keys on the keyboard, to allow the user to operate thekeyboard in varying ambient lighting conditions.Chord keyboardCarpal TunnelSyndrome (CTS)ContrastmodulationContrast ratioA keyboard that uses multiple simultaneous keycombinations to create characters, instead of having onecharacter per key. One advantage to a chord keyboard isthat it can take up less space than traditional keyboards. Adisadvantage is that it generally requires significanttraining time to learn the chords.A disorder of the wrist due to compression of the nerveoften associated with keyboard or input device use.An equation derived to represent the higher contrastsneeded by characters less than 20 min of arc to make themequally perceptible as a larger character.The luminance of the symbol (or text) divided by theluminance of the immediate background. It is sometimescalled luminance ratio.9-42