Screen-labeled function keys: Difference between revisions

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*#redirect [[Soft key]]

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[[Image:ATMscreen.jpg|thumb|right|300px|ATM in [[Mercer Island, Washington]] with function keys]]

{{R from merge|Screen-labeled function keys}}

'''Screen-labeled function keys''' are a special case of [[soft key]] ([[function key]]s) where keys are placed near a screen, which provides labels for them. These are most commonly found in kiosk applications, such as [[automated teller machine]]s and [[gas pump]]s. These date to the late 1960s, and were particularly common in the 1980s and 1990s. An alternative to screen-labeled function keys is buttons (virtual keys) on a [[touchscreen]], where the label is directly pushable. The increased prevalence of touchscreens in the 2000s has led to a decrease in screen-labeled function keys. However, screen-labeled function keys are inexpensive and robust, and provide tactile feedback.

==History==

Early examples are found in aviation [[glass cockpit]]s, such as the Mark II avionics of the [[F-111D]] in the late 1960s/early 1970s (first ordered 1967, delivered 1970–73). [[Hewlett-Packard]] developed them for use in computers/calculators in the 1970s.{{Citation needed|date=September 2008}} The [[HP 9830]] desktop computer was the first calculator with two rows of 4 keys, over which a paper overlay would be placed. These were later adapted to terminals. Programmers found that the [[HP 2640]] terminals could lock the top two lines of the screen, so they displayed the key functions there. Starting with [[HP 2647]] terminal, the keys were re-arranged to correspond with 2 pairs of 4 labels at the bottom of the screen. These could be programmed by [[escape sequence]] or [[configuration screen]]. This would be further developed on the failed [[HP 300]] Amigo, which used keys at the right side of the screen and [[HP 250]] business computers which placed them at the bottom. By arranging functions in hierarchical trees, many functions can be implemented with only 8 keys.

==Graphical calculators==

{{As of|2008}}, HP calculators use this arrangement to implement hierarchical trees of functions.{{Citation needed|date=September 2008}} They are rarely found on PC applications, even though the first IBM PC BASIC labeled function key use at the bottom of the screen, and there were 12 function keys, patterned after use on IBM terminals.

Modern [[Texas Instruments]] calculators such as the [[TI-89 series]] use function keys to open drop-down menus on their menu bar, the menu title acting like the key label.

[[Casio]] calculators use the function keys for a menu at the bottom of the screen.

==See also==

* [[Soft key]]

{{DEFAULTSORT:Screen Labeled Function Keys}}

[[Category:Graphical user interface elements]]