Screen labeled function keys
Encyclopedia
Screen-labeled function keys are a special case of function keys 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
Automated teller machine
An automated teller machine or automatic teller machine, also known as a Cashpoint , cash machine or sometimes a hole in the wall in British English, is a computerised telecommunications device that provides the clients of a financial institution with access to financial transactions in a public...

s and gas pumps. These were first developed by Hewlett-Packard
Hewlett-Packard
Hewlett-Packard Company or HP is an American multinational information technology corporation headquartered in Palo Alto, California, USA that provides products, technologies, softwares, solutions and services to consumers, small- and medium-sized businesses and large enterprises, including...

 in the 1970s. The HP 9830
HP 9830
The HP 9800 was a family of what were initially called programmable calculators and later desktop computers made by Hewlett-Packard, replacing their first HP 9100 calculator...

 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
HP 2640
The HP 2640A and other HP 264X models were block-mode "smart" and intelligent ASCII standard serial terminals produced by Hewlett Packard using the Intel 8008 and 8080 microprocessors.-History:...

 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
Escape sequence
An escape sequence is a series of characters used to change the state of computers and their attached peripheral devices. These are also known as control sequences, reflecting their use in device control. Some control sequences are special characters that always have the same meaning...

 or configuration screen. This would be further developed on the failed HP 300
HP 300
The HP 300 "Amigo" was a computer produced by Hewlett Packard in the late 1970s based loosely on the stack-based HP 3000, but with virtual memory for both code and data...

 Amigo, which used keys at the right side of the screen and HP 250
HP 250
The HP 250 was a multiuser business computer by Hewlett Packard running HP250 BASIC language as its OS with access to HP's IMAGE database management. It was produced by the General Systems Division , but was a major repackaging of desktop workstation HP 9835 which had been sold in small business...

 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

, HP calculators use this arrangement to implement hierarchical trees of functions. 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
Texas Instruments
Texas Instruments Inc. , widely known as TI, is an American company based in Dallas, Texas, United States, which develops and commercializes semiconductor and computer technology...

 calculators such as the TI-89 series
TI-89 series
The TI-89 and the TI-89 Titanium are graphing calculators developed by Texas Instruments. They are differentiated from most other TI graphing calculators by their computer algebra system, which allows symbolic manipulation of algebraic expressions...

 use function keys to open drop-down menus on their menu bar, the menu title acting like the key label.

Casio
Casio
is a multinational electronic devices manufacturing company founded in 1946, with its headquarters in Shibuya, Tokyo, Japan. Casio is best known for its electronic products, such as calculators, audio equipment, PDAs, cameras, musical instruments, and watches...

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