< hardware > (From the IBM 3270 terminal's Programmed Function Keys (PF keys)) One of a set of special keys on a computer or terminal keyboard which can be programmed so as to cause an application program to perform certain actions.
Function keys on a terminal may either generate short fixed sequences of characters, often beginning with the escape character ( ASCII 27), or the characters they generate may be configured by sending special character sequences to the terminal.
On a microcomputer keyboard, the function keys may generate a fixed, single byte code, outside the normal ASCII range, which is translated into some other configurable sequence by the keyboard device driver or interpreted directly by the application program .
(1995-02-07)