On the ATARI 1200XL there are 4 function keys named F1 to F4

||Function Key||produces
|F1| Cursor up
|F2| Cursor down
|F3| Cursor left
|F4| Cursor right
|Shift F1| Cursor Home 
|Shift F2| Cursor End
|Shift F3| Cursor to beginning of line
|Shift F4| Cursor to end of line
|CTRL F1| toggles Keyboard enable/disable
|CTRL F2| toggles DMA enable/disable
|CTRL F3| toggles Key-Click
|CTRL F4| toggles Standard/International character set
|Shift CTRL F1| ignored
|Shift CTRL F2| ignored
|Shift CTRL F3| ignored
|Shift CTRL F4| ignored

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see also: [Keyboard_topics]