[AT]
Expects: AH    03H
AL    05H
BH    delay code
BL    typematic rate code
                                                                  
Returns: (none)
                                                                  
Info: This sets how soon the keyboard hardware will begin repeating a
key and how fast each repeat should occur.

BL delay code:  00H = 250 ms (м sec)
01H = 500 ms (л sec)
02H = 750 ms
03H = 1000 ms (1 second)
else (reserved)

BH repeat code: 00H = 30   repeats per second
01H = 26.7 repeats per second
01H = 24   repeats per second
01H = 21.8 repeats per second
... (etc.) ...
1fH = 2    repeats per second

Notes:   See AT Keyboard for related details.

  Keyboard speed setting has always been awkward to implement
cleanly since there is no corresponding fn to obtain the
current rate or delay.

See Also: INT 16H (BIOS keyboard services)
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INT 16H 03H: Set Keyboard Typematic Rate and Delay