0:496h Keyboard Status and Type Flags
This byte holds keyboard status information.
Keyboard Status Information
x . . . . . . . Read ID in progress
. x . . . . . . Last character was first ID character
. . x . . . . . Force Num Lock if read ID and KBX
. . . x . . . . 101/102-key keyboard installed
. . . . x . . . Right Alt key is pressed
. . . . . x . . Right Ctrl key is pressed
. . . . . . x . Last code was E0 Hidden Code
. . . . . . . x last code was E1 Hidden Code
Use INT 16h, Service 12h, to obtain some of this information.
Addresses 0:417h and 0:418h also contain keyboard status information.