INT 15 - Advanced Power Management Specification - CONNECT REAL-MODE INTERFACE
        AX = 5301h
        BX = 0000h (device ID of system BIOS)
Return: CF clear if successful
        CF set on error
            AH = error code (02h,09h) (see AX=5300h)
SeeAlso: AX=5302h,AX=5303h,AX=5304h

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