INT 15 - Compaq SLT/286 - READ POWER CONSERVATION/MODEM CONFIGURATION
        AX = 4600h
Return: AH = modem configuration information
            bit 0 powerup state
                    0 off
                    1 on
                1 modem installed
                2 IRQ line assignment
                    0 IRQ 4
                    1 IRQ 3
                3 COM port assignment
                    0 = COM 2
                    1 = COM 1
                4 modem state
                    0 not assigned
                    1 assigned
                5 modem is on
        AL = power conservation status information
            bit 0  power source (0 internal, 1 external)
               1-2 low battery state
                    00 no low battery condition
                    01 low battery 1
                    10 reserved
                    11 low battery 2
               3-4 power conservation mode
                    00 automatic
                    01 on
                    10 off
                    11 reserved
        BH = default system inactivity timeout (1-21 minutes)
        BL = current system inactivity timeout (1-21 minutes)
        CH = default video display inactivity timeout (1-63 minutes)
        CL = current video display inactivity timeout (1-63 minutes)
        DH = default fixed disk drive inactivity timeout (1-21 minutes)
        DL = current fixed disk drive inactivity timeout (1-21 minutes)
SeeAlso: AX=4601h,INT 77