8251:
    Status: 7 = DSR
            6 = N/A
            5 = Framing
            4 = Overrun
            3 = Parity
            2 = TxEMP
            1 = RxRDY
            0 = TxRDY

    Ctrl:   7 = N/A
            6 = Reset       1=Reset to Mode word
            5 = RTS         1= -RTS low
            4 = Err Reset   1= Reset PE, OE, FE
            3 = SndBrk      1= TXD low
            2 = RxEnable    1=Enable RX
            1 = DTR         1= -DTR low
            0 = TxEnable    1= Enable TX (-CTS must be low)

Mits:
    Status: 7 = Output Device ready
            6 = N/A
            5 = Rx data available
            4 = Rx overrun
            3 = Framing error
            2 = Parity error
            1 = Xmit buffer empty
            0 = Input device ready
