#flow control constants
SIO_DISABLE_FLOW_CTRL = 0x0
SIO_RTS_CTS_HS = (0x1 << 8)
SIO_DTR_DSR_HS = (0x2 << 8)
SIO_XON_XOFF_HS = (0x4 << 8)
#bits type
BITS_7 = 7
BITS_8 = 8
#stop bit type
STOP_BIT_1 = 0
STOP_BIT_15 = 1
STOP_BIT_2 = 2
#parity type
PARITY_NONE = 0
PARITY_ODD = 1
PARITY_EVEN = 2
PARITY_MARK = 3
PARITY_SPACE = 4
#break type
BREAK_OFF = 0
BREAK_ON = 1