COM Port

[sammy1977]

I want to be able to set/reset the DTR signal on the serial port from C++. Has anyone done this before? I don't need to send any data just be able to turn on and off the DTR pin.

[greve]

That's a member of a class I once have written to wrap RS232-functionality.
m_hdl is the HANDLE you retrieve from CreateFile.

Best Regards, Thomas


void CRS232::SwitchDTRLine(bool ToBeSwitchedOn)
{
DCB CurrDCB;

GetCommState(m_hdl, &CurrDCB);
CurrDCB.fDtrControl=
ToBeSwitchedOn
?
DTR_CONTROL_ENABLE
:
DTR_CONTROL_DISABLE
;
SetCommState(m_hdl, &CurrDCB);
}