Title: How to toggle RTS and DTR lines through Win32 Visual C++ function calls under Windows NT and 9x
Date: August 7, 1998
Use the following function call:
The EscapeCommFunction function directs a specified communications device to
perform an extended function.
HANDLE hFile, // handle to communications device
DWORD dwFunc // extended function to perform
Handle to the communications device. The CreateFile function returns
Specifies the code of the extended function to perform. This parameter
can be one of the following values:
CLRDTR Clears the DTR (data-terminal-ready) signal.
CLRRTS Clears the RTS (request-to-send) signal.
SETDTR Sends the DTR (data-terminal-ready) signal.
SETRTS Sends the RTS (request-to-send) signal.
SETXOFF Causes transmission to act as if an XOFF character
has been received.
SETXON Causes transmission to act as if an XON character has
SETBREAK Suspends character transmission and places the
transmission line in a break state until the ClearCommBreak function is
called (or EscapeCommFunction is called with the CLRBREAK extended function
code). The SETBREAK extended function code is identical to the SetCommBreak
function. Note that this extended function does not flush data that has not
CLRBREAK Restores character transmission and places the
transmission line in a nonbreak state. The CLRBREAK extended function code
is identical to the ClearCommBreak function.
If the function succeeds, the return value is nonzero.
If the function fails, the return value is zero. To get extended error
information, call GetLastError.
Windows CE: Windows CE supports the following additional flags for the
Sets the serial port in IR mode.
Sets port into normal serial mode.
Windows NT: Requires version 3.1 or later.
Windows: Requires Windows 95 or later.
Windows CE: Requires version 1.0 or later.
Header: Declared in winbase.h.
Import Library: Use kernel32.lib.
Communications Overview, Communication Functions, ClearCommBreak,
End of KDB-229