不知这个对你有没有用，你看看吧
procedure TForm1.Button1Click(Sender: TObject);
var
CommPort : string;
hCommFile : THandle;
ModemStat : DWord;
begin
CommPort := 'COM2';
{Open the comm port}
hCommFile := CreateFile(PChar(CommPort),
GENERIC_READ,
0,
nil,
OPEN_EXISTING,
FILE_ATTRIBUTE_NORMAL,
0);
if hCommFile = INVALID_HANDLE_VALUE then
begin
ShowMessage('Unable to open '+ CommPort);
exit;
end;
{Get the Modem Status}
if GetCommModemStatus(hCommFile, ModemStat) <> false then begin
if ModemStat and MS_CTS_ON <> 0 then
ShowMessage('The CTS (clear-to-send) is on.');
if ModemStat and MS_DSR_ON <> 0 then
ShowMessage('The DSR (data-set-ready) is on.');
if ModemStat and MS_RING_ON <> 0then
ShowMessage('The ring indicator is on.');
if ModemStat and MS_RLSD_ON <> 0 then
ShowMessage('The RLSD (receive-line-signal-detect) is
on.');
end;
{Close the comm port}
CloseHandle(hCommFile);
end;
/////////////////////////////////////////////////
FHandle := CreateFile(PChar(DeviceName), GENERIC_READ or GENERIC_WRITE, 0,
nil, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL or FILE_FLAG_OVERLAPPED, 0);
if FHandle = INVALID_HANDLE_VALUE then
begin
Showmessage("ERROR_FILE_NOT_FOUND" );
end
else
GetCommState(FHandle,lpDCB) where lpDcb
points to the DCB(Device-control block) structure in which the control settings information is returned.
After that U can check the various properties of DCB like :
typedef struct _DCB { // dcb
DWORD DCBlength; // sizeof(DCB)
DWORD BaudRate; // current baud rate
DWORD fBinary: 1; // binary mode, no EOF check
DWORD fParity: 1; // enable parity checking
DWORD fOutxCtsFlow:1; // CTS output flow control
DWORD fOutxDsrFlow:1; // DSR output flow control
DWORD fDtrControl:2; // DTR flow control type
DWORD fDsrSensitivity:1; // DSR sensitivity
DWORD fTXContinueOnXoff:1; // XOFF continues Tx
DWORD fOutX: 1; // XON/XOFF out flow control
DWORD fInX: 1; // XON/XOFF in flow control
DWORD fErrorChar: 1; // enable error replacement
DWORD fNull: 1; // enable null stripping
DWORD fRtsControl:2; // RTS flow control
DWORD fAbortOnError:1; // abort reads/writes on error
DWORD fDummy2:17; // reserved
WORD wReserved; // not currently used
WORD XonLim; // transmit XON threshold
WORD XoffLim; // transmit XOFF threshold
BYTE ByteSize; // number of bits/byte, 4-8
BYTE Parity; // 0-4=no,odd,even,mark,space
BYTE StopBits; // 0,1,2 = 1, 1.5, 2
char XonChar; // Tx and Rx XON character
char XoffChar; // Tx and Rx XOFF character
char ErrorChar; // error replacement character
char EofChar; // end of input character
char EvtChar; // received event character
WORD wReserved1; // reserved; do not use
} DCB;
The device name Should be the name of the device like
COM1,COM2 etc
