下面的代码可以控制Nokia n73手机拨打电话号码和挂断电话

procedure TForm1.btn1Click(Sender: TObject);

var

 Err: Cardinal;

 CommStat : _COMSTAT;

 s : string;

 W : Cardinal;

 overlap: _OVERLAPPED;

 DCB : TDCB;

 Buf : array[0..1023] of char;

 LEvent: TEvent;

 LEOL : Boolean;

 LIndex : Integer;

begin

 LEvent := TEvent.Create(nil, True, False, '');

 FComm := CreateFile('COM3', GENERIC_READ or GENERIC_WRITE, 0, nil,

                     OPEN_EXISTING, 0, 0);

 if FComm = INVALID_HANDLE_VALUE then

 begin

   ShowMessage('Error');

   Exit;

 end;

 SetupComm(FComm, 1024, 1024);  // 设置缓冲区

 BuildCommDCB('460800,N,8,1', DCB);

 SetCommState(FComm, DCB);   /// 设置串口参数

 PurgeComm(FComm, PURGE_TXCLEAR); /// 清空发送缓冲区

 ClearCommError(FComm, Err, @CommStat);  /// 清除错误状态

 s := 'atd3826041;'#13#10;  /// 拨打电话号码AT指令

 FillChar(overlap, SizeOf(overlap), 0);

 overlap.hEvent := LEvent.Handle;

 WriteFile(FComm, s[1], Length(s), W, @overlap);

 FlushFileBuffers(FComm);

 ReadFile(FComm, Buf, 1, W, @overlap);

 case LEvent.WaitFor(50) of

   wrSignaled:

     begin

       GetOverlappedResult(FComm, overlap, W, True);

       LEOL := False;

       LIndex := W;

       while not LEOL and (LIndex < SizeOf(Buf)) do

       begin

         ReadFile(FComm, Buf[LIndex], 1, W, @overlap);

         GetOverlappedResult(FComm, overlap, W, True);

         LEOL := (Buf[LIndex] = #$0A) or (Buf[LIndex] = #$0D);

         Inc(LIndex);

       end;

       try

         mmo1.Lines.Add(Buf);

       except

       end;

     end;

   wrTimeout, wrAbandoned, wrError:

     begin

       Sleep(100);

     end;

 end;

 Caption := SysErrorMessage(GetLastError);

end;

// 如果要读取当前缓冲区的所有数据，可以利用下面的代码：

 s := 'ati2;'#13#10;  /// 拨打电话号码AT指令

 FillChar(overlap, SizeOf(overlap), 0);

 overlap.hEvent := LEvent.Handle;

 WriteFile(FComm, s[1], Length(s), W, @overlap);

 FlushFileBuffers(FComm);

 Sleep(50);

 ClearCommError(FComm, Err, @CommStat);  /// 获取COM状态

 FillChar(Buf, SizeOf(Buf), 0);

 ReadFile(FComm, Buf, CommStat.cbInQue, W, @overlap);  /// CommStat.cbInQue 就是当前返回的数据总大小

procedure TForm1.btn2Click(Sender: TObject);

var

 s: string;

 W: Cardinal;

begin

 /// 挂断通话

 s := 'at+chup'#13#10;

 WriteFile(FComm, s[1], Length(s), W, nil);

 Caption := SysErrorMessage(GetLastError);

end;